logicaffeine_language/parser/

mod.rs

//! Recursive descent parser for natural language to first-order logic.
//!
//! This module implements a hand-written recursive descent parser that transforms
//! natural language sentences into logical expressions. The parser operates in two
//! modes: **Declarative** for natural language propositions (Logicaffeine mode) and
//! **Imperative** for strict, deterministic scoping (LOGOS mode).
//!
//! # Architecture
//!
//! The parser is split into specialized submodules:
//!
//! | Module | Responsibility |
//! |--------|----------------|
//! | `clause` | Sentence-level parsing: conditionals, conjunctions, relative clauses |
//! | `noun` | Noun phrase parsing with determiners, adjectives, possessives |
//! | `verb` | Verb phrase parsing, event semantics, thematic roles |
//! | `modal` | Modal verbs (can, must, might) with Kripke semantics |
//! | `quantifier` | Quantifier scope: every, some, no, most |
//! | `question` | Wh-movement and question formation |
//! | `pragmatics` | Pragmatic inference during parsing |
//! | `common` | Shared utilities (copula lists, etc.) |
//!
//! # Key Types
//!
//! - [`Parser`]: The main parser struct holding tokens, state, and arenas
//! - [`ParserMode`]: Declarative (NL) vs Imperative (LOGOS) mode
//! - [`ParserGuard`]: RAII guard for speculative parsing with automatic rollback
//! - [`NegativeScopeMode`]: Wide vs narrow scope for lexically negative verbs
//! - [`ModalPreference`]: Default, epistemic, or deontic readings for modals
//!
//! # Example
//!
//! ```no_run
//! use logicaffeine_language::parser::{Parser, ParserMode, ClauseParsing};
//! # use logicaffeine_base::{Arena, Interner};
//! # use logicaffeine_language::{lexer::Lexer, drs::WorldState, arena_ctx::AstContext, analysis::DiscoveryPass, ParseError};
//! # fn main() -> Result<(), ParseError> {
//! # let mut interner = Interner::new();
//! # let mut lexer = Lexer::new("Every cat runs.", &mut interner);
//! # let tokens = lexer.tokenize();
//! # let type_registry = { let mut d = DiscoveryPass::new(&tokens, &mut interner); d.run() };
//! # let ea = Arena::new(); let ta = Arena::new(); let na = Arena::new();
//! # let sa = Arena::new(); let ra = Arena::new(); let pa = Arena::new();
//! # let ctx = AstContext::new(&ea, &ta, &na, &sa, &ra, &pa);
//! # let mut ws = WorldState::new();
//! # let mut parser = Parser::new(tokens, &mut ws, &mut interner, ctx, type_registry);
//!
//! // Lexer produces tokens, then parser produces LogicExpr
//! let expr = parser.parse_sentence()?;
//! # Ok(())
//! # }
//! ```

mod clause;
mod common;
mod modal;
mod noun;
mod pragmatics;
mod quantifier;
mod question;
mod verb;

#[cfg(test)]
mod tests;

pub use clause::ClauseParsing;
pub use modal::ModalParsing;
pub use noun::NounParsing;
pub use pragmatics::PragmaticsParsing;
pub use quantifier::QuantifierParsing;
pub use question::QuestionParsing;
pub use verb::{LogicVerbParsing, ImperativeVerbParsing};

use crate::analysis::TypeRegistry;
use crate::arena_ctx::AstContext;
use crate::ast::{AspectOperator, CompressionCodec, SendLayout, LogicExpr, NeoEventData, NumberKind, QuantifierKind, TemporalOperator, Term, ThematicRole, Stmt, Expr, Literal, TypeExpr, BinaryOpKind, MatchArm};
use crate::optimization::{by_keyword, pin_from_str, OptimizationConfig, PinSet};
use crate::ast::stmt::{ReadSource, Pattern};
use std::collections::HashSet;
use crate::drs::{Case, Gender, Number, ReferentSource};
use crate::drs::{Drs, BoxType, WorldState};
use crate::error::{ParseError, ParseErrorKind};
use logicaffeine_base::{Interner, Symbol, SymbolEq};
use crate::lexer::Lexer;
use crate::lexicon::{self, Aspect, Definiteness, Time, VerbClass};
use crate::token::{BlockType, FocusKind, Span, Token, TokenType};

pub(super) type ParseResult<T> = Result<T, ParseError>;

use std::ops::{Deref, DerefMut};

/// Determines how the parser interprets sentences.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
pub enum ParserMode {
    /// Logicaffeine mode: propositions, NeoEvents, ambiguity allowed.
    #[default]
    Declarative,
    /// LOGOS mode: statements, strict scoping, deterministic.
    Imperative,
}

/// Temporal modifier after copula: "is always Y", "is never Y", "is eventually Y".
#[derive(Debug, Clone, Copy)]
pub(super) enum CopulaTemporal {
    Always,
    Never,
    Eventually,
}

/// Controls scope of negation for lexically negative verbs (lacks, miss).
/// "user who lacks a key" can mean:
///   - Wide:   ¬∃y(Key(y) ∧ Have(x,y)) - "has NO keys" (natural reading)
///   - Narrow: ∃y(Key(y) ∧ ¬Have(x,y)) - "missing SOME key" (literal reading)
#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
pub enum NegativeScopeMode {
    /// Narrow scope negation (literal reading): ∃y(Key(y) ∧ ¬Have(x,y))
    /// "User is missing some key" - need all keys (default/traditional reading)
    #[default]
    Narrow,
    /// Wide scope negation (natural reading): ¬∃y(Key(y) ∧ Have(x,y))
    /// "User has no keys" - need at least one key
    Wide,
}

/// Controls interpretation of polysemous modals (may, can, could).
/// Used by compile_forest to generate multiple semantic readings.
///
/// Semantic Matrix:
///   may:   Default=Permission (Deontic, Root)    Epistemic=Possibility (Alethic, Epistemic)
///   can:   Default=Ability (Alethic, Root)       Deontic=Permission (Deontic, Root)
///   could: Default=PastAbility (Alethic, Root)   Epistemic=Possibility (Alethic, Epistemic)
#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
pub enum ModalPreference {
    /// Default readings: may=Permission, can=Ability, could=PastAbility
    #[default]
    Default,
    /// Epistemic readings: may=Possibility (wide scope), could=Possibility (wide scope)
    Epistemic,
    /// Deontic readings: can=Permission (narrow scope, deontic domain)
    Deontic,
}

/// Result of pronoun resolution during parsing.
///
/// Determines whether a pronoun refers to a bound variable (anaphoric) or
/// a deictic constant (referring to an entity outside the discourse).
#[derive(Debug, Clone, Copy)]
pub enum ResolvedPronoun {
    /// Bound variable from DRS or telescope (use [`Term::Variable`]).
    Variable(Symbol),
    /// Constant (deictic or proper name) (use [`Term::Constant`]).
    Constant(Symbol),
}

#[derive(Clone)]
struct ParserCheckpoint {
    pos: usize,
    var_counter: usize,
    bindings_len: usize,
    island: u32,
    time: Option<Time>,
    negative_depth: u32,
}

/// RAII guard for speculative parsing with automatic rollback.
///
/// Created by [`Parser::guard()`], this guard saves the parser state
/// on creation and automatically restores it if the guard is dropped
/// without being committed.
///
/// # Usage
///
/// ```no_run
/// # use logicaffeine_base::{Arena, Interner};
/// # use logicaffeine_language::{lexer::Lexer, drs::WorldState, arena_ctx::AstContext, analysis::DiscoveryPass, ParseError};
/// # use logicaffeine_language::parser::Parser;
/// # fn try_parse<T>(_: &mut T) -> Result<(), ParseError> { todo!() }
/// # fn main() -> Result<(), ParseError> {
/// # let mut interner = Interner::new();
/// # let mut lexer = Lexer::new("test.", &mut interner);
/// # let tokens = lexer.tokenize();
/// # let tr = { let mut d = DiscoveryPass::new(&tokens, &mut interner); d.run() };
/// # let ea = Arena::new(); let ta = Arena::new(); let na = Arena::new();
/// # let sa = Arena::new(); let ra = Arena::new(); let pa = Arena::new();
/// # let ctx = AstContext::new(&ea, &ta, &na, &sa, &ra, &pa);
/// # let mut ws = WorldState::new();
/// # let mut parser = Parser::new(tokens, &mut ws, &mut interner, ctx, tr);
/// let mut guard = parser.guard();
/// if let Ok(result) = try_parse(&mut *guard) {
///     guard.commit(); // Success - keep changes
///     return Ok(result);
/// }
/// // guard dropped here - parser state restored
/// # Ok(())
/// # }
/// ```
pub struct ParserGuard<'p, 'a, 'ctx, 'int> {
    parser: &'p mut Parser<'a, 'ctx, 'int>,
    checkpoint: ParserCheckpoint,
    committed: bool,
}

impl<'p, 'a, 'ctx, 'int> ParserGuard<'p, 'a, 'ctx, 'int> {
    /// Commits the parse, preventing rollback when the guard is dropped.
    pub fn commit(mut self) {
        self.committed = true;
    }
}

impl<'p, 'a, 'ctx, 'int> Drop for ParserGuard<'p, 'a, 'ctx, 'int> {
    fn drop(&mut self) {
        if !self.committed {
            self.parser.restore(self.checkpoint.clone());
        }
    }
}

impl<'p, 'a, 'ctx, 'int> Deref for ParserGuard<'p, 'a, 'ctx, 'int> {
    type Target = Parser<'a, 'ctx, 'int>;
    fn deref(&self) -> &Self::Target {
        self.parser
    }
}

impl<'p, 'a, 'ctx, 'int> DerefMut for ParserGuard<'p, 'a, 'ctx, 'int> {
    fn deref_mut(&mut self) -> &mut Self::Target {
        self.parser
    }
}

/// Template for constructing Neo-Davidsonian events.
///
/// Used during parsing to accumulate thematic roles and modifiers
/// before the agent is known (e.g., in VP ellipsis resolution).
#[derive(Clone, Debug)]
pub struct EventTemplate<'a> {
    /// The verb predicate.
    pub verb: Symbol,
    /// The agent term, for gapping patterns where the agent is shared/gapped
    /// ("John gave Mary a book and Sue a pen" — John is the agent of both).
    pub agent: Option<Term<'a>>,
    /// Thematic roles excluding the agent (filled later).
    pub non_agent_roles: Vec<(ThematicRole, Term<'a>)>,
    /// Adverbial modifiers.
    pub modifiers: Vec<Symbol>,
}

/// Recursive descent parser for natural language to first-order logic.
///
/// The parser transforms a token stream (from [`Lexer`]) into logical expressions
/// ([`LogicExpr`]). It handles complex linguistic phenomena including:
///
/// - Quantifier scope ambiguity
/// - Pronoun resolution via DRS
/// - Modal verb interpretation
/// - Temporal and aspectual marking
/// - VP ellipsis resolution
///
/// # Lifetimes
///
/// - `'a`: Arena lifetime for allocated AST nodes
/// - `'ctx`: WorldState lifetime for discourse tracking
/// - `'int`: Interner lifetime for symbol management
pub struct Parser<'a, 'ctx, 'int> {
    /// Token stream from lexer.
    pub(super) tokens: Vec<Token>,
    /// Current position in token stream.
    pub(super) current: usize,
    /// File-level optimization decorators: a `## No <X>` that is NOT attached to a
    /// following `## To` function (it appears before `## Main` or at EOF) applies
    /// program-wide. Read after `parse_program` via [`Parser::program_opt_flags`].
    pub(super) program_opt_flags: OptimizationConfig,
    /// File-level tiered-optimizer pins from `## Tier <opt> <value>` decorators
    /// (HOTSWAP §8): each pins one optimization to a hotness tier (or `eager`/`never`).
    /// Program-wide; read after `parse_program` via [`Parser::program_tier_pins`].
    pub(super) program_tier_pins: PinSet,
    /// Counter for generating fresh variables.
    pub(super) var_counter: usize,
    /// Every name the program BINDS (`Let`, function params) — an
    /// over-approximation that lets word literals (`infinity`, `nan`) yield
    /// to user variables of the same name (ambiguity-preserving: a bound
    /// name is never shadowed by a literal reading).
    pub(super) user_bound: std::collections::HashSet<Symbol>,
    /// Pending tense from temporal adverbs.
    pub(super) pending_time: Option<Time>,
    /// Donkey bindings: (noun, var, is_donkey_used, wide_scope_negation).
    pub(super) donkey_bindings: Vec<(Symbol, Symbol, bool, bool)>,
    /// String interner for symbol management.
    pub(super) interner: &'int mut Interner,
    /// Arena context for AST allocation.
    pub(super) ctx: AstContext<'a>,
    /// Current scope island ID.
    pub(super) current_island: u32,
    /// Whether PP attaches to noun (vs verb).
    pub(super) pp_attach_to_noun: bool,
    /// Filler for wh-movement gap.
    pub(super) filler_gap: Option<Symbol>,
    /// Depth of negation scope.
    pub(super) negative_depth: u32,
    /// Event variable for discourse coherence.
    pub(super) discourse_event_var: Option<Symbol>,
    /// Last event template for VP ellipsis.
    pub(super) last_event_template: Option<EventTemplate<'a>>,
    /// Pragmatic-enrichment mode: when set, gradable predication emits the degree-
    /// standard form (§7.2) and vagueness penumbra (§8.5), and "either…or" emits its
    /// exclusivity. Off by default so `compile()` stays literal/truth-conditional and
    /// the proof engine sees simple predicates.
    pub(super) pragmatic: bool,
    /// Whether to prefer noun readings.
    pub(super) noun_priority_mode: bool,
    /// Whether plural NPs get collective readings.
    pub(super) collective_mode: bool,
    /// A floated quantifier ("the boys ALL/EACH left") forces the
    /// distributive reading of a mixed verb that would otherwise default
    /// to the collective one.
    pub(super) distributive_marker: bool,
    /// Pending cardinal for delayed quantification.
    pub(super) pending_cardinal: Option<u32>,
    /// Parser mode: Declarative or Imperative.
    pub(super) mode: ParserMode,
    /// Type registry for LOGOS mode.
    pub(super) type_registry: Option<TypeRegistry>,
    /// Whether to produce event readings.
    pub(super) event_reading_mode: bool,
    /// Internal DRS for sentence-level scope tracking.
    pub(super) drs: Drs,
    /// Negation scope mode for lexically negative verbs.
    pub(super) negative_scope_mode: NegativeScopeMode,
    /// Modal interpretation preference.
    pub(super) modal_preference: ModalPreference,
    /// WorldState for discourse-level parsing.
    pub(super) world_state: &'ctx mut WorldState,
    /// Whether inside "No X" quantifier scope.
    pub(super) in_negative_quantifier: bool,
    /// Pending partitive superset captured from an "of the [Num]" frame:
    /// (superset_cardinality, restriction_predicate, restriction_variable). The asserted
    /// count quantifier is wrapped in a `Presupposition` whose presupposition is the
    /// superset's `Cardinal` quantifier over the same restriction (§5.3).
    pub(super) pending_partitive: Option<(u32, &'a LogicExpr<'a>, Symbol)>,
    /// A subject's relative-clause restriction that cannot be carried on the
    /// `NounPhrase` (it is a full clause, not an adjective/PP/possessor) and so
    /// is stashed — keyed to the subject noun and expressed over
    /// `Constant(noun)` — to be folded in at the `wrap_with_definiteness`
    /// chokepoint when the predicate (e.g. a copula complement) is built over
    /// the same constant. Without this, "The scent that sold for $75 is the
    /// white fragrance." silently drops the relative clause.
    pub(super) pending_subject_restriction: Option<(Symbol, &'a LogicExpr<'a>)>,
    /// Set while parsing an object NP that a determiner/cardinal/counting
    /// quantifier has ALREADY established as nominal (e.g. the cardinal was
    /// consumed by the object-quantifier gate before `parse_noun_phrase` runs).
    /// A bare verb-word after an adjective is then a DEVERBAL NOUN head ("49
    /// previous JUMPS", "six previous RUNS") — a cardinal/determiner cannot be
    /// followed by a finite verb — so `parse_noun_phrase` recovers it as the
    /// head instead of stranding it. Outside this context the determiner gate
    /// (`definiteness.is_some()`) is the only signal, to avoid eating a real
    /// main verb ("studies hard pass").
    pub(super) nominal_np_context: bool,
    /// Named acceptance contracts declared by `Accept computed <Name> where <param> is an
    /// Int from <lo> to <hi>` → `(lo, hi)`. Pure parse-time sugar: a `Run <f> on <arg> under
    /// <Name> into <var>` statement desugars to `Let <var> be run_accepted(<f>, <arg>, lo, hi)`,
    /// inlining the named contract's bounds — no new AST node, no runtime contract registry.
    pub(super) contracts: std::collections::HashMap<String, (i64, i64)>,
    /// One source span per top-level statement `parse_program` returned, in
    /// push order — the side-table that gives typechecker diagnostics,
    /// ownership cause-links, and the rustc sourcemap real spans without a
    /// span field on every `Stmt` variant. Read via [`Parser::stmt_spans`].
    pub(super) stmt_spans: Vec<Span>,
    /// Live recursion depth of the imperative descent (parenthesized
    /// expressions, nested blocks). Checked against
    /// [`crate::ast_depth::max_ast_depth`] so a parenthesis tower or block
    /// pyramid errors gracefully instead of overflowing the parser's own
    /// stack — the parse-time half of the AST depth gate.
    pub(super) recursion_depth: usize,
}

impl<'a, 'ctx, 'int> Parser<'a, 'ctx, 'int> {
    /// Create a parser with WorldState for discourse-level parsing.
    /// WorldState is REQUIRED - there is no "single sentence mode".
    /// A single sentence is just a discourse of length 1.
    pub fn new(
        mut tokens: Vec<Token>,
        world_state: &'ctx mut WorldState,
        interner: &'int mut Interner,
        ctx: AstContext<'a>,
        types: TypeRegistry,
    ) -> Self {
        // The parser's walk is total only over an EOF-terminated stream;
        // fragments and block slices can arrive without one, and a missing
        // terminator used to surface as an index-out-of-bounds panic deep
        // in `peek()`.
        if !matches!(tokens.last().map(|t| &t.kind), Some(TokenType::EOF)) {
            let end = tokens.last().map(|t| t.span.end).unwrap_or(0);
            let empty = interner.intern("");
            tokens.push(Token::new(TokenType::EOF, empty, Span::new(end, end)));
        }
        Parser {
            tokens,
            current: 0,
            contracts: std::collections::HashMap::new(),
            program_opt_flags: OptimizationConfig::all_on(),
            program_tier_pins: PinSet::none(),
            var_counter: 0,
            user_bound: std::collections::HashSet::new(),
            pending_time: None,
            donkey_bindings: Vec::new(),
            interner,
            ctx,
            current_island: 0,
            pp_attach_to_noun: false,
            filler_gap: None,
            negative_depth: 0,
            discourse_event_var: None,
            last_event_template: None,
            pragmatic: false,
            noun_priority_mode: false,
            collective_mode: false,
            distributive_marker: false,
            pending_cardinal: None,
            mode: ParserMode::Declarative,
            type_registry: Some(types),
            event_reading_mode: false,
            drs: Drs::new(), // Internal DRS for sentence-level scope tracking
            negative_scope_mode: NegativeScopeMode::default(),
            modal_preference: ModalPreference::default(),
            pending_subject_restriction: None,
            nominal_np_context: false,
            world_state,
            in_negative_quantifier: false,
            pending_partitive: None,
            stmt_spans: Vec::new(),
            recursion_depth: 0,
        }
    }

    /// The span of each top-level statement from the last `parse_program`
    /// call, aligned 1:1 with the returned statement list.
    pub fn stmt_spans(&self) -> &[Span] {
        &self.stmt_spans
    }

    /// Record the span for the statement just pushed: from the first token of
    /// `start_tok` through the last consumed token (terminating period or
    /// dedent included). `parse_program` asserts 1:1 alignment on return.
    fn record_stmt_span(&mut self, start_tok: usize) {
        let start = self
            .tokens
            .get(start_tok)
            .map(|t| t.span.start)
            .unwrap_or(0);
        let end = self
            .tokens
            .get(self.current.saturating_sub(1))
            .map(|t| t.span.end)
            .unwrap_or(start);
        self.stmt_spans.push(Span::new(start, end));
    }

    pub fn set_discourse_event_var(&mut self, var: Symbol) {
        self.discourse_event_var = Some(var);
    }

    /// Get mutable reference to the active DRS (from WorldState).
    pub fn drs_mut(&mut self) -> &mut Drs {
        &mut self.world_state.drs
    }

    /// Get immutable reference to the active DRS (from WorldState).
    pub fn drs_ref(&self) -> &Drs {
        &self.world_state.drs
    }

    /// Swap DRS between Parser and WorldState.
    /// Call at start of parsing to get the accumulated DRS from WorldState.
    /// Call at end of parsing to save the updated DRS back to WorldState.
    pub fn swap_drs_with_world_state(&mut self) {
        std::mem::swap(&mut self.drs, &mut self.world_state.drs);
    }

    /// WorldState is always present (no "single sentence mode")
    pub fn has_world_state(&self) -> bool {
        true
    }

    pub fn mode(&self) -> ParserMode {
        self.mode
    }

    /// Check if a symbol is a known type in the registry.
    /// Used to disambiguate "Stack of Integers" (generic type) vs "Owner of House" (possessive).
    pub fn is_known_type(&self, sym: Symbol) -> bool {
        self.type_registry
            .as_ref()
            .map(|r| r.is_type(sym))
            .unwrap_or(false)
    }

    /// Check if a symbol is a known generic type (takes type parameters).
    /// Used to parse "Stack of Integers" as generic instantiation.
    pub fn is_generic_type(&self, sym: Symbol) -> bool {
        self.type_registry
            .as_ref()
            .map(|r| r.is_generic(sym))
            .unwrap_or(false)
    }

    /// Get the parameter count for a generic type.
    fn get_generic_param_count(&self, sym: Symbol) -> Option<usize> {
        use crate::analysis::TypeDef;
        self.type_registry.as_ref().and_then(|r| {
            match r.get(sym) {
                Some(TypeDef::Generic { param_count }) => Some(*param_count),
                _ => None,
            }
        })
    }

    /// Phase 33: Check if a symbol is a known enum variant and return the enum name.
    fn find_variant(&self, sym: Symbol) -> Option<Symbol> {
        self.type_registry
            .as_ref()
            .and_then(|r| r.find_variant(sym).map(|(enum_name, _)| enum_name))
    }

    /// Consume a type name token (doesn't check entity registration).
    fn consume_type_name(&mut self) -> ParseResult<Symbol> {
        let t = self.advance().clone();
        match t.kind {
            TokenType::Noun(s) | TokenType::Adjective(s) => Ok(s),
            TokenType::ProperName(s) => Ok(s),
            // Verbs can be type names when lexed ambiguously (e.g., "Set" as type vs verb)
            TokenType::Verb { .. } => Ok(t.lexeme),
            // Phase 49b: CRDT type keywords are valid type names
            TokenType::Tally => Ok(self.interner.intern("Tally")),
            TokenType::SharedSet => Ok(self.interner.intern("SharedSet")),
            TokenType::SharedSequence => Ok(self.interner.intern("SharedSequence")),
            TokenType::CollaborativeSequence => Ok(self.interner.intern("CollaborativeSequence")),
            TokenType::SharedMap => Ok(self.interner.intern("SharedMap")),
            TokenType::Divergent => Ok(self.interner.intern("Divergent")),
            // Type parameter names (e.g. T, U) can be tokenized as articles by the English lexer
            TokenType::Article(_) => Ok(t.lexeme),
            other => Err(ParseError {
                kind: ParseErrorKind::ExpectedContentWord { found: other },
                span: self.current_span(),
            }),
        }
    }

    /// Parse a type expression: Int, Text, List of Int, Result of Int and Text.
    /// Phase 36: Also supports "Type from Module" for qualified imports.
    /// Uses TypeRegistry to distinguish primitives from generics.
    /// Also handles `fn(A, B) -> C` function types.
    fn parse_type_expression(&mut self) -> ParseResult<TypeExpr<'a>> {
        use noun::NounParsing;

        // Handle `fn(A, B) -> C` function type syntax
        if self.check_word("fn") {
            if let Some(next) = self.tokens.get(self.current + 1) {
                if matches!(next.kind, TokenType::LParen) {
                    self.advance(); // consume "fn"
                    self.advance(); // consume "("

                    // Parse input types
                    let mut inputs = Vec::new();
                    if !self.check(&TokenType::RParen) {
                        inputs.push(self.parse_type_expression()?);
                        while self.check(&TokenType::Comma) {
                            self.advance(); // consume ","
                            inputs.push(self.parse_type_expression()?);
                        }
                    }

                    if !self.check(&TokenType::RParen) {
                        return Err(ParseError {
                            kind: ParseErrorKind::ExpectedKeyword { keyword: ")".to_string() },
                            span: self.current_span(),
                        });
                    }
                    self.advance(); // consume ")"

                    // Expect ->
                    if !self.check(&TokenType::Arrow) {
                        return Err(ParseError {
                            kind: ParseErrorKind::ExpectedKeyword { keyword: "->".to_string() },
                            span: self.current_span(),
                        });
                    }
                    self.advance(); // consume "->"

                    let output = self.parse_type_expression()?;
                    let output_ref = self.ctx.alloc_type_expr(output);
                    let inputs_ref = self.ctx.alloc_type_exprs(inputs);
                    return Ok(TypeExpr::Function { inputs: inputs_ref, output: output_ref });
                }
            }
        }

        // Bug fix: Handle parenthesized type expressions: "Seq of (Seq of Int)"
        if self.check(&TokenType::LParen) {
            self.advance(); // consume "("
            let inner = self.parse_type_expression()?;
            if !self.check(&TokenType::RParen) {
                return Err(ParseError {
                    kind: ParseErrorKind::ExpectedKeyword { keyword: ")".to_string() },
                    span: self.current_span(),
                });
            }
            self.advance(); // consume ")"
            return Ok(inner);
        }

        // Phase 53: Handle "Persistent T" type modifier
        if self.check(&TokenType::Persistent) {
            self.advance(); // consume "Persistent"
            let inner = self.parse_type_expression()?;
            let inner_ref = self.ctx.alloc_type_expr(inner);
            return Ok(TypeExpr::Persistent { inner: inner_ref });
        }

        // Get the base type name (must be a noun or proper name - type names bypass entity check)
        let mut base = self.consume_type_name()?;

        // Phase 49c: Check for bias modifier on SharedSet: "SharedSet (RemoveWins) of T"
        let base_name = self.interner.resolve(base);
        if base_name == "SharedSet" || base_name == "ORSet" {
            if self.check(&TokenType::LParen) {
                self.advance(); // consume "("
                if self.check(&TokenType::RemoveWins) {
                    self.advance(); // consume "RemoveWins"
                    base = self.interner.intern("SharedSet_RemoveWins");
                } else if self.check(&TokenType::AddWins) {
                    self.advance(); // consume "AddWins"
                    // AddWins is default, but we can be explicit
                    base = self.interner.intern("SharedSet_AddWins");
                }
                if !self.check(&TokenType::RParen) {
                    return Err(ParseError {
                        kind: ParseErrorKind::ExpectedKeyword { keyword: ")".to_string() },
                        span: self.current_span(),
                    });
                }
                self.advance(); // consume ")"
            }
        }

        // Phase 49c: Check for algorithm modifier on SharedSequence: "SharedSequence (YATA) of T"
        let base_name = self.interner.resolve(base);
        if base_name == "SharedSequence" || base_name == "RGA" {
            if self.check(&TokenType::LParen) {
                self.advance(); // consume "("
                if self.check(&TokenType::YATA) {
                    self.advance(); // consume "YATA"
                    base = self.interner.intern("SharedSequence_YATA");
                }
                if !self.check(&TokenType::RParen) {
                    return Err(ParseError {
                        kind: ParseErrorKind::ExpectedKeyword { keyword: ")".to_string() },
                        span: self.current_span(),
                    });
                }
                self.advance(); // consume ")"
            }
        }

        // Phase 36: Check for "from Module" qualification
        let base_type = if self.check(&TokenType::From) {
            self.advance(); // consume "from"
            let module_name = self.consume_type_name()?;
            let module_str = self.interner.resolve(module_name);
            let base_str = self.interner.resolve(base);
            let qualified = format!("{}::{}", module_str, base_str);
            let qualified_sym = self.interner.intern(&qualified);
            TypeExpr::Named(qualified_sym)
        } else {
            // Phase 38: Get param count from registry OR from built-in std types
            let base_name = self.interner.resolve(base);
            // `Quantity of <Dimension>` reads its parameter leniently (a dimension word may collide
            // with a keyword token); capture the predicate as a Copy bool so the `base_name` borrow
            // does not span the `self.advance()` calls in the parameter loop below.
            let base_is_quantity = base_name == "Quantity";
            let param_count = self.get_generic_param_count(base)
                .or_else(|| match base_name {
                    // Built-in generic types for Phase 38 std library
                    "Result" => Some(2),    // Result of T and E
                    "Option" | "Maybe" => Some(1),    // Option of T / Maybe T
                    "Seq" | "List" | "Vec" => Some(1),  // Seq of T
                    "Set" | "HashSet" => Some(1), // Set of T
                    "Map" | "HashMap" => Some(2), // Map of K and V
                    "Pair" => Some(2),      // Pair of A and B
                    "Triple" => Some(3),    // Triple of A and B and C
                    // Phase 49b: CRDT generic types
                    "SharedSet" | "ORSet" | "SharedSet_AddWins" | "SharedSet_RemoveWins" => Some(1),
                    "SharedSequence" | "RGA" | "SharedSequence_YATA" | "CollaborativeSequence" => Some(1),
                    "SharedMap" | "ORMap" => Some(2),      // SharedMap from K to V
                    "Divergent" | "MVRegister" => Some(1), // Divergent T
                    _ => None,
                });

            // Check if it's a known generic type with parameters
            if let Some(count) = param_count {
                let has_preposition = self.check_of_preposition() || self.check_preposition_is("from");
                // Maybe supports direct syntax without "of": "Maybe Int", "Maybe Text"
                let maybe_direct = !has_preposition && base_name == "Maybe" && matches!(
                    self.peek().kind,
                    TokenType::Noun(_) | TokenType::Adjective(_) | TokenType::ProperName(_) | TokenType::Verb { .. }
                );
                if has_preposition || maybe_direct {
                    if has_preposition {
                        self.advance(); // consume "of" or "from"
                    }

                    let mut params = Vec::new();
                    for i in 0..count {
                        if i > 0 {
                            // Expect separator for params > 1: "and", "to", or ","
                            if self.check(&TokenType::And) || self.check_to_preposition() || self.check(&TokenType::Comma) {
                                self.advance();
                            }
                        }
                        // `Quantity of <Dimension>` takes a DIMENSION NAME, which can collide with a
                        // keyword token (`Length` is the `length of` keyword). Read it leniently by
                        // lexeme so any dimension word is accepted in this position.
                        let param = if base_is_quantity {
                            let dim_sym = self.peek().lexeme;
                            self.advance();
                            TypeExpr::Named(dim_sym)
                        } else {
                            self.parse_type_expression()?
                        };
                        params.push(param);
                    }

                    let params_slice = self.ctx.alloc_type_exprs(params);
                    TypeExpr::Generic { base, params: params_slice }
                } else {
                    // Generic type without parameters - treat as primitive or named
                    let is_primitive = self.type_registry.as_ref().map(|r| r.is_type(base)).unwrap_or(false)
                        || matches!(
                        base_name,
                        "Int" | "Nat" | "Text" | "Bool" | "Boolean" | "Real" | "Unit"
                            | "Word8" | "Word16" | "Word32" | "Word64" | "Lanes8Word32"
                            | "Lanes4Word32" | "Lanes16Word8" | "Lanes4Word64" | "Lanes16Word16"
                    );
                    if is_primitive {
                        TypeExpr::Primitive(base)
                    } else {
                        TypeExpr::Named(base)
                    }
                }
            } else {
                // Check if it's a known primitive type (Int, Nat, Text, Bool, Real, Unit)
                let is_primitive = self.type_registry.as_ref().map(|r| r.is_type(base)).unwrap_or(false)
                    || matches!(
                        base_name,
                        "Int" | "Nat" | "Text" | "Bool" | "Boolean" | "Real" | "Unit"
                            | "Word8" | "Word16" | "Word32" | "Word64" | "Lanes8Word32"
                            | "Lanes4Word32" | "Lanes16Word8" | "Lanes4Word64" | "Lanes16Word16"
                    );
                if is_primitive {
                    TypeExpr::Primitive(base)
                } else {
                    // User-defined or unknown type
                    TypeExpr::Named(base)
                }
            }
        };

        // Phase 43C: Check for refinement "where" clause
        if self.check(&TokenType::Where) {
            self.advance(); // consume "where"

            // Parse the predicate expression (supports compound: `x > 0 and x < 100`)
            let predicate_expr = self.parse_condition()?;

            // Extract bound variable from the left side of the expression
            let bound_var = self.extract_bound_var(&predicate_expr)
                .unwrap_or_else(|| self.interner.intern("it"));

            // Convert imperative Expr to logic LogicExpr
            let predicate = self.expr_to_logic_predicate(&predicate_expr, bound_var)
                .ok_or_else(|| ParseError {
                    kind: ParseErrorKind::InvalidRefinementPredicate,
                    span: self.peek().span,
                })?;

            // Allocate the base type
            let base_alloc = self.ctx.alloc_type_expr(base_type);

            return Ok(TypeExpr::Refinement { base: base_alloc, var: bound_var, predicate });
        }

        Ok(base_type)
    }

    /// Extracts the leftmost identifier from an expression as the bound variable.
    fn extract_bound_var(&self, expr: &Expr<'a>) -> Option<Symbol> {
        match expr {
            Expr::Identifier(sym) => Some(*sym),
            Expr::BinaryOp { left, .. } => self.extract_bound_var(left),
            _ => None,
        }
    }

    /// Converts an imperative comparison Expr to a Logic Kernel LogicExpr.
    /// Used for refinement type predicates: `Int where x > 0`
    fn expr_to_logic_predicate(&mut self, expr: &Expr<'a>, bound_var: Symbol) -> Option<&'a LogicExpr<'a>> {
        match expr {
            Expr::BinaryOp { op, left, right } => {
                // Map BinaryOpKind to predicate name
                let pred_name = match op {
                    BinaryOpKind::Gt => "Greater",
                    BinaryOpKind::Lt => "Less",
                    BinaryOpKind::GtEq => "GreaterEqual",
                    BinaryOpKind::LtEq => "LessEqual",
                    BinaryOpKind::Eq => "Equal",
                    BinaryOpKind::NotEq => "NotEqual",
                    BinaryOpKind::And => {
                        // Handle compound `x > 0 and x < 100`
                        let left_logic = self.expr_to_logic_predicate(left, bound_var)?;
                        let right_logic = self.expr_to_logic_predicate(right, bound_var)?;
                        return Some(self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                            left: left_logic,
                            op: TokenType::And,
                            right: right_logic,
                        }));
                    }
                    BinaryOpKind::Or => {
                        let left_logic = self.expr_to_logic_predicate(left, bound_var)?;
                        let right_logic = self.expr_to_logic_predicate(right, bound_var)?;
                        return Some(self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                            left: left_logic,
                            op: TokenType::Or,
                            right: right_logic,
                        }));
                    }
                    _ => return None, // Arithmetic ops not valid as predicates
                };
                let pred_sym = self.interner.intern(pred_name);

                // Convert operands to Terms
                let left_term = self.expr_to_term(left)?;
                let right_term = self.expr_to_term(right)?;

                let args = self.ctx.terms.alloc_slice([left_term, right_term]);
                Some(self.ctx.exprs.alloc(LogicExpr::Predicate { name: pred_sym, args, world: None }))
            }
            _ => None,
        }
    }

    /// Converts an imperative Expr to a logic Term.
    fn expr_to_term(&mut self, expr: &Expr<'a>) -> Option<Term<'a>> {
        match expr {
            Expr::Identifier(sym) => Some(Term::Variable(*sym)),
            Expr::Literal(lit) => {
                match lit {
                    Literal::Number(n) => Some(Term::Value {
                        kind: NumberKind::Integer(*n),
                        unit: None,
                        dimension: None,
                    }),
                    Literal::Boolean(b) => {
                        let sym = self.interner.intern(if *b { "true" } else { "false" });
                        Some(Term::Constant(sym))
                    }
                    _ => None, // Text, Nothing not supported in predicates
                }
            }
            _ => None,
        }
    }

    pub fn process_block_headers(&mut self) {
        use crate::token::BlockType;

        while self.current < self.tokens.len() {
            if let TokenType::BlockHeader { block_type } = &self.tokens[self.current].kind {
                self.mode = match block_type {
                    BlockType::Main | BlockType::Function => ParserMode::Imperative,
                    BlockType::Theorem | BlockType::Definition | BlockType::Define | BlockType::Proof |
                    BlockType::Example | BlockType::Logic | BlockType::Note | BlockType::TypeDef |
                    BlockType::Policy | BlockType::Requires | BlockType::Axiom | BlockType::Theory |
                    BlockType::Hardware | BlockType::Property
                    | BlockType::SuspectedTypo { .. } => ParserMode::Declarative,
                    BlockType::No | BlockType::Tier => self.mode, // Annotation — keep current mode
                };
                self.current += 1;
            } else {
                break;
            }
        }
    }

    pub fn get_event_var(&mut self) -> Symbol {
        self.discourse_event_var.unwrap_or_else(|| self.interner.intern("e"))
    }

    pub fn capture_event_template(&mut self, verb: Symbol, roles: &[(ThematicRole, Term<'a>)], modifiers: &[Symbol]) {
        let non_agent_roles: Vec<_> = roles.iter()
            .filter(|(role, _)| *role != ThematicRole::Agent)
            .cloned()
            .collect();
        let agent = roles.iter()
            .find(|(role, _)| *role == ThematicRole::Agent)
            .map(|(_, t)| t.clone());
        self.last_event_template = Some(EventTemplate {
            verb,
            agent,
            non_agent_roles,
            modifiers: modifiers.to_vec(),
        });
    }

    /// A locative/circumstance relative clause headed by "where" ("the episode WHERE
    /// the survivor brought the knife"). The head `gap_var` is the LOCATION of the
    /// clause's event: parse the embedded subject + its full VP, then conjoin
    /// In(event, gap_var). The event var is the stable discourse "e" the VP builder
    /// uses, so In(e, gap) sits alongside the ∃e(...) like other event PPs.
    /// A possessive relative clause headed by "whose" ("the town WHOSE mayor is Kevin
    /// King", "the team WHOSE final score was 739"). The possessed NP belongs to the
    /// head `gap_var`; introduce it as a fresh entity m with Noun(m) ∧ Possesses(gap,
    /// m), then predicate the clause's VP over m, all under ∃m.
    pub(super) fn parse_whose_relative(&mut self, gap_var: Symbol) -> ParseResult<&'a LogicExpr<'a>> {
        self.advance(); // "whose"
        let possessed = self.parse_noun_phrase(false)?;
        let m = self.next_var_name();
        let noun_pred = self.ctx.exprs.alloc(LogicExpr::Predicate {
            name: possessed.noun,
            args: self.ctx.terms.alloc_slice([Term::Variable(m)]),
            world: None,
        });
        let possesses = self.interner.intern("Possesses");
        let poss_pred = self.ctx.exprs.alloc(LogicExpr::Predicate {
            name: possesses,
            args: self
                .ctx
                .terms
                .alloc_slice([Term::Variable(gap_var), Term::Variable(m)]),
            world: None,
        });
        let mut body = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
            left: noun_pred,
            op: TokenType::And,
            right: poss_pred,
        });
        for &adj in possessed.adjectives {
            let adj_pred = self.ctx.exprs.alloc(LogicExpr::Predicate {
                name: adj,
                args: self.ctx.terms.alloc_slice([Term::Variable(m)]),
                world: None,
            });
            body = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                left: body,
                op: TokenType::And,
                right: adj_pred,
            });
        }
        let vp = self.parse_predicate_with_subject_as_var(m)?;
        body = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
            left: body,
            op: TokenType::And,
            right: vp,
        });
        Ok(self.ctx.exprs.alloc(LogicExpr::Quantifier {
            kind: QuantifierKind::Existential,
            variable: m,
            body,
            island_id: self.current_island,
        }))
    }

    pub(super) fn parse_where_relative(&mut self, gap_var: Symbol) -> ParseResult<&'a LogicExpr<'a>> {
        self.advance(); // "where"
        // The embedded clause's own subject: a pronoun ("they"), a definite NP ("the
        // survivor"), or a proper name. A pronoun is not parsed by parse_noun_phrase,
        // so take its (capitalized) lexeme as the agent constant.
        let subj_sym = if self.check_pronoun() {
            let lex = self.interner.resolve(self.peek().lexeme).to_string();
            self.advance();
            let mut chars = lex.chars();
            let cap = match chars.next() {
                Some(f) => f.to_uppercase().collect::<String>() + chars.as_str(),
                None => lex,
            };
            self.interner.intern(&cap)
        } else {
            self.parse_noun_phrase(true)?.noun
        };
        // Bound the embedded VP at the relative-clause boundary so it does not swallow
        // an OUTER list coordinator ("the town where they met, and the city" / "…, and
        // Carol"): a comma, or an "and"/"or" that introduces a NEW NP (article / proper
        // name / quantifier), as opposed to a genuine VP coordinator ("where they met
        // and left"). Temporarily retag that token as a clause terminator while the VP
        // parses (the same boundary trick the of-pair path uses), then restore it.
        let boundary = {
            let mut found = None;
            let mut k = self.current;
            while let Some(tok) = self.tokens.get(k) {
                match &tok.kind {
                    TokenType::Comma => {
                        found = Some(k);
                        break;
                    }
                    TokenType::And | TokenType::Or
                        if matches!(
                            self.tokens.get(k + 1).map(|t| &t.kind),
                            Some(TokenType::Article(_))
                                | Some(TokenType::ProperName(_))
                                | Some(TokenType::All)
                                | Some(TokenType::Some)
                                | Some(TokenType::Any)
                                | Some(TokenType::No)
                                | Some(TokenType::Most)
                        ) =>
                    {
                        found = Some(k);
                        break;
                    }
                    TokenType::Period
                    | TokenType::EOF
                    | TokenType::Is
                    | TokenType::Are
                    | TokenType::Was
                    | TokenType::Were => break,
                    _ => k += 1,
                }
            }
            found
        };
        let saved_boundary = boundary.map(|i| (i, self.tokens[i].clone()));
        if let Some(i) = boundary {
            let span = self.tokens[i].span;
            self.tokens[i] = crate::token::Token::new(
                TokenType::Period,
                self.interner.intern("."),
                span,
            );
        }
        let inner_result = self.parse_predicate_with_subject(subj_sym);
        if let Some((i, tok)) = saved_boundary {
            self.tokens[i] = tok;
        }
        let inner = inner_result?;
        let ev = self.get_event_var();
        let loc = self.interner.intern("In");
        let loc_pred = self.ctx.exprs.alloc(LogicExpr::Predicate {
            name: loc,
            args: self
                .ctx
                .terms
                .alloc_slice([Term::Variable(ev), Term::Variable(gap_var)]),
            world: None,
        });
        Ok(self.ctx.exprs.alloc(LogicExpr::BinaryOp {
            left: inner,
            op: TokenType::And,
            right: loc_pred,
        }))
    }

    fn parse_embedded_wh_clause(&mut self) -> ParseResult<&'a LogicExpr<'a>> {
        // Parse embedded question body: "who runs", "what John ate"
        let var_name = self.interner.intern("x");
        let var_term = Term::Variable(var_name);

        if self.check_verb() {
            // "who runs" pattern
            let verb = self.consume_verb();
            let body = self.ctx.exprs.alloc(LogicExpr::Predicate {
                name: verb,
                args: self.ctx.terms.alloc_slice([var_term]),
                world: None,
            });
            return Ok(body);
        }

        if self.check_content_word() || self.check_article() {
            // "what John ate" pattern
            let subject = self.parse_noun_phrase(true)?;
            if self.check_verb() {
                let verb = self.consume_verb();
                let body = self.ctx.exprs.alloc(LogicExpr::Predicate {
                    name: verb,
                    args: self.ctx.terms.alloc_slice([
                        Term::Constant(subject.noun),
                        var_term,
                    ]),
                    world: None,
                });
                return Ok(body);
            }
        }

        // Fallback: just the wh-variable
        Ok(self.ctx.exprs.alloc(LogicExpr::Atom(var_name)))
    }

    pub fn set_pp_attachment_mode(&mut self, attach_to_noun: bool) {
        self.pp_attach_to_noun = attach_to_noun;
    }

    pub fn set_noun_priority_mode(&mut self, mode: bool) {
        self.noun_priority_mode = mode;
    }

    pub fn set_collective_mode(&mut self, mode: bool) {
        self.collective_mode = mode;
    }

    /// Force the distributive (per-member) reading of mixed verbs with
    /// definite plurals — the readings enumerator's counterpart to the
    /// default collective reading.
    pub fn set_distributive_marker(&mut self, on: bool) {
        self.distributive_marker = on;
    }

    /// Enable pragmatic enrichment (scalar implicatures, degree standards)
    /// for whole-program parses — the defeasible theorem door needs the
    /// implicature channel that the literal parse omits.
    pub fn set_pragmatic_mode(&mut self, on: bool) {
        self.pragmatic = on;
    }

    pub fn set_event_reading_mode(&mut self, mode: bool) {
        self.event_reading_mode = mode;
    }

    pub fn set_negative_scope_mode(&mut self, mode: NegativeScopeMode) {
        self.negative_scope_mode = mode;
    }

    pub fn set_modal_preference(&mut self, pref: ModalPreference) {
        self.modal_preference = pref;
    }

    fn checkpoint(&self) -> ParserCheckpoint {
        ParserCheckpoint {
            pos: self.current,
            var_counter: self.var_counter,
            bindings_len: self.donkey_bindings.len(),
            island: self.current_island,
            time: self.pending_time,
            negative_depth: self.negative_depth,
        }
    }

    fn restore(&mut self, cp: ParserCheckpoint) {
        self.current = cp.pos;
        self.var_counter = cp.var_counter;
        self.donkey_bindings.truncate(cp.bindings_len);
        self.current_island = cp.island;
        self.pending_time = cp.time;
        self.negative_depth = cp.negative_depth;
    }

    fn is_negative_context(&self) -> bool {
        self.negative_depth % 2 == 1
    }

    pub fn guard(&mut self) -> ParserGuard<'_, 'a, 'ctx, 'int> {
        ParserGuard {
            checkpoint: self.checkpoint(),
            parser: self,
            committed: false,
        }
    }

    pub(super) fn try_parse<F, T>(&mut self, op: F) -> Option<T>
    where
        F: FnOnce(&mut Self) -> ParseResult<T>,
    {
        let cp = self.checkpoint();
        match op(self) {
            Ok(res) => Some(res),
            Err(_) => {
                self.restore(cp);
                None
            }
        }
    }

    fn resolve_pronoun(&mut self, gender: Gender, number: Number) -> ParseResult<ResolvedPronoun> {
        // MODAL BARRIER: In discourse mode, try telescope FIRST if prior sentence was modal.
        // This ensures the modal barrier check runs before we search the swapped DRS.
        // The DRS contains referents from all prior sentences (merged via swap), but
        // telescope has modal filtering to block hypothetical entities from reality.
        if self.world_state.in_discourse_mode() && self.world_state.has_prior_modal_context() {
            // Only use telescope for cross-sentence reference when prior was modal
            // Telescope has modal barrier: won't return modal candidates unless we're in modal context
            if let Some(candidate) = self.world_state.resolve_via_telescope(gender) {
                return Ok(ResolvedPronoun::Variable(candidate.variable));
            }
            // Modal barrier blocked telescope resolution - pronoun can't access hypothetical entities
            // from the prior modal sentence. Check if there are ANY telescope candidates that
            // were blocked due to modal scope. If so, this is a modal barrier error.
            let blocked_candidates: Vec<_> = self.world_state.telescope_candidates()
                .iter()
                .filter(|c| c.in_modal_scope)
                .collect();
            if !blocked_candidates.is_empty() {
                // Before returning error, look ahead for modal subordinating verbs (would, could, etc.)
                // If we see one, this sentence is also modal and can access the hypothetical entity.
                let has_upcoming_modal = self.has_modal_subordination_ahead();
                if has_upcoming_modal {
                    // Modal subordination detected - allow access to the first matching candidate
                    if let Some(candidate) = blocked_candidates.into_iter().find(|c| {
                        c.gender == gender || gender == Gender::Unknown || c.gender == Gender::Unknown
                    }) {
                        return Ok(ResolvedPronoun::Variable(candidate.variable));
                    }
                }
                // There were candidates but they're all in modal scope - modal barrier blocks access
                return Err(ParseError {
                    kind: ParseErrorKind::ScopeViolation(
                        "Cannot access hypothetical entity from reality. Use modal subordination (e.g., 'would') to continue a hypothetical context.".to_string()
                    ),
                    span: self.current_span(),
                });
            }
            // No modal candidates were blocked, continue to check for same-sentence referents
        }

        // Try DRS resolution (scope-aware) for same-sentence referents
        let current_box = self.drs.current_box_index();
        match self.drs.resolve_pronoun(current_box, gender, number) {
            Ok(sym) => {
                // A rigid referent (proper name / deictic constant) denotes
                // the constant itself — "He has children." after "His
                // children…" keeps Him a constant, matching the premise.
                return Ok(if self.drs.is_rigid_referent(sym) {
                    ResolvedPronoun::Constant(sym)
                } else {
                    ResolvedPronoun::Variable(sym)
                });
            }
            Err(crate::drs::ScopeError::InaccessibleReferent { gender: g, reason, .. }) => {
                // Referent exists but is trapped in inaccessible scope.
                // In multi-sentence discourse, try telescoping first - the referent
                // from a previous sentence's conditional may be in telescope candidates.
                if self.world_state.in_discourse_mode() {
                    if let Some(candidate) = self.world_state.resolve_via_telescope(g) {
                        return Ok(ResolvedPronoun::Variable(candidate.variable));
                    }
                }
                // No telescope candidate found - this is a hard scope error
                return Err(ParseError {
                    kind: ParseErrorKind::ScopeViolation(reason),
                    span: self.current_span(),
                });
            }
            Err(crate::drs::ScopeError::NoMatchingReferent { gender: g, number: n }) => {
                // Try telescoping across sentence boundaries (if not already tried above)
                if !self.world_state.has_prior_modal_context() {
                    if let Some(candidate) = self.world_state.resolve_via_telescope(g) {
                        return Ok(ResolvedPronoun::Variable(candidate.variable));
                    }
                }

                // In discourse mode (multi-sentence context), unresolved pronouns are an error
                if self.world_state.in_discourse_mode() {
                    return Err(ParseError {
                        kind: ParseErrorKind::UnresolvedPronoun {
                            gender: g,
                            number: n,
                        },
                        span: self.current_span(),
                    });
                }

                // No prior referent - introduce deictic referent (pointing to someone in the world)
                // This handles sentences like "She told him a story" without prior discourse
                let deictic_name = match (g, n) {
                    (Gender::Male, Number::Singular) => "Him",
                    (Gender::Female, Number::Singular) => "Her",
                    (Gender::Neuter, Number::Singular) => "It",
                    (Gender::Male, Number::Plural) | (Gender::Female, Number::Plural) => "Them",
                    (Gender::Neuter, Number::Plural) => "Them",
                    (Gender::Unknown, _) => "Someone",
                };
                let sym = self.interner.intern(deictic_name);
                // Introduce the deictic as a RIGID referent (it denotes a
                // fixed individual in the world) so later pronouns resolving
                // to it also yield the constant.
                self.drs.introduce_referent_with_source(
                    sym,
                    sym,
                    g,
                    n,
                    crate::drs::ReferentSource::ProperName,
                );
                return Ok(ResolvedPronoun::Constant(sym));
            }
        }
    }

    fn resolve_donkey_pronoun(&mut self, gender: Gender) -> Option<Symbol> {
        for (noun_class, var_name, used, _wide_neg) in self.donkey_bindings.iter_mut().rev() {
            let noun_str = self.interner.resolve(*noun_class);
            let noun_gender = Self::infer_noun_gender(noun_str);
            if noun_gender == gender || gender == Gender::Neuter || noun_gender == Gender::Unknown {
                *used = true; // Mark as used by a pronoun (donkey anaphor)
                return Some(*var_name);
            }
        }
        None
    }

    fn infer_noun_gender(noun: &str) -> Gender {
        let lower = noun.to_lowercase();
        if lexicon::is_female_noun(&lower) {
            Gender::Female
        } else if lexicon::is_male_noun(&lower) {
            Gender::Male
        } else if lexicon::is_neuter_noun(&lower) {
            Gender::Neuter
        } else {
            Gender::Unknown
        }
    }

    fn is_plural_noun(noun: &str) -> bool {
        let lower = noun.to_lowercase();
        // Proper names like "Socrates", "James", "Chris" end in 's' but aren't plurals
        if lexicon::is_proper_name(&lower) {
            return false;
        }
        if lexicon::is_irregular_plural(&lower) {
            return true;
        }
        lower.ends_with('s') && !lower.ends_with("ss") && lower.len() > 2
    }

    fn singularize_noun(noun: &str) -> String {
        let lower = noun.to_lowercase();
        if let Some(singular) = lexicon::singularize(&lower) {
            return singular.to_string();
        }
        if lower.ends_with('s') && !lower.ends_with("ss") && lower.len() > 2 {
            let base = &lower[..lower.len() - 1];
            let mut chars: Vec<char> = base.chars().collect();
            if !chars.is_empty() {
                chars[0] = chars[0].to_uppercase().next().unwrap();
            }
            return chars.into_iter().collect();
        }
        let mut chars: Vec<char> = lower.chars().collect();
        if !chars.is_empty() {
            chars[0] = chars[0].to_uppercase().next().unwrap();
        }
        chars.into_iter().collect()
    }

    fn infer_gender(name: &str) -> Gender {
        let lower = name.to_lowercase();
        if lexicon::is_male_name(&lower) {
            Gender::Male
        } else if lexicon::is_female_name(&lower) {
            Gender::Female
        } else {
            Gender::Unknown
        }
    }


    /// Builds the agent term for a subject, applying metonymic coercion (§8.6):
    /// a place that conventionally denotes an institution ("the White House") is
    /// coerced to that institution when it acts — `GovernmentOf(white_house)`.
    /// Strengthens a weak scalar quantifier with its scalar implicature (§8.7): on the
    /// Horn scale ⟨some, most, many … all⟩ a weak term implicates the negation of its
    /// stronger "all" alternative. Given `Q x(R(x) ∧ S(x))` with `Q ∈ {∃, Most, Many}`,
    /// produces `Q x(R(x) ∧ S(x)) +> ¬∀x(R(x) → S(x))`. Returns `None` for a strong term
    /// ("all") or any non-scalar shape. (Open-class scalars like warm/hot would extend
    /// this through a lexicon Horn-scale; the closed-class quantifier scale is here.)
    fn scalar_implicature(&mut self, expr: &'a LogicExpr<'a>) -> Option<&'a LogicExpr<'a>> {
        if let LogicExpr::Quantifier {
            kind: QuantifierKind::Existential | QuantifierKind::Most | QuantifierKind::Many,
            variable,
            body,
            island_id,
        } = expr
        {
            // The "all" alternative: restriction implies scope, universally.
            let alt_body = if let LogicExpr::BinaryOp {
                left,
                op: TokenType::And,
                right,
            } = body
            {
                self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                    left,
                    op: TokenType::Implies,
                    right,
                })
            } else {
                body
            };
            let universal = self.ctx.exprs.alloc(LogicExpr::Quantifier {
                kind: QuantifierKind::Universal,
                variable: *variable,
                body: alt_body,
                island_id: *island_id,
            });
            let negated = self.ctx.exprs.alloc(LogicExpr::UnaryOp {
                op: TokenType::Not,
                operand: universal,
            });
            Some(self.ctx.exprs.alloc(LogicExpr::Implicature {
                assertion: expr,
                implicature: negated,
            }))
        } else {
            None
        }
    }

    fn coerce_agent(&mut self, np: &crate::ast::NounPhrase<'a>) -> Term<'a> {
        let base = self.noun_phrase_to_term(np);
        if crate::lexicon::is_institution_metonym(&self.interner.resolve(np.noun).to_lowercase()) {
            let gov = self.interner.intern("GovernmentOf");
            Term::Function(gov, self.ctx.terms.alloc_slice([base]))
        } else {
            base
        }
    }

    fn next_var_name(&mut self) -> Symbol {
        const VARS: &[&str] = &["x", "y", "z", "w", "v", "u"];
        let idx = self.var_counter;
        self.var_counter += 1;
        if idx < VARS.len() {
            self.interner.intern(VARS[idx])
        } else {
            let name = format!("x{}", idx - VARS.len() + 1);
            self.interner.intern(&name)
        }
    }

    /// Parse an INTEGER numeral lexeme EXACTLY: digit separators
    /// (`1_000_000`), radix literals (`0xff` / `0b1010` / `0o755`), and a
    /// HARD error when the value cannot fit an Int — never a silent 0.
    /// (BigInt literals ride the numeric-tower work; until then an overlong
    /// literal fails loudly.)
    fn parse_i64_numeral(&self, num_str: &str) -> ParseResult<i64> {
        self.parse_i64_numeral_signed(num_str, false)
    }

    /// The signed core: `negative` attaches the sign to the DIGITS before
    /// parsing, so `-9223372036854775808` (i64::MIN, whose magnitude alone
    /// overflows by one) parses exactly.
    fn parse_i64_numeral_signed(&self, num_str: &str, negative: bool) -> ParseResult<i64> {
        let clean = num_str.replace('_', "");
        let sign = if negative { "-" } else { "" };
        // A RADIX literal (`0x…`/`0b…`/`0o…`) denotes a BIT PATTERN, so it may use the FULL unsigned
        // 64-bit range: `0xFFFFFFFFFFFFFFFF` is the all-ones `Word64`, and a SHA-512 round constant like
        // `0xb5c0fbcfec4d3b2f` (≥ 2⁶³) is a legitimate 64-bit value. When the signed parse overflows,
        // an unsigned value in (i64::MAX, u64::MAX] reinterprets as its two's-complement i64 bits —
        // exactly what `word64(…)`/`word32(…)` read back. A DECIMAL literal is magnitude, so it stays
        // i64-bound (BigInt magnitudes ride the numeric-tower work) and still fails loudly.
        let radix = |digits: &str, base: u32| -> Result<i64, ()> {
            if let Ok(v) = i64::from_str_radix(&format!("{}{}", sign, digits), base) {
                return Ok(v);
            }
            if !negative {
                if let Ok(u) = u64::from_str_radix(digits, base) {
                    return Ok(u as i64);
                }
            }
            Err(())
        };
        let parsed = if let Some(hex) = clean.strip_prefix("0x").or_else(|| clean.strip_prefix("0X")) {
            radix(hex, 16)
        } else if let Some(bin) = clean.strip_prefix("0b").or_else(|| clean.strip_prefix("0B")) {
            radix(bin, 2)
        } else if let Some(oct) = clean.strip_prefix("0o").or_else(|| clean.strip_prefix("0O")) {
            radix(oct, 8)
        } else {
            format!("{}{}", sign, clean).parse::<i64>().map_err(|_| ())
        };
        parsed.map_err(|_| ParseError {
            kind: ParseErrorKind::ExpectedKeyword {
                keyword: format!(
                    "a representable Int literal — `{}` does not fit the Int range (±9223372036854775807)",
                    num_str
                ),
            },
            span: self.current_span(),
        })
    }

    /// True when a numeral lexeme is a RADIX literal (`0x…`/`0b…`/`0o…`) —
    /// checked BEFORE the float sniff, because `0x1E` contains an `E` that
    /// is a hex digit, not scientific notation.
    fn is_radix_numeral(num_str: &str) -> bool {
        let s = num_str.strip_prefix('_').unwrap_or(num_str);
        s.len() > 2
            && s.starts_with('0')
            && matches!(s.as_bytes()[1], b'x' | b'X' | b'b' | b'B' | b'o' | b'O')
    }

    /// Parse the NUMERAL after `item`/`items` into an index literal. An
    /// integer numeral is guarded against the 1-based footgun (`item 0` is a
    /// clean compile error); a NON-integer numeral (a float map key like
    /// `item 1.0 of prices`) is a Float literal — never the silent
    /// `unwrap_or(0)` that used to turn it into a phantom `item 0`.
    fn parse_index_numeral(&mut self, sym: Symbol) -> ParseResult<&'a Expr<'a>> {
        let num_str = self.interner.resolve(sym).to_string();
        if let Ok(n) = self.parse_i64_numeral(&num_str) {
            if n == 0 {
                return Err(ParseError {
                    kind: ParseErrorKind::ZeroIndex,
                    span: self.current_span(),
                });
            }
            return Ok(self
                .ctx
                .alloc_imperative_expr(Expr::Literal(crate::ast::Literal::Number(n))));
        }
        if let Ok(f) = num_str.parse::<f64>() {
            return Ok(self
                .ctx
                .alloc_imperative_expr(Expr::Literal(crate::ast::Literal::Float(f))));
        }
        Err(ParseError {
            kind: ParseErrorKind::ExpectedKeyword {
                keyword: format!("a numeric index (got '{}')", num_str),
            },
            span: self.current_span(),
        })
    }

    /// A fresh, user-uncollidable temporary for parser desugars ([`Stmt::Splice`]
    /// output). Shares `var_counter` so `ParserGuard` checkpoints roll it back.
    fn fresh_desugar_temp(&mut self, tag: &str) -> Symbol {
        let idx = self.var_counter;
        self.var_counter += 1;
        self.interner.intern(&format!("__{}_{}", tag, idx))
    }

    /// Lower a write into a NESTED index place — `Set item j of (item i of
    /// grid) to v` — into read → element write → write-back:
    ///
    /// ```text
    /// Let __place_i be j.  Let __place_v be v.  Let __place_k be i.
    /// Let __place_t be item __place_k of grid.
    /// Set item __place_i of __place_t to __place_v.
    /// Set item __place_k of grid to __place_t.        (recursive for depth)
    /// ```
    ///
    /// The element write targets a plain BINDING, so each engine's own
    /// copy-on-write machinery preserves value semantics (an alias of the
    /// inner row never observes the write — `diff_let_binding_isolates`); the
    /// write-back stores the possibly-fresh inner collection into the outer
    /// place. Temp order (index, value, collection) matches the engines'
    /// evaluation order for a flat `SetIndex`.
    fn desugar_place_set_index(
        &mut self,
        collection: &'a Expr<'a>,
        index: &'a Expr<'a>,
        value: &'a Expr<'a>,
    ) -> Stmt<'a> {
        let (base, key) = match collection {
            Expr::Index { collection: base, index: key } => (*base, *key),
            _ => return Stmt::SetIndex { collection, index, value },
        };
        let t_idx = self.fresh_desugar_temp("place_i");
        let t_val = self.fresh_desugar_temp("place_v");
        let t_key = self.fresh_desugar_temp("place_k");
        let t_inner = self.fresh_desugar_temp("place_t");
        let idx_ref = self.ctx.alloc_imperative_expr(Expr::Identifier(t_idx));
        let val_ref = self.ctx.alloc_imperative_expr(Expr::Identifier(t_val));
        let key_ref = self.ctx.alloc_imperative_expr(Expr::Identifier(t_key));
        let inner_ref = self.ctx.alloc_imperative_expr(Expr::Identifier(t_inner));
        let read = self.ctx.alloc_imperative_expr(Expr::Index { collection: base, index: key_ref });
        let write_back = self.desugar_place_set_index(base, key_ref, inner_ref);
        let body = [
            Stmt::Let { var: t_idx, ty: None, value: index, mutable: false },
            Stmt::Let { var: t_val, ty: None, value, mutable: false },
            Stmt::Let { var: t_key, ty: None, value: key, mutable: false },
            Stmt::Let { var: t_inner, ty: None, value: read, mutable: true },
            Stmt::SetIndex { collection: inner_ref, index: idx_ref, value: val_ref },
            write_back,
        ];
        let body = self.ctx.stmts.expect("imperative arenas not initialized")
            .alloc_slice(body.into_iter());
        Stmt::Splice { body }
    }

    /// Lower `Push v to <indexed place>` the same way (read → push into the
    /// binding → write-back). See [`Self::desugar_place_set_index`].
    fn desugar_place_push(&mut self, value: &'a Expr<'a>, collection: &'a Expr<'a>) -> Stmt<'a> {
        let (base, key) = match collection {
            Expr::Index { collection: base, index: key } => (*base, *key),
            _ => return Stmt::Push { value, collection },
        };
        let t_val = self.fresh_desugar_temp("place_v");
        let t_key = self.fresh_desugar_temp("place_k");
        let t_inner = self.fresh_desugar_temp("place_t");
        let val_ref = self.ctx.alloc_imperative_expr(Expr::Identifier(t_val));
        let key_ref = self.ctx.alloc_imperative_expr(Expr::Identifier(t_key));
        let inner_ref = self.ctx.alloc_imperative_expr(Expr::Identifier(t_inner));
        let read = self.ctx.alloc_imperative_expr(Expr::Index { collection: base, index: key_ref });
        let write_back = self.desugar_place_set_index(base, key_ref, inner_ref);
        let body = [
            Stmt::Let { var: t_val, ty: None, value, mutable: false },
            Stmt::Let { var: t_key, ty: None, value: key, mutable: false },
            Stmt::Let { var: t_inner, ty: None, value: read, mutable: true },
            Stmt::Push { value: val_ref, collection: inner_ref },
            write_back,
        ];
        let body = self.ctx.stmts.expect("imperative arenas not initialized")
            .alloc_slice(body.into_iter());
        Stmt::Splice { body }
    }

    /// Parses the token stream into a logical expression.
    ///
    /// This is the main entry point for declarative/FOL parsing. It handles
    /// multi-sentence inputs by conjoining them with logical AND, and processes
    /// various sentence types including declaratives, questions, and imperatives.
    ///
    /// # Returns
    ///
    /// An arena-allocated [`LogicExpr`] representing the parsed input, or
    /// a [`ParseError`] with source location and Socratic explanation.
    ///
    /// # Discourse State
    ///
    /// The parser maintains discourse state across sentences, enabling
    /// anaphora resolution ("he", "she", "they" refer to prior entities)
    /// and temporal coherence (tense interpretation relative to reference time).
    pub fn parse(&mut self) -> ParseResult<&'a LogicExpr<'a>> {
        let mut result = self.parse_prefix()?;

        // Postposed "while": "Y while X." mirrors the fronted "While X, Y."
        // — the condition restricts the main clause. A bare-predicate
        // condition ("… while idle") predicates over the main clause's
        // agent ("the transmitter shall not send data while [it is] idle").
        while self.check(&TokenType::While) {
            self.advance();
            let condition = if matches!(self.peek().kind, TokenType::Adjective(_))
                && matches!(
                    self.tokens.get(self.current + 1).map(|t| &t.kind),
                    Some(TokenType::Period) | Some(TokenType::EOF) | None
                ) {
                let adj = match self.advance().kind {
                    TokenType::Adjective(a) => a,
                    _ => unreachable!("guarded by the match above"),
                };
                let subject = Self::find_agent_term(result)
                    .unwrap_or(Term::Constant(self.interner.intern("System")));
                &*self.ctx.exprs.alloc(LogicExpr::Predicate {
                    name: adj,
                    args: self.ctx.terms.alloc_slice([subject]),
                    world: None,
                })
            } else {
                self.parse_sentence()?
            };
            if self.check(&TokenType::Period) {
                self.advance();
            }
            result = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                left: condition,
                op: TokenType::Implies,
                right: result,
            });
        }

        // Postposed "at any time": a universal temporal adverbial — the
        // clause is an invariant ("At most one grant is asserted at any
        // time." → G(…)).
        let at_any_time_from = if matches!(&self.peek().kind, TokenType::Preposition(p) if self.interner.resolve(*p).eq_ignore_ascii_case("at"))
            && matches!(
                self.tokens.get(self.current + 1).map(|t| &t.kind),
                Some(TokenType::Any)
            )
            && self
                .tokens
                .get(self.current + 2)
                .map(|t| {
                    self.interner
                        .resolve(t.lexeme)
                        .eq_ignore_ascii_case("time")
                })
                .unwrap_or(false)
        {
            // "… at any time."
            Some(3)
        } else if matches!(self.peek().kind, TokenType::Any)
            && self
                .tokens
                .get(self.current + 1)
                .map(|t| {
                    self.interner
                        .resolve(t.lexeme)
                        .eq_ignore_ascii_case("time")
                })
                .unwrap_or(false)
        {
            // The clause parse consumed the bare "at" as a dangling PP head;
            // "any time" remains.
            Some(2)
        } else {
            None
        };
        if let Some(n) = at_any_time_from {
            for _ in 0..n {
                self.advance();
            }
            if self.check(&TokenType::Period) {
                self.advance();
            }
            result = self.ctx.exprs.alloc(LogicExpr::Temporal {
                operator: TemporalOperator::Always,
                body: result,
            });
        }

        // A parse that stops mid-sentence is not a parse: accepting it would
        // silently drop the remainder's meaning.
        if !self.is_at_end() {
            return Err(ParseError {
                kind: crate::error::ParseErrorKind::TrailingTokens {
                    found: self.peek().kind.clone(),
                },
                span: self.current_span(),
            });
        }

        Ok(result)
    }

    /// The Agent term of the first event in an expression (used to supply
    /// the understood subject of a bare postposed condition).
    fn find_agent_term(expr: &'a LogicExpr<'a>) -> Option<Term<'a>> {
        match expr {
            LogicExpr::NeoEvent(data) => data
                .roles
                .iter()
                .find(|(role, _)| matches!(role, crate::ast::ThematicRole::Agent))
                .map(|(_, term)| term.clone()),
            LogicExpr::Modal { operand, .. } => Self::find_agent_term(operand),
            LogicExpr::UnaryOp { operand, .. } => Self::find_agent_term(operand),
            LogicExpr::Temporal { body, .. } => Self::find_agent_term(body),
            LogicExpr::Aspectual { body, .. } => Self::find_agent_term(body),
            LogicExpr::Quantifier { body, .. } => Self::find_agent_term(body),
            LogicExpr::BinaryOp { left, right, .. } => {
                Self::find_agent_term(left).or_else(|| Self::find_agent_term(right))
            }
            _ => None,
        }
    }

    /// Parses a maximal declarative prefix WITHOUT requiring end-of-input.
    ///
    /// For embedded sub-parses whose end is marked by a host-grammar keyword
    /// the caller checks itself ("Trust ⟨proposition⟩ because …"). Whole-input
    /// parsing must use [`Self::parse`], which rejects trailing tokens.
    pub(super) fn parse_prefix(&mut self) -> ParseResult<&'a LogicExpr<'a>> {
        let mut result = self.parse_sentence()?;

        // Loop: handle ANY number of additional sentences (unlimited)
        // Handle all sentence terminators: . ? !
        while self.check(&TokenType::Period) || self.check(&TokenType::Exclamation) {
            self.advance(); // consume terminator
            if !self.is_at_end() {
                let next = self.parse_sentence()?;
                result = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                    left: result,
                    op: TokenType::And,
                    right: next,
                });
            }
        }

        Ok(result)
    }

    /// Parses with pragmatic enrichment: the truth-conditional parse PLUS scalar
    /// implicature (§8.7). The literal `parse()` is unchanged; here a leading weak
    /// scalar "some" is strengthened to `∃… +> ¬∀…`. Used by the pragmatic compile
    /// path so the implicature appears as a separate labeled component.
    pub fn parse_pragmatic(&mut self) -> ParseResult<&'a LogicExpr<'a>> {
        self.pragmatic = true;
        // A leading weak scalar quantifier (some / most / many) is the Horn-scale trigger;
        // its stronger "all" alternative is implicated. "all" is not a trigger.
        let scalar_trigger = matches!(
            self.peek().kind,
            TokenType::Some | TokenType::Most | TokenType::Many
        );
        let result = self.parse()?;
        if scalar_trigger {
            if let Some(strengthened) = self.scalar_implicature(result) {
                return Ok(strengthened);
            }
        }
        Ok(result)
    }

    /// Parses a LOGOS program into a list of statements.
    ///
    /// This is the main entry point for imperative/executable LOGOS code.
    /// It handles block structures (Definition, Policy, Procedure, Theorem),
    /// function definitions, type definitions, and executable statements.
    ///
    /// # Returns
    ///
    /// A vector of arena-allocated [`Stmt`] representing the program, or
    /// a [`ParseError`] with source location and Socratic explanation.
    ///
    /// # Block Types
    ///
    /// - **Definition**: Type definitions (structs, enums, generics)
    /// - **Policy**: Security predicates and capability rules
    /// - **Procedure**: Executable code blocks
    /// - **Theorem**: Logical propositions with proof strategies
    pub fn parse_program(&mut self) -> ParseResult<Vec<Stmt<'a>>> {
        let mut statements = Vec::new();
        self.stmt_spans.clear();
        let mut in_definition_block = false;
        let mut pending_opt_flags = OptimizationConfig::all_on();

        // Check if we started in a Definition block (from process_block_headers)
        if self.mode == ParserMode::Declarative {
            // Check if the previous token was a Definition header
            // For now, assume Definition blocks should be skipped
            // We'll detect them by checking the content pattern
        }

        while !self.is_at_end() {
            // Handle block headers
            if let Some(Token { kind: TokenType::BlockHeader { block_type }, .. }) = self.tokens.get(self.current) {
                match block_type {
                    BlockType::SuspectedTypo { found, suggestion } => {
                        let found = self.interner.resolve(*found).to_string();
                        let suggestion_str = self.interner.resolve(*suggestion);
                        let mut canonical: String = suggestion_str.to_string();
                        if let Some(c) = canonical.get_mut(0..1) {
                            c.make_ascii_uppercase();
                        }
                        return Err(ParseError {
                            kind: ParseErrorKind::ExpectedKeyword {
                                keyword: format!(
                                    "a known header — `## {}` looks like a typo of `## {}` (if it is a prose heading, pick a name further from the code headers)",
                                    found, canonical
                                ),
                            },
                            span: self.current_span(),
                        });
                    }
                    BlockType::Definition => {
                        in_definition_block = true;
                        self.mode = ParserMode::Declarative;
                        self.advance();
                        continue;
                    }
                    BlockType::Main => {
                        // A `## No <X>` before `## Main` (not attached to a function)
                        // is a FILE-LEVEL decorator: fold it into the program config.
                        self.program_opt_flags =
                            self.program_opt_flags.merged(&pending_opt_flags);
                        pending_opt_flags = OptimizationConfig::all_on();
                        in_definition_block = false;
                        self.mode = ParserMode::Imperative;
                        self.advance();
                        continue;
                    }
                    BlockType::No => {
                        // Optimization annotation: `## No <Keyword>` clears that
                        // optimization for the following function; `## No Optimize`
                        // clears all of them. Keywords come from the registry.
                        self.advance(); // consume the `## No` header
                        if let Some(token) = self.tokens.get(self.current) {
                            let word = self.interner.resolve(token.lexeme).to_lowercase();
                            if word == "optimize" {
                                pending_opt_flags = OptimizationConfig::all_off();
                            } else if let Some(opt) = by_keyword(&word) {
                                pending_opt_flags.set(opt, false);
                            }
                            // Unknown annotation — ignore silently.
                            self.advance(); // consume the flag word
                        }
                        while self.check(&TokenType::Newline) {
                            self.advance();
                        }
                        continue;
                    }
                    BlockType::Tier => {
                        // Tiered-optimizer pin: `## Tier <opt> <eager|t1|t2|t3|never>`
                        // overrides the hotness tier at which that optimization runs.
                        // Program-wide (governs the whole program's tiering ladder),
                        // collected directly — no per-function pending state.
                        self.advance(); // consume the `## Tier` header
                        let kw = self
                            .tokens
                            .get(self.current)
                            .map(|t| self.interner.resolve(t.lexeme).to_lowercase());
                        if kw.is_some() {
                            self.advance(); // consume the optimization keyword
                        }
                        let val = self
                            .tokens
                            .get(self.current)
                            .map(|t| self.interner.resolve(t.lexeme).to_lowercase());
                        if val.is_some() {
                            self.advance(); // consume the tier value
                        }
                        if let (Some(kw), Some(val)) = (kw, val) {
                            if let (Some(opt), Some(pin)) = (by_keyword(&kw), pin_from_str(&val)) {
                                self.program_tier_pins.set(opt, pin);
                            }
                            // Unknown opt / value — ignore silently.
                        }
                        while self.check(&TokenType::Newline) {
                            self.advance();
                        }
                        continue;
                    }
                    BlockType::Function => {
                        in_definition_block = false;
                        self.mode = ParserMode::Imperative;
                        let header_tok = self.current;
                        self.advance();
                        // Parse function definition, passing pending annotations
                        let flags = std::mem::take(&mut pending_opt_flags);
                        let func_def = self.parse_function_def_with_flags(flags)?;
                        statements.push(func_def);
                        self.record_stmt_span(header_tok);
                        continue;
                    }
                    BlockType::TypeDef => {
                        // Type definitions are handled by DiscoveryPass
                        // Skip content until next block header
                        self.advance();
                        self.skip_type_def_content();
                        continue;
                    }
                    BlockType::Policy => {
                        // Phase 50: Policy definitions are handled by DiscoveryPass
                        // Skip content until next block header
                        in_definition_block = true;  // Reuse flag to skip content
                        self.mode = ParserMode::Declarative;
                        self.advance();
                        continue;
                    }
                    BlockType::Hardware | BlockType::Property => {
                        // Hardware signal declarations and temporal property assertions
                        // Skip content until next block header
                        in_definition_block = true;
                        self.mode = ParserMode::Declarative;
                        self.advance();
                        continue;
                    }
                    BlockType::Theorem => {
                        // Phase 63: Parse theorem block
                        in_definition_block = false;
                        self.mode = ParserMode::Declarative;
                        let header_tok = self.current;
                        self.advance();
                        let theorem = self.parse_theorem_block()?;
                        statements.push(theorem);
                        self.record_stmt_span(header_tok);
                        continue;
                    }
                    BlockType::Define => {
                        // Rung 0a: vernacular-logic predicate definition.
                        in_definition_block = false;
                        self.mode = ParserMode::Declarative;
                        let header_tok = self.current;
                        self.advance();
                        let definition = self.parse_define_block()?;
                        statements.push(definition);
                        self.record_stmt_span(header_tok);
                        continue;
                    }
                    BlockType::Axiom => {
                        // A named formal first-order axiom (the seam for Tarski).
                        in_definition_block = false;
                        self.mode = ParserMode::Declarative;
                        let header_tok = self.current;
                        self.advance();
                        let axiom = self.parse_axiom_block()?;
                        statements.push(axiom);
                        self.record_stmt_span(header_tok);
                        continue;
                    }
                    BlockType::Theory => {
                        // A named development grouping formal axioms and theorems.
                        in_definition_block = false;
                        self.mode = ParserMode::Declarative;
                        let header_tok = self.current;
                        self.advance();
                        let theory = self.parse_theory_block()?;
                        statements.push(theory);
                        self.record_stmt_span(header_tok);
                        continue;
                    }
                    BlockType::Requires => {
                        in_definition_block = false;
                        self.mode = ParserMode::Declarative;
                        let header_tok = self.current;
                        self.advance();
                        let deps = self.parse_requires_block()?;
                        for _ in 0..deps.len() {
                            self.record_stmt_span(header_tok);
                        }
                        statements.extend(deps);
                        continue;
                    }
                    _ => {
                        // Skip other declarative blocks (Proof, Example, Logic, Note)
                        in_definition_block = false;
                        self.mode = ParserMode::Declarative;
                        self.advance();
                        continue;
                    }
                }
            }

            // Skip Definition block content - handled by DiscoveryPass
            if in_definition_block {
                self.advance();
                continue;
            }

            // Skip indent/dedent/newline tokens at program level
            if self.check(&TokenType::Indent) || self.check(&TokenType::Dedent) || self.check(&TokenType::Newline) {
                self.advance();
                continue;
            }

            // In imperative mode, parse statements
            if self.mode == ParserMode::Imperative {
                // `Accept computed <Name> where <param> is an Int from <lo> to <hi>` is a
                // pure parse-time contract declaration — it records the named bounds and
                // emits NO runtime statement (a later `Run … under <Name>` inlines them).
                if self.check_word("Accept") {
                    self.parse_accept_contract()?;
                    continue;
                }
                let start_tok = self.current;
                let stmt = self.parse_statement()?;
                statements.push(stmt);

                if self.check(&TokenType::Period) {
                    self.advance();
                }
                self.record_stmt_span(start_tok);
            } else {
                // In declarative mode (Theorem, etc.), skip for now
                self.advance();
            }
        }

        // Any decorators not consumed by a function (trailing, or a library with
        // no `## Main`) are file-level.
        self.program_opt_flags = self.program_opt_flags.merged(&pending_opt_flags);
        debug_assert_eq!(
            self.stmt_spans.len(),
            statements.len(),
            "stmt_spans must stay aligned 1:1 with the statement list"
        );

        // The AST depth gate: "parsed ⇒ bounded". Any tree this function
        // returns is safe for every downstream recursive walker — deep
        // chains built iteratively above are caught here; deep parse-time
        // recursion (parenthesis towers) is caught by `recursion_depth`.
        crate::ast_depth::validate_program_depth(
            &statements,
            self.stmt_spans.first().copied().unwrap_or_else(|| self.current_span()),
        )?;

        Ok(statements)
    }

    /// Enter one level of imperative parse recursion, erroring gracefully at
    /// the depth limit (the parse-time half of the AST depth gate). Pair
    /// every call with [`Parser::leave_recursion`].
    pub(super) fn enter_recursion(&mut self) -> ParseResult<()> {
        self.recursion_depth += 1;
        let limit = crate::ast_depth::max_parse_recursion();
        if self.recursion_depth > limit {
            self.recursion_depth -= 1;
            return Err(ParseError {
                kind: ParseErrorKind::AstTooDeep { depth: limit + 1, max_depth: limit },
                span: self.current_span(),
            });
        }
        Ok(())
    }

    /// Leave one level of imperative parse recursion.
    pub(super) fn leave_recursion(&mut self) {
        self.recursion_depth = self.recursion_depth.saturating_sub(1);
    }

    /// The program-wide optimization config from file-level `## No <X>` decorators
    /// (all-on minus the file-level disables). The compile entry combines this with
    /// `from_env` and per-function flags.
    pub fn program_opt_flags(&self) -> OptimizationConfig {
        self.program_opt_flags
    }

    /// The program-wide tiered-optimizer pins from file-level `## Tier <opt> <value>`
    /// decorators (HOTSWAP §8). The run-path engine overlays these onto the env
    /// [`crate::optimization::HotswapConfig`] before optimizing.
    pub fn program_tier_pins(&self) -> PinSet {
        self.program_tier_pins
    }

    /// Depth-guarded wrapper: every nested construct (If/While/Repeat/Zone
    /// bodies, however each parses its block) recurses through here, so one
    /// guard covers all statement nesting. Flat statement lists enter and
    /// leave pairwise — sequential code never accumulates depth.
    fn parse_statement(&mut self) -> ParseResult<Stmt<'a>> {
        self.enter_recursion()?;
        let result = self.parse_statement_inner();
        self.leave_recursion();
        result
    }

    fn parse_statement_inner(&mut self) -> ParseResult<Stmt<'a>> {
        // Phase 32: Function definitions can appear inside Main block
        // Handle both TokenType::To and Preposition("to")
        if self.check(&TokenType::To) || self.check_preposition_is("to") {
            return self.parse_function_def();
        }
        if self.check(&TokenType::Let) {
            return self.parse_let_statement();
        }
        // Phase 23b: Equals-style assignment with explicit `mut` keyword
        // Syntax: `mut x = 5` or `mut x: Int = 5`
        if self.check(&TokenType::Mut) {
            return self.parse_equals_assignment(true);
        }
        // Phase 23b: Equals-style assignment (identifier = value)
        // Syntax: `x = 5` or `x: Int = 5`
        if self.peek_equals_assignment() {
            return self.parse_equals_assignment(false);
        }
        // Compound assignment: `x += e`, `grid[i] *= 2`, `p.count += 1`.
        if self.peek_compound_assignment() {
            return self.parse_compound_assignment();
        }
        if self.check(&TokenType::Set) {
            return self.parse_set_statement();
        }
        if self.check(&TokenType::Return) {
            return self.parse_return_statement();
        }
        if self.check(&TokenType::Break) {
            return self.parse_break_statement();
        }
        if self.check(&TokenType::If) {
            return self.parse_if_statement();
        }
        if self.check(&TokenType::Assert) {
            return self.parse_assert_statement();
        }
        if self.check(&TokenType::Require) {
            return self.parse_require_statement();
        }
        // Phase 35: Trust statement
        if self.check(&TokenType::Trust) {
            return self.parse_trust_statement();
        }
        // Phase 50: Security Check statement
        if self.check(&TokenType::Check) {
            return self.parse_check_statement();
        }
        // Phase 51: P2P Networking statements
        if self.check(&TokenType::Listen) {
            return self.parse_listen_statement();
        }
        if self.check(&TokenType::NetConnect) {
            return self.parse_connect_statement();
        }
        if self.check(&TokenType::Sleep) {
            return self.parse_sleep_statement();
        }
        // `Run <f> on <arg> under <Name> into <var>` — invoke a shipped computation through a
        // named acceptance contract; desugars to `Let <var> be run_accepted(<f>, <arg>, lo, hi)`.
        if self.check_word("Run") {
            return self.parse_run_under_contract();
        }
        // Phase 52: GossipSub sync statement
        if self.check(&TokenType::Sync) {
            return self.parse_sync_statement();
        }
        // Phase 53: Persistent storage mount statement
        if self.check(&TokenType::Mount) {
            return self.parse_mount_statement();
        }
        if self.check(&TokenType::While) {
            return self.parse_while_statement();
        }
        if self.check(&TokenType::Repeat) {
            return self.parse_repeat_statement();
        }
        // Phase 30b: Allow "for" without "Repeat" keyword
        if self.check(&TokenType::For) {
            return self.parse_for_statement();
        }
        if self.check(&TokenType::Call) {
            return self.parse_call_statement();
        }
        if self.check(&TokenType::Give) {
            return self.parse_give_statement();
        }
        if self.check(&TokenType::Show) {
            return self.parse_show_statement();
        }
        // Phase 33: Pattern matching on sum types
        if self.check(&TokenType::Inspect) {
            return self.parse_inspect_statement();
        }

        // Phase 43D: Collection operations
        if self.check(&TokenType::Push) {
            return self.parse_push_statement();
        }
        if self.check(&TokenType::Pop) {
            return self.parse_pop_statement();
        }
        // Set operations
        if self.check(&TokenType::Add) {
            return self.parse_add_statement();
        }
        if self.check(&TokenType::Remove) {
            return self.parse_remove_statement();
        }

        // Phase 8.5: Memory zone block
        if self.check(&TokenType::Inside) {
            return self.parse_zone_statement();
        }

        // Phase 9: Structured Concurrency blocks
        if self.check(&TokenType::Attempt) {
            return self.parse_concurrent_block();
        }
        if self.check(&TokenType::Simultaneously) {
            return self.parse_parallel_block();
        }

        // Phase 10: IO statements
        if self.check(&TokenType::Read) {
            return self.parse_read_statement();
        }
        if self.check(&TokenType::Write) {
            return self.parse_write_statement();
        }

        // Phase 46: Agent System statements
        if self.check(&TokenType::Spawn) {
            return self.parse_spawn_statement();
        }
        if self.check_word("Stream") {
            return self.parse_stream_statement();
        }
        if self.check(&TokenType::Send) {
            // Phase 54: Disambiguate "Send x into pipe" vs "Send x to agent"
            if self.lookahead_contains_into() {
                return self.parse_send_pipe_statement();
            }
            return self.parse_send_statement();
        }
        if self.check(&TokenType::Await) {
            // Phase 54: Disambiguate "Await the first of:" vs "Await response from agent"
            if self.lookahead_is_first_of() {
                return self.parse_select_statement();
            }
            return self.parse_await_statement();
        }

        // Phase 49: CRDT statements
        if self.check(&TokenType::Merge) {
            return self.parse_merge_statement();
        }
        if self.check(&TokenType::Increase) {
            return self.parse_increase_statement();
        }
        // Phase 49b: Extended CRDT statements
        if self.check(&TokenType::Decrease) {
            return self.parse_decrease_statement();
        }
        if self.check(&TokenType::Append) {
            return self.parse_append_statement();
        }
        if self.check(&TokenType::Resolve) {
            return self.parse_resolve_statement();
        }

        // Phase 54: Go-like Concurrency statements
        if self.check(&TokenType::Launch) {
            return self.parse_launch_statement();
        }
        if self.check(&TokenType::Stop) {
            return self.parse_stop_statement();
        }
        if self.check(&TokenType::Try) {
            return self.parse_try_statement();
        }
        if self.check(&TokenType::Receive) {
            return self.parse_receive_pipe_statement();
        }

        // Escape hatch: raw foreign code blocks
        if self.check(&TokenType::Escape) {
            return self.parse_escape_statement();
        }

        // Expression-statement: function call without "Call" keyword
        // e.g., `greet("Alice").` instead of `Call greet with "Alice".`
        // Check if next token is LParen (indicating a function call)
        if self.tokens.get(self.current + 1)
            .map(|t| matches!(t.kind, TokenType::LParen))
            .unwrap_or(false)
        {
            // Get the function name from current token
            let function = self.peek().lexeme;
            self.advance(); // consume function name

            // Parse the call expression (starts from LParen)
            let expr = self.parse_call_expr(function)?;
            if let Expr::Call { function, args } = expr {
                return Ok(Stmt::Call { function: *function, args: args.clone() });
            }
        }

        // `x is 5.` at statement position: value comparison spelled with the
        // predicate copula. Diagnose it specifically — a generic
        // ExpectedStatement would bury the actual lesson (say `equals`).
        // Only literal values qualify: `x is even.` is predication, not a
        // botched comparison.
        if self
            .tokens
            .get(self.current + 1)
            .is_some_and(|t| matches!(t.kind, TokenType::Is))
        {
            if let Some(value_token) = self.tokens.get(self.current + 2) {
                if matches!(
                    value_token.kind,
                    TokenType::Number(_)
                        | TokenType::StringLiteral(_)
                        | TokenType::InterpolatedString(_)
                ) {
                    let variable = self.interner.resolve(self.peek().lexeme).to_string();
                    let value = self.interner.resolve(value_token.lexeme).to_string();
                    let span = Span::new(self.peek().span.start, value_token.span.end);
                    return Err(ParseError {
                        kind: ParseErrorKind::IsValueEquality { variable, value },
                        span,
                    });
                }
            }
        }

        Err(ParseError {
            kind: ParseErrorKind::ExpectedStatement,
            span: self.current_span(),
        })
    }

    fn parse_if_statement(&mut self) -> ParseResult<Stmt<'a>> {
        self.advance(); // consume "If"

        // Parse condition expression (simple: identifier equals value)
        let cond = self.parse_condition()?;

        // Optionally consume "then" before the colon (supports "If x = 5 then:" syntax)
        if self.check(&TokenType::Then) {
            self.advance();
        }

        // Expect colon
        if !self.check(&TokenType::Colon) {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: ":".to_string() },
                span: self.current_span(),
            });
        }
        self.advance(); // consume ":"

        // Parse the then body — an indented block, OR (inline guard) a single
        // statement on the same line: `If c: Return 1.`
        let mut then_stmts = Vec::new();
        if self.check(&TokenType::Indent) {
            self.advance(); // consume Indent
            while !self.check(&TokenType::Dedent) && !self.is_at_end() {
                let stmt = self.parse_statement()?;
                then_stmts.push(stmt);
                if self.check(&TokenType::Period) {
                    self.advance();
                }
            }
            if self.check(&TokenType::Dedent) {
                self.advance();
            }
        } else {
            let stmt = self.parse_statement()?;
            then_stmts.push(stmt);
            if self.check(&TokenType::Period) {
                self.advance();
            }
        }

        // Allocate then_block in arena
        let then_block = self.ctx.stmts.expect("imperative arenas not initialized")
            .alloc_slice(then_stmts.into_iter());

        // Check for else clause: Otherwise/Else/Otherwise If/Else If/elif
        let else_block = if self.check(&TokenType::Otherwise) || self.check(&TokenType::Else) {
            self.advance(); // consume "Otherwise" or "Else"

            // Check for "Otherwise If" / "Else If" chain
            if self.check(&TokenType::If) {
                // Parse as else-if: create single-statement else block containing nested If
                let nested_if = self.parse_if_statement()?;
                let nested_slice = self.ctx.stmts.expect("imperative arenas not initialized")
                    .alloc_slice(std::iter::once(nested_if));
                Some(nested_slice)
            } else {
                // Regular else block - expect colon and indent
                if !self.check(&TokenType::Colon) {
                    return Err(ParseError {
                        kind: ParseErrorKind::ExpectedKeyword { keyword: ":".to_string() },
                        span: self.current_span(),
                    });
                }
                self.advance(); // consume ":"

                // Indented block OR inline: `Otherwise: Show "x".`
                let mut else_stmts = Vec::new();
                if self.check(&TokenType::Indent) {
                    self.advance(); // consume Indent
                    while !self.check(&TokenType::Dedent) && !self.is_at_end() {
                        let stmt = self.parse_statement()?;
                        else_stmts.push(stmt);
                        if self.check(&TokenType::Period) {
                            self.advance();
                        }
                    }
                    if self.check(&TokenType::Dedent) {
                        self.advance();
                    }
                } else {
                    let stmt = self.parse_statement()?;
                    else_stmts.push(stmt);
                    if self.check(&TokenType::Period) {
                        self.advance();
                    }
                }

                Some(self.ctx.stmts.expect("imperative arenas not initialized")
                    .alloc_slice(else_stmts.into_iter()))
            }
        } else if self.check(&TokenType::Elif) {
            // Python-style elif: equivalent to "Else If"
            self.advance(); // consume "elif"
            // Parse the condition and body directly (elif acts like "Else If" without the separate If token)
            let nested_if = self.parse_elif_as_if()?;
            let nested_slice = self.ctx.stmts.expect("imperative arenas not initialized")
                .alloc_slice(std::iter::once(nested_if));
            Some(nested_slice)
        } else {
            None
        };

        Ok(Stmt::If {
            cond,
            then_block,
            else_block,
        })
    }

    /// Parse an elif clause as an if statement.
    /// Called after "elif" has been consumed - parses condition and body directly.
    fn parse_elif_as_if(&mut self) -> ParseResult<Stmt<'a>> {
        // Parse condition expression (elif is already consumed)
        let cond = self.parse_condition()?;

        // Expect colon
        if !self.check(&TokenType::Colon) {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: ":".to_string() },
                span: self.current_span(),
            });
        }
        self.advance(); // consume ":"

        // Parse the then body — an indented block, OR (inline guard) a single
        // statement on the same line: `If c: Return 1.`
        let mut then_stmts = Vec::new();
        if self.check(&TokenType::Indent) {
            self.advance(); // consume Indent
            while !self.check(&TokenType::Dedent) && !self.is_at_end() {
                let stmt = self.parse_statement()?;
                then_stmts.push(stmt);
                if self.check(&TokenType::Period) {
                    self.advance();
                }
            }
            if self.check(&TokenType::Dedent) {
                self.advance();
            }
        } else {
            let stmt = self.parse_statement()?;
            then_stmts.push(stmt);
            if self.check(&TokenType::Period) {
                self.advance();
            }
        }

        // Allocate then_block in arena
        let then_block = self.ctx.stmts.expect("imperative arenas not initialized")
            .alloc_slice(then_stmts.into_iter());

        // Check for else clause: Otherwise/Else/Otherwise If/Else If/elif
        let else_block = if self.check(&TokenType::Otherwise) || self.check(&TokenType::Else) {
            self.advance(); // consume "Otherwise" or "Else"

            // Check for "Otherwise If" / "Else If" chain
            if self.check(&TokenType::If) {
                let nested_if = self.parse_if_statement()?;
                let nested_slice = self.ctx.stmts.expect("imperative arenas not initialized")
                    .alloc_slice(std::iter::once(nested_if));
                Some(nested_slice)
            } else {
                // Regular else block
                if !self.check(&TokenType::Colon) {
                    return Err(ParseError {
                        kind: ParseErrorKind::ExpectedKeyword { keyword: ":".to_string() },
                        span: self.current_span(),
                    });
                }
                self.advance(); // consume ":"

                // Indented block OR inline: `Otherwise: Show "x".`
                let mut else_stmts = Vec::new();
                if self.check(&TokenType::Indent) {
                    self.advance(); // consume Indent
                    while !self.check(&TokenType::Dedent) && !self.is_at_end() {
                        let stmt = self.parse_statement()?;
                        else_stmts.push(stmt);
                        if self.check(&TokenType::Period) {
                            self.advance();
                        }
                    }
                    if self.check(&TokenType::Dedent) {
                        self.advance();
                    }
                } else {
                    let stmt = self.parse_statement()?;
                    else_stmts.push(stmt);
                    if self.check(&TokenType::Period) {
                        self.advance();
                    }
                }

                Some(self.ctx.stmts.expect("imperative arenas not initialized")
                    .alloc_slice(else_stmts.into_iter()))
            }
        } else if self.check(&TokenType::Elif) {
            self.advance(); // consume "elif"
            let nested_if = self.parse_elif_as_if()?;
            let nested_slice = self.ctx.stmts.expect("imperative arenas not initialized")
                .alloc_slice(std::iter::once(nested_if));
            Some(nested_slice)
        } else {
            None
        };

        Ok(Stmt::If {
            cond,
            then_block,
            else_block,
        })
    }

    fn parse_while_statement(&mut self) -> ParseResult<Stmt<'a>> {
        self.advance(); // consume "While"

        let cond = self.parse_condition()?;

        // Phase 44: Parse optional (decreasing expr)
        let decreasing = if self.check(&TokenType::LParen) {
            self.advance(); // consume '('

            // Expect "decreasing" keyword
            if !self.check_word("decreasing") {
                return Err(ParseError {
                    kind: ParseErrorKind::ExpectedKeyword { keyword: "decreasing".to_string() },
                    span: self.current_span(),
                });
            }
            self.advance(); // consume "decreasing"

            let variant = self.parse_imperative_expr()?;

            if !self.check(&TokenType::RParen) {
                return Err(ParseError {
                    kind: ParseErrorKind::ExpectedKeyword { keyword: ")".to_string() },
                    span: self.current_span(),
                });
            }
            self.advance(); // consume ')'

            Some(variant)
        } else {
            None
        };

        if !self.check(&TokenType::Colon) {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: ":".to_string() },
                span: self.current_span(),
            });
        }
        self.advance(); // consume ":"

        if !self.check(&TokenType::Indent) {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedStatement,
                span: self.current_span(),
            });
        }
        self.advance(); // consume Indent

        let mut body_stmts = Vec::new();
        while !self.check(&TokenType::Dedent) && !self.is_at_end() {
            let stmt = self.parse_statement()?;
            body_stmts.push(stmt);
            if self.check(&TokenType::Period) {
                self.advance();
            }
        }

        if self.check(&TokenType::Dedent) {
            self.advance();
        }

        let body = self.ctx.stmts.expect("imperative arenas not initialized")
            .alloc_slice(body_stmts.into_iter());

        Ok(Stmt::While { cond, body, decreasing })
    }

    /// Parse a loop pattern: single identifier or tuple destructuring.
    /// Examples: `x` or `(k, v)` or `(a, b, c)`
    fn parse_loop_pattern(&mut self) -> ParseResult<Pattern> {
        use crate::ast::stmt::Pattern;

        // Check for tuple pattern: (x, y, ...)
        if self.check(&TokenType::LParen) {
            self.advance(); // consume "("

            let mut identifiers = Vec::new();
            loop {
                let id = self.expect_identifier()?;
                identifiers.push(id);

                // Check for comma to continue
                if self.check(&TokenType::Comma) {
                    self.advance(); // consume ","
                    continue;
                }
                break;
            }

            // Expect closing paren
            if !self.check(&TokenType::RParen) {
                return Err(ParseError {
                    kind: ParseErrorKind::ExpectedKeyword { keyword: ")".to_string() },
                    span: self.current_span(),
                });
            }
            self.advance(); // consume ")"

            Ok(Pattern::Tuple(identifiers))
        } else {
            // Single identifier pattern
            let id = self.expect_identifier()?;
            Ok(Pattern::Identifier(id))
        }
    }

    fn parse_repeat_statement(&mut self) -> ParseResult<Stmt<'a>> {
        self.advance(); // consume "Repeat"

        // `Repeat forever:` — an infinite loop (exit via `Break`), lowered to `While true:`.
        if self.check_word("forever") {
            self.advance(); // consume "forever"
            if !self.check(&TokenType::Colon) {
                return Err(ParseError { kind: ParseErrorKind::ExpectedKeyword { keyword: ":".to_string() }, span: self.current_span() });
            }
            self.advance(); // consume ":"
            if !self.check(&TokenType::Indent) {
                return Err(ParseError { kind: ParseErrorKind::ExpectedStatement, span: self.current_span() });
            }
            self.advance(); // consume Indent
            let mut body_stmts = Vec::new();
            while !self.check(&TokenType::Dedent) && !self.is_at_end() {
                let stmt = self.parse_statement()?;
                body_stmts.push(stmt);
                if self.check(&TokenType::Period) { self.advance(); }
            }
            if self.check(&TokenType::Dedent) { self.advance(); }
            let body = self.ctx.stmts.expect("imperative arenas not initialized").alloc_slice(body_stmts.into_iter());
            let cond = self.ctx.alloc_imperative_expr(Expr::Literal(crate::ast::Literal::Boolean(true)));
            return Ok(Stmt::While { cond, body, decreasing: None });
        }

        // Optional "for"
        if self.check(&TokenType::For) {
            self.advance();
        }

        // Parse loop pattern: single identifier or tuple destructuring
        let pattern = self.parse_loop_pattern()?;

        // Determine iteration type: "in" for collection, "from" for range
        let iterable = if self.check(&TokenType::From) || self.check_preposition_is("from") {
            self.advance(); // consume "from"
            let start = self.parse_imperative_expr()?;

            // Expect "to" (can be keyword or preposition)
            if !self.check(&TokenType::To) && !self.check_preposition_is("to") {
                return Err(ParseError {
                    kind: ParseErrorKind::ExpectedKeyword { keyword: "to".to_string() },
                    span: self.current_span(),
                });
            }
            self.advance();

            let end = self.parse_imperative_expr()?;
            self.ctx.alloc_imperative_expr(Expr::Range { start, end })
        } else if self.check(&TokenType::In) || self.check_preposition_is("in") {
            self.advance(); // consume "in"
            self.parse_imperative_expr()?
        } else {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "in or from".to_string() },
                span: self.current_span(),
            });
        };

        // Expect colon
        if !self.check(&TokenType::Colon) {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: ":".to_string() },
                span: self.current_span(),
            });
        }
        self.advance();

        // Expect indent
        if !self.check(&TokenType::Indent) {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedStatement,
                span: self.current_span(),
            });
        }
        self.advance();

        // Parse body statements
        let mut body_stmts = Vec::new();
        while !self.check(&TokenType::Dedent) && !self.is_at_end() {
            let stmt = self.parse_statement()?;
            body_stmts.push(stmt);
            if self.check(&TokenType::Period) {
                self.advance();
            }
        }

        if self.check(&TokenType::Dedent) {
            self.advance();
        }

        let body = self.ctx.stmts.expect("imperative arenas not initialized")
            .alloc_slice(body_stmts.into_iter());

        Ok(Stmt::Repeat { pattern, iterable, body })
    }

    /// Parse a for-loop without the "Repeat" keyword prefix.
    /// Syntax: `for <var> from <start> to <end>:` or `for <var> in <collection>:`
    fn parse_for_statement(&mut self) -> ParseResult<Stmt<'a>> {
        self.advance(); // consume "for"

        // Parse loop pattern: single identifier or tuple destructuring
        let pattern = self.parse_loop_pattern()?;

        // Determine iteration type: "in" for collection, "from" for range
        let iterable = if self.check(&TokenType::From) || self.check_preposition_is("from") {
            self.advance(); // consume "from"
            let start = self.parse_imperative_expr()?;

            // Expect "to" (can be keyword or preposition)
            if !self.check(&TokenType::To) && !self.check_preposition_is("to") {
                return Err(ParseError {
                    kind: ParseErrorKind::ExpectedKeyword { keyword: "to".to_string() },
                    span: self.current_span(),
                });
            }
            self.advance();

            let end = self.parse_imperative_expr()?;
            self.ctx.alloc_imperative_expr(Expr::Range { start, end })
        } else if self.check(&TokenType::In) || self.check_preposition_is("in") {
            self.advance(); // consume "in"
            self.parse_imperative_expr()?
        } else {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "in or from".to_string() },
                span: self.current_span(),
            });
        };

        // Expect colon
        if !self.check(&TokenType::Colon) {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: ":".to_string() },
                span: self.current_span(),
            });
        }
        self.advance();

        // Expect indent
        if !self.check(&TokenType::Indent) {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedStatement,
                span: self.current_span(),
            });
        }
        self.advance();

        // Parse body statements
        let mut body_stmts = Vec::new();
        while !self.check(&TokenType::Dedent) && !self.is_at_end() {
            let stmt = self.parse_statement()?;
            body_stmts.push(stmt);
            if self.check(&TokenType::Period) {
                self.advance();
            }
        }

        if self.check(&TokenType::Dedent) {
            self.advance();
        }

        let body = self.ctx.stmts.expect("imperative arenas not initialized")
            .alloc_slice(body_stmts.into_iter());

        Ok(Stmt::Repeat { pattern, iterable, body })
    }

    fn parse_call_statement(&mut self) -> ParseResult<Stmt<'a>> {
        self.advance(); // consume "Call"

        // Parse function name (identifier)
        // Function names can be nouns, adjectives, or verbs (e.g., "work", "process")
        // Use the token's lexeme to match function definition casing
        let function = match &self.peek().kind {
            TokenType::Noun(sym) | TokenType::Adjective(sym) => {
                let s = *sym;
                self.advance();
                s
            }
            TokenType::Verb { .. } | TokenType::Ambiguous { .. } => {
                // Use lexeme (actual text) not lemma to preserve casing
                let s = self.peek().lexeme;
                self.advance();
                s
            }
            _ => {
                return Err(ParseError {
                    kind: ParseErrorKind::ExpectedIdentifier,
                    span: self.current_span(),
                });
            }
        };

        // Expect "with" followed by arguments
        let args = if self.check_preposition_is("with") {
            self.advance(); // consume "with"
            self.parse_call_arguments()?
        } else {
            Vec::new()
        };

        Ok(Stmt::Call { function, args })
    }

    fn parse_call_arguments(&mut self) -> ParseResult<Vec<&'a Expr<'a>>> {
        let mut args = Vec::new();

        // Parse first argument (may have Give keyword)
        let arg = self.parse_call_arg()?;
        args.push(arg);

        // Parse additional arguments separated by "and" or ","
        while self.check(&TokenType::And) || self.check(&TokenType::Comma) {
            self.advance(); // consume "and" or ","
            // A trailing comma (`f(1, 2,)`) ends the argument list.
            if self.check(&TokenType::RParen) {
                break;
            }
            let arg = self.parse_call_arg()?;
            args.push(arg);
        }

        Ok(args)
    }

    fn parse_call_arg(&mut self) -> ParseResult<&'a Expr<'a>> {
        // Check for Give keyword to mark ownership transfer
        if self.check(&TokenType::Give) {
            self.advance(); // consume "Give"
            let value = self.parse_comparison()?;
            return Ok(self.ctx.alloc_imperative_expr(Expr::Give { value }));
        }

        // Otherwise parse normal expression — use parse_comparison() so that
        // "and" remains available as an argument separator in parse_call_arguments()
        self.parse_comparison()
    }

    fn parse_condition(&mut self) -> ParseResult<&'a Expr<'a>> {
        // Grand Challenge: Parse compound conditions with "and" and "or"
        // "or" has lower precedence than "and"
        let expr = self.parse_or_condition()?;
        // Postfix unit conversion: `<expr> in <unit>` → `convert(expr, "unit")`, e.g.
        // `2 inches + 5 centimeters in feet`. The lowest-precedence postfix, so `in` applies to the
        // whole expression. Gated on the token after `in` being a UNIT word, so `for each x in list`
        // (loop var via expect_identifier; collection is not a unit) and `chunk at i in zone` are
        // untouched — neither places a unit word right after `in`.
        if self.check(&TokenType::In) || self.check_preposition_is("in") {
            // Zoned time: `<moment> in "America/New_York"` → the local time in that zone. The token
            // after `in` is a STRING (a zone name), which distinguishes it from `in <unit>` below.
            let zone_sym = match self.tokens.get(self.current + 1).map(|t| &t.kind) {
                Some(TokenType::StringLiteral(s)) => Some(*s),
                _ => None,
            };
            if let Some(zone_sym) = zone_sym {
                self.advance(); // "in"
                self.advance(); // the zone string
                let zone = self.ctx.alloc_imperative_expr(Expr::Literal(crate::ast::Literal::Text(zone_sym)));
                let func = self.interner.intern("in_zone");
                return Ok(self
                    .ctx
                    .alloc_imperative_expr(Expr::Call { function: func, args: vec![expr, zone] }));
            }
            let unit_lexeme = self.tokens.get(self.current + 1).and_then(|t| {
                if matches!(t.kind, TokenType::Identifier | TokenType::Noun(_) | TokenType::Adjective(_)) {
                    Some(t.lexeme)
                } else {
                    None
                }
            });
            if let Some(unit_lexeme) = unit_lexeme {
                if logicaffeine_base::quantity::units::by_name(self.interner.resolve(unit_lexeme)).is_some() {
                    self.advance(); // consume "in"
                    self.advance(); // consume the unit word
                    let unit_expr = self
                        .ctx
                        .alloc_imperative_expr(crate::ast::Expr::Literal(crate::ast::Literal::Text(unit_lexeme)));
                    let func = self.interner.intern("convert");
                    return Ok(self
                        .ctx
                        .alloc_imperative_expr(crate::ast::Expr::Call { function: func, args: vec![expr, unit_expr] }));
                }
            }
            // Currency conversion: `<money> in EUR` → `to_currency(money, "EUR")` via the ambient
            // rate context. Checked AFTER units (a unit word never reads as a currency); gated on a
            // real ISO-4217 code, so `for each x in list` and friends are untouched.
            let code_lexeme = self.tokens.get(self.current + 1).and_then(|t| {
                if matches!(
                    t.kind,
                    TokenType::Identifier | TokenType::Noun(_) | TokenType::ProperName(_) | TokenType::Adjective(_)
                ) {
                    Some(t.lexeme)
                } else {
                    None
                }
            });
            if let Some(code_lexeme) = code_lexeme {
                if logicaffeine_base::money::currency::by_code(self.interner.resolve(code_lexeme)).is_some() {
                    self.advance(); // consume "in"
                    self.advance(); // consume the currency code
                    let code_expr = self
                        .ctx
                        .alloc_imperative_expr(crate::ast::Expr::Literal(crate::ast::Literal::Text(code_lexeme)));
                    let func = self.interner.intern("to_currency");
                    return Ok(self
                        .ctx
                        .alloc_imperative_expr(crate::ast::Expr::Call { function: func, args: vec![expr, code_expr] }));
                }
            }
        }
        Ok(expr)
    }

    /// Parse "or" conditions (lower precedence than "and")
    fn parse_or_condition(&mut self) -> ParseResult<&'a Expr<'a>> {
        let mut left = self.parse_and_condition()?;

        while self.check(&TokenType::Or) || self.check_word("or") {
            self.advance();
            let right = self.parse_and_condition()?;
            left = self.ctx.alloc_imperative_expr(Expr::BinaryOp {
                op: BinaryOpKind::Or,
                left,
                right,
            });
        }

        Ok(left)
    }

    /// Parse "and" conditions (higher precedence than "or")
    fn parse_and_condition(&mut self) -> ParseResult<&'a Expr<'a>> {
        let mut left = self.parse_comparison()?;

        while self.check(&TokenType::And) || self.check_word("and") {
            self.advance();
            let right = self.parse_comparison()?;
            left = self.ctx.alloc_imperative_expr(Expr::BinaryOp {
                op: BinaryOpKind::And,
                left,
                right,
            });
        }

        Ok(left)
    }

    /// Whether the `in` at the current position introduces a postfix unit / currency / zone
    /// CONVERSION (handled by [`parse_condition`]) rather than Pythonic membership. Mirrors
    /// `parse_condition`'s exact gating: a zone STRING, or a unit / ISO-4217 currency word, right
    /// after `in`. Keeps `x in xs` membership working while restoring `<expr> in <unit|currency>`.
    fn in_introduces_conversion(&self) -> bool {
        match self.tokens.get(self.current + 1) {
            Some(t) => match &t.kind {
                TokenType::StringLiteral(_) => true,
                TokenType::Identifier | TokenType::Noun(_) | TokenType::ProperName(_) | TokenType::Adjective(_) => {
                    // A declared variable shadows a unit/currency abbreviation (declarer-wins):
                    // `20 in s`, where `s` is a bound set, is membership — NOT "convert 20 to
                    // seconds" (`s` = the seconds unit). A real conversion (`… in feet`, `… in USD`)
                    // never names a bound variable, so those are unaffected.
                    if self.user_bound.contains(&t.lexeme) {
                        return false;
                    }
                    let name = self.interner.resolve(t.lexeme);
                    logicaffeine_base::quantity::units::by_name(name).is_some()
                        || logicaffeine_base::money::currency::by_code(name).is_some()
                }
                _ => false,
            },
            None => false,
        }
    }

    /// Grand Challenge: Parse a single comparison expression
    fn parse_comparison(&mut self) -> ParseResult<&'a Expr<'a>> {
        // Handle unary "not" operator: "not x" or "not (expr)"
        if self.check(&TokenType::Not) || self.check_word("not") {
            self.advance(); // consume "not"
            let operand = self.parse_comparison()?; // recursive for "not not x"
            return Ok(self.ctx.alloc_imperative_expr(Expr::Not { operand }));
        }

        let left = self.parse_xor_expr()?;

        // Key-first membership: `x in xs` → `xs contains x` (Pythonic); `x not in
        // xs` → its negation. Reuses `Expr::Contains` (operands reversed). The
        // `Repeat for x in xs` header consumes its own `in` before the iterable,
        // so it never reaches here.
        //
        // BUT decline when `in` introduces a POSTFIX CONVERSION — `<expr> in <unit|currency>` or
        // `<moment> in "<zone>"` — which `parse_condition` handles at a higher level and must see the
        // `in` for. Without this, `10.00 EUR in USD` parses as membership (`USD contains …`) and
        // fails with "Undefined variable: USD"; likewise `<moment> in "America/New_York"`.
        if self.check(&TokenType::In) && !self.in_introduces_conversion() {
            self.advance(); // consume "in"
            let collection = self.parse_xor_expr()?;
            return Ok(self.ctx.alloc_imperative_expr(Expr::Contains { collection, value: left }));
        }
        if (self.check(&TokenType::Not) || self.check_word("not"))
            && matches!(
                self.tokens.get(self.current + 1).map(|t| &t.kind),
                Some(TokenType::In)
            )
        {
            self.advance(); // consume "not"
            self.advance(); // consume "in"
            let collection = self.parse_xor_expr()?;
            let contains = self.ctx.alloc_imperative_expr(Expr::Contains { collection, value: left });
            return Ok(self.ctx.alloc_imperative_expr(Expr::Not { operand: contains }));
        }

        // Check for comparison operators
        let op = if self.check(&TokenType::Equals) {
            self.advance();
            Some(BinaryOpKind::Eq)
        } else if self.check(&TokenType::Identity) {
            // "is equal to" was tokenized as TokenType::Identity
            self.advance();
            Some(BinaryOpKind::Eq)
        } else if self.check_word("is") {
            // Peek ahead to determine which comparison
            let saved_pos = self.current;
            self.advance(); // consume "is"

            // Number predicates desugar to a complete modulo test (no right
            // operand to combine) — return the whole Bool expression directly:
            // `x is even` → `x % 2 == 0`, `x is odd` → `x % 2 == 1`,
            // `x is divisible by n` → `x % n == 0`.
            if self.check_word("even") || self.check_word("odd") {
                let is_odd = self.check_word("odd");
                self.advance(); // consume "even"/"odd"
                let two = self.ctx.alloc_imperative_expr(Expr::Literal(crate::ast::Literal::Number(2)));
                let rem = self.ctx.alloc_imperative_expr(Expr::BinaryOp {
                    op: BinaryOpKind::Modulo, left, right: two,
                });
                let want = self.ctx.alloc_imperative_expr(Expr::Literal(
                    crate::ast::Literal::Number(if is_odd { 1 } else { 0 }),
                ));
                return Ok(self.ctx.alloc_imperative_expr(Expr::BinaryOp {
                    op: BinaryOpKind::Eq, left: rem, right: want,
                }));
            }
            if self.check_word("divisible") {
                self.advance(); // consume "divisible"
                if self.check_word("by") || self.check_preposition_is("by") {
                    self.advance(); // consume "by"
                    let divisor = self.parse_xor_expr()?;
                    let rem = self.ctx.alloc_imperative_expr(Expr::BinaryOp {
                        op: BinaryOpKind::Modulo, left, right: divisor,
                    });
                    let zero = self.ctx.alloc_imperative_expr(Expr::Literal(crate::ast::Literal::Number(0)));
                    return Ok(self.ctx.alloc_imperative_expr(Expr::BinaryOp {
                        op: BinaryOpKind::Eq, left: rem, right: zero,
                    }));
                }
                self.current = saved_pos;
                return Ok(left);
            }
            // `x is between lo and hi` → `lo <= x and x <= hi` (inclusive).
            if self.check_word("between") {
                self.advance(); // consume "between"
                let lo = self.parse_xor_expr()?;
                if self.check_word("and") || self.check(&TokenType::And) {
                    self.advance(); // consume "and"
                    let hi = self.parse_xor_expr()?;
                    let lower = self.ctx.alloc_imperative_expr(Expr::BinaryOp {
                        op: BinaryOpKind::LtEq, left: lo, right: left,
                    });
                    let upper = self.ctx.alloc_imperative_expr(Expr::BinaryOp {
                        op: BinaryOpKind::LtEq, left, right: hi,
                    });
                    return Ok(self.ctx.alloc_imperative_expr(Expr::BinaryOp {
                        op: BinaryOpKind::And, left: lower, right: upper,
                    }));
                }
                self.current = saved_pos;
                return Ok(left);
            }

            if self.check_word("greater") {
                self.advance(); // consume "greater"
                if self.check_word("than") || self.check_preposition_is("than") {
                    self.advance(); // consume "than"
                    Some(BinaryOpKind::Gt)
                } else {
                    self.current = saved_pos;
                    None
                }
            } else if self.check_word("less") {
                self.advance(); // consume "less"
                if self.check_word("than") || self.check_preposition_is("than") {
                    self.advance(); // consume "than"
                    Some(BinaryOpKind::Lt)
                } else {
                    self.current = saved_pos;
                    None
                }
            } else if self.check_word("at") {
                self.advance(); // consume "at"
                if self.check_word("least") {
                    self.advance(); // consume "least"
                    Some(BinaryOpKind::GtEq)
                } else if self.check_word("most") {
                    self.advance(); // consume "most"
                    Some(BinaryOpKind::LtEq)
                } else {
                    self.current = saved_pos;
                    None
                }
            } else if self.check_word("before") {
                // "is before X" → temporal `<` (a Moment/Date precedes another); generic `<`.
                self.advance(); // consume "before"
                Some(BinaryOpKind::Lt)
            } else if self.check_word("after") {
                // "is after X" → temporal `>` (a Moment/Date follows another); generic `>`.
                self.advance(); // consume "after"
                Some(BinaryOpKind::Gt)
            } else if self.check_word("not") || self.check(&TokenType::Not) {
                // "is not X" → NotEq
                self.advance(); // consume "not"
                Some(BinaryOpKind::NotEq)
            } else if self.check_word("equal") {
                // "is equal to X" → Eq
                self.advance(); // consume "equal"
                if self.check_preposition_is("to") {
                    self.advance(); // consume "to"
                    Some(BinaryOpKind::Eq)
                } else {
                    self.current = saved_pos;
                    None
                }
            } else if self.check_word("approximately") {
                // "is approximately X" → the tolerant float comparison
                // (`==` stays IEEE bit-exact). An optional "equal to" tail
                // also reads naturally: "is approximately equal to X".
                self.advance(); // consume "approximately"
                if self.check_word("equal") {
                    self.advance(); // consume "equal"
                    if self.check_preposition_is("to") {
                        self.advance(); // consume "to"
                    }
                }
                Some(BinaryOpKind::ApproxEq)
            } else if matches!(self.peek().kind, TokenType::Number(_))
                || (self.check(&TokenType::Minus)
                    && self.tokens.get(self.current + 1)
                        .is_some_and(|t| matches!(t.kind, TokenType::Number(_))))
            {
                // Bare `x is <number>` is equality (`x is equal to <number>` → `x == <number>`).
                // Guarded to a NUMBER literal (including a negated one), so `is a`/`is an`/`is the`/
                // `is nothing`/`is <predicate>` and every worded `is …` comparison above stay
                // untouched — nothing but a numeral reaches here. The numeral is left for the
                // right-operand parse below.
                Some(BinaryOpKind::Eq)
            } else {
                self.current = saved_pos;
                None
            }
        } else if self.check(&TokenType::Lt) {
            self.advance();
            Some(BinaryOpKind::Lt)
        } else if self.check(&TokenType::Gt) {
            self.advance();
            Some(BinaryOpKind::Gt)
        } else if self.check(&TokenType::LtEq) {
            self.advance();
            Some(BinaryOpKind::LtEq)
        } else if self.check(&TokenType::GtEq) {
            self.advance();
            Some(BinaryOpKind::GtEq)
        } else if self.check(&TokenType::EqEq) || self.check(&TokenType::Assign) {
            self.advance();
            Some(BinaryOpKind::Eq)
        } else if self.check(&TokenType::NotEq) {
            self.advance();
            Some(BinaryOpKind::NotEq)
        } else {
            None
        };

        if let Some(op) = op {
            let right = self.parse_xor_expr()?;
            let first = self.ctx.alloc_imperative_expr(Expr::BinaryOp { op, left, right });
            // Chained comparison: `lo <= x <= hi` → `(lo <= x) and (x <= hi)`
            // (math / Python reading). Only the SYMBOLIC operators chain; the
            // worded forms don't. `right` is the shared middle operand.
            if let Some(op2) = self.try_symbolic_comparison_op() {
                let hi = self.parse_xor_expr()?;
                let second = self.ctx.alloc_imperative_expr(Expr::BinaryOp {
                    op: op2, left: right, right: hi,
                });
                return Ok(self.ctx.alloc_imperative_expr(Expr::BinaryOp {
                    op: BinaryOpKind::And, left: first, right: second,
                }));
            }
            Ok(first)
        } else {
            Ok(left)
        }
    }

    /// Consume a SYMBOLIC comparison operator (`< <= > >= == !=`) if one is
    /// next, for chained comparisons. Worded forms (`is greater than`) are not
    /// chained. Returns `None` (consuming nothing) otherwise.
    fn try_symbolic_comparison_op(&mut self) -> Option<BinaryOpKind> {
        let op = if self.check(&TokenType::LtEq) {
            BinaryOpKind::LtEq
        } else if self.check(&TokenType::GtEq) {
            BinaryOpKind::GtEq
        } else if self.check(&TokenType::Lt) {
            BinaryOpKind::Lt
        } else if self.check(&TokenType::Gt) {
            BinaryOpKind::Gt
        } else if self.check(&TokenType::EqEq) {
            BinaryOpKind::Eq
        } else if self.check(&TokenType::NotEq) {
            BinaryOpKind::NotEq
        } else {
            return None;
        };
        self.advance();
        Some(op)
    }

    fn parse_let_statement(&mut self) -> ParseResult<Stmt<'a>> {
        self.advance(); // consume "Let"

        // Check for "mutable" keyword
        let mutable = if self.check_mutable_keyword() {
            self.advance();
            true
        } else {
            false
        };

        // Get identifier
        let var = self.expect_identifier()?;

        // Check for optional type annotation: `: Type`
        let ty = if self.check(&TokenType::Colon) {
            self.advance(); // consume ":"
            let type_expr = self.parse_type_expression()?;
            Some(self.ctx.alloc_type_expr(type_expr))
        } else {
            None
        };

        // Expect "be" or "="
        if !self.check(&TokenType::Be) && !self.check(&TokenType::Assign) {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "be or =".to_string() },
                span: self.current_span(),
            });
        }
        self.advance(); // consume "be" or "="

        // Phase 53: Check for "mounted at [path]" pattern (for Persistent types)
        if self.check_word("mounted") {
            self.advance(); // consume "mounted"
            if !self.check(&TokenType::At) && !self.check_preposition_is("at") {
                return Err(ParseError {
                    kind: ParseErrorKind::ExpectedKeyword { keyword: "at".to_string() },
                    span: self.current_span(),
                });
            }
            self.advance(); // consume "at"
            let path = self.parse_imperative_expr()?;
            return Ok(Stmt::Mount { var, path });
        }

        // Phase 51: Check for "a PeerAgent at [addr]" pattern
        if self.check_article() {
            let saved_pos = self.current;
            self.advance(); // consume article

            // Check if next word is "PeerAgent" (case insensitive)
            if let TokenType::Noun(sym) | TokenType::ProperName(sym) = self.peek().kind {
                let word = self.interner.resolve(sym).to_lowercase();
                if word == "peeragent" {
                    self.advance(); // consume "PeerAgent"

                    // Check for "at" keyword
                    if self.check(&TokenType::At) || self.check_preposition_is("at") {
                        self.advance(); // consume "at"

                        // Parse address expression
                        let address = self.parse_imperative_expr()?;

                        return Ok(Stmt::LetPeerAgent { var, address });
                    }
                }
            }
            // Not a PeerAgent, backtrack
            self.current = saved_pos;
        }

        // Phase 54: Check for "a [new] Pipe of Type" pattern. The optional `new`
        // matches the `a new X` idiom every other collection construction uses
        // (`a new Map`, `a new Set`); the guide writes `a new Pipe of Int`.
        if self.check_article() {
            let saved_pos = self.current;
            self.advance(); // consume article
            if self.check(&TokenType::New) {
                self.advance(); // consume optional "new"
            }

            if self.check(&TokenType::Pipe) {
                self.advance(); // consume "Pipe"

                // Expect "of"
                if !self.check_word("of") {
                    return Err(ParseError {
                        kind: ParseErrorKind::ExpectedKeyword { keyword: "of".to_string() },
                        span: self.current_span(),
                    });
                }
                self.advance(); // consume "of"

                // Parse element type
                let element_type = self.expect_identifier()?;

                // Variable registration now handled by DRS

                return Ok(Stmt::CreatePipe { var, element_type, capacity: None });
            }
            // Not a Pipe, backtrack
            self.current = saved_pos;
        }

        // Phase 54: Check for "Launch a task to..." pattern (for task handles)
        if self.check(&TokenType::Launch) {
            self.advance(); // consume "Launch"

            // Expect "a"
            if !self.check_article() {
                return Err(ParseError {
                    kind: ParseErrorKind::ExpectedKeyword { keyword: "a".to_string() },
                    span: self.current_span(),
                });
            }
            self.advance();

            // Expect "task"
            if !self.check(&TokenType::Task) {
                return Err(ParseError {
                    kind: ParseErrorKind::ExpectedKeyword { keyword: "task".to_string() },
                    span: self.current_span(),
                });
            }
            self.advance();

            // Expect "to"
            if !self.check(&TokenType::To) && !self.check_word("to") {
                return Err(ParseError {
                    kind: ParseErrorKind::ExpectedKeyword { keyword: "to".to_string() },
                    span: self.current_span(),
                });
            }
            self.advance();

            // Parse function name
            let function = self.expect_identifier()?;

            // Parse optional arguments: "with arg1, arg2"
            let args = if self.check_word("with") {
                self.advance();
                self.parse_call_arguments()?
            } else {
                vec![]
            };

            return Ok(Stmt::LaunchTaskWithHandle { handle: var, function, args });
        }

        // Parse expression value (simple: just a number for now)
        let value = self.parse_imperative_expr()?;

        // Phase 43B: Type check - verify declared type matches value type
        if let Some(declared_ty) = &ty {
            if let Some(inferred) = self.infer_literal_type(value) {
                if !self.check_type_compatibility(declared_ty, inferred) {
                    let expected = match declared_ty {
                        TypeExpr::Primitive(sym) | TypeExpr::Named(sym) => {
                            self.interner.resolve(*sym).to_string()
                        }
                        _ => "unknown".to_string(),
                    };
                    return Err(ParseError {
                        kind: ParseErrorKind::TypeMismatch {
                            expected,
                            found: inferred.to_string(),
                        },
                        span: self.current_span(),
                    });
                }
            }
        }

        // Check for optional "with capacity <expr>" — wraps value in Expr::WithCapacity
        let value = if self.check_word("with") {
            let saved = self.current;
            self.advance(); // consume "with"
            if self.check_word("capacity") {
                self.advance(); // consume "capacity"
                let cap_expr = self.parse_imperative_expr()?;
                self.ctx.alloc_imperative_expr(Expr::WithCapacity { value, capacity: cap_expr })
            } else {
                self.current = saved; // backtrack — "with" belongs to something else
                value
            }
        } else {
            value
        };

        // Register variable in WorldState's DRS with Owned state for ownership tracking
        self.world_state.drs.introduce_referent(var, var, crate::drs::Gender::Unknown, crate::drs::Number::Singular);

        self.user_bound.insert(var);
        Ok(Stmt::Let { var, ty, value, mutable })
    }

    fn check_mutable_keyword(&self) -> bool {
        // Check for TokenType::Mut (Phase 23b keyword)
        if matches!(self.peek().kind, TokenType::Mut) {
            return true;
        }
        // Check for "mutable" or "mut" as Noun/Adjective (backward compatibility)
        if let TokenType::Noun(sym) | TokenType::Adjective(sym) = self.peek().kind {
            let word = self.interner.resolve(sym).to_lowercase();
            word == "mutable" || word == "mut"
        } else {
            false
        }
    }

    /// Phase 43B: Infer the type of a literal expression
    fn infer_literal_type(&self, expr: &Expr<'_>) -> Option<&'static str> {
        match expr {
            Expr::Literal(lit) => match lit {
                crate::ast::Literal::Number(_) => Some("Int"),
                crate::ast::Literal::Float(_) => Some("Real"),
                crate::ast::Literal::Text(_) => Some("Text"),
                crate::ast::Literal::Boolean(_) => Some("Bool"),
                crate::ast::Literal::Nothing => Some("Unit"),
                crate::ast::Literal::Char(_) => Some("Char"),
                crate::ast::Literal::Duration(_) => Some("Duration"),
                crate::ast::Literal::Date(_) => Some("Date"),
                crate::ast::Literal::Moment(_) => Some("Moment"),
                crate::ast::Literal::Span { .. } => Some("Span"),
                crate::ast::Literal::Time(_) => Some("Time"),
            },
            _ => None, // Can't infer type for non-literals yet
        }
    }

    /// Phase 43B: Check if declared type matches inferred type
    fn check_type_compatibility(&self, declared: &TypeExpr<'_>, inferred: &str) -> bool {
        match declared {
            TypeExpr::Primitive(sym) | TypeExpr::Named(sym) => {
                let declared_name = self.interner.resolve(*sym);
                // Nat and Byte are compatible with Int literals; an integer literal is
                // also a valid Rational (`Let x: Rational be 5` → exact 5/1).
                declared_name.eq_ignore_ascii_case(inferred)
                    || (declared_name.eq_ignore_ascii_case("Nat") && inferred == "Int")
                    || (declared_name.eq_ignore_ascii_case("Byte") && inferred == "Int")
                    || (declared_name.eq_ignore_ascii_case("Rational") && inferred == "Int")
            }
            _ => true, // For generics/functions, skip check for now
        }
    }

    // =========================================================================
    // Phase 23b: Equals-style Assignment (x = 5)
    // =========================================================================

    /// Check if current token starts an equals-style assignment.
    /// Patterns: `identifier = value` or `identifier: Type = value`
    /// True when the statement is a compound assignment — it starts with an
    /// l-value root (identifier-like) and has a `+= -= *= /= %=` token before
    /// the statement terminator. The compound ops appear nowhere else, so their
    /// presence is unambiguous.
    fn peek_compound_assignment(&self) -> bool {
        let is_identifier = matches!(
            self.peek().kind,
            TokenType::Noun(_) | TokenType::ProperName(_) | TokenType::Identifier
                | TokenType::Adjective(_) | TokenType::Verb { .. }
                | TokenType::Particle(_) | TokenType::Ambiguous { .. }
                | TokenType::Pronoun { .. }
        );
        if !is_identifier {
            return false;
        }
        let mut offset = 1;
        while self.current + offset < self.tokens.len() {
            match &self.tokens[self.current + offset].kind {
                TokenType::PlusEq
                | TokenType::MinusEq
                | TokenType::StarEq
                | TokenType::SlashEq
                | TokenType::PercentEq => return true,
                TokenType::Period | TokenType::Newline | TokenType::EOF => return false,
                _ => offset += 1,
            }
        }
        false
    }

    /// Parse `<lvalue> <op>= <expr>` → `Set <lvalue> to <lvalue> <op> <expr>`.
    /// The l-value (identifier / `p.field` / `xs[i]`) is parsed as an
    /// expression — it stops cleanly at the compound-op token.
    fn parse_compound_assignment(&mut self) -> ParseResult<Stmt<'a>> {
        use crate::ast::Expr;
        let target = self.parse_imperative_expr()?;
        let op = match self.peek().kind {
            TokenType::PlusEq => BinaryOpKind::Add,
            TokenType::MinusEq => BinaryOpKind::Subtract,
            TokenType::StarEq => BinaryOpKind::Multiply,
            TokenType::SlashEq => BinaryOpKind::Divide,
            TokenType::PercentEq => BinaryOpKind::Modulo,
            _ => {
                return Err(ParseError {
                    kind: ParseErrorKind::ExpectedKeyword { keyword: "+= -= *= /= %=".to_string() },
                    span: self.current_span(),
                });
            }
        };
        self.advance(); // consume the compound op
        let rhs = self.parse_imperative_expr()?;
        let combined = self.ctx.alloc_imperative_expr(Expr::BinaryOp { op, left: target, right: rhs });
        // Desugar by target shape (mirrors `Set`): identifier → Set (auto-mutable
        // via collect_mutable_vars), field → SetField, index → the place desugar.
        match target {
            Expr::Identifier(sym) => Ok(Stmt::Set { target: *sym, value: combined }),
            Expr::FieldAccess { object, field } => {
                Ok(Stmt::SetField { object, field: *field, value: combined })
            }
            Expr::Index { collection, index } => {
                Ok(self.desugar_place_set_index(collection, index, combined))
            }
            _ => Err(ParseError {
                kind: ParseErrorKind::ExpectedIdentifier,
                span: self.current_span(),
            }),
        }
    }

    fn peek_equals_assignment(&self) -> bool {
        // Must start with an identifier-like token
        // Note: Unknown words default to Adjective in the lexer
        // Verbs, Particles, and Ambiguous can also be variable names
        let is_identifier = matches!(
            self.peek().kind,
            TokenType::Noun(_) | TokenType::ProperName(_) | TokenType::Identifier
            | TokenType::Adjective(_) | TokenType::Verb { .. }
            | TokenType::Particle(_) | TokenType::Ambiguous { .. }
            | TokenType::Pronoun { .. }
        );
        if !is_identifier {
            return false;
        }

        // Check what follows the identifier
        if self.current + 1 >= self.tokens.len() {
            return false;
        }

        let next = &self.tokens[self.current + 1].kind;

        // Direct assignment: identifier = value
        if matches!(next, TokenType::Assign) {
            return true;
        }

        // Type-annotated assignment: identifier: Type = value
        // Check for colon, then scan for = before Period/Newline
        if matches!(next, TokenType::Colon) {
            let mut offset = 2;
            while self.current + offset < self.tokens.len() {
                let tok = &self.tokens[self.current + offset].kind;
                if matches!(tok, TokenType::Assign) {
                    return true;
                }
                if matches!(tok, TokenType::Period | TokenType::Newline | TokenType::EOF) {
                    return false;
                }
                offset += 1;
            }
        }

        false
    }

    /// Parse equals-style assignment: `x = 5` or `x: Int = 5` or `mut x = 5`
    fn parse_equals_assignment(&mut self, explicit_mutable: bool) -> ParseResult<Stmt<'a>> {
        // If explicit_mutable is true, we've already checked for Mut token
        if explicit_mutable {
            self.advance(); // consume "mut"
        }

        // Get variable name
        let var = self.expect_identifier()?;

        // Check for optional type annotation: `: Type`
        let ty = if self.check(&TokenType::Colon) {
            self.advance(); // consume ":"
            let type_expr = self.parse_type_expression()?;
            Some(self.ctx.alloc_type_expr(type_expr))
        } else {
            None
        };

        // Expect '='
        if !self.check(&TokenType::Assign) {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "=".to_string() },
                span: self.current_span(),
            });
        }
        self.advance(); // consume '='

        // Parse value expression
        let value = self.parse_imperative_expr()?;

        // Check for optional "with capacity <expr>" — wraps value in Expr::WithCapacity
        let value = if self.check_word("with") {
            let saved = self.current;
            self.advance(); // consume "with"
            if self.check_word("capacity") {
                self.advance(); // consume "capacity"
                let cap_expr = self.parse_imperative_expr()?;
                self.ctx.alloc_imperative_expr(Expr::WithCapacity { value, capacity: cap_expr })
            } else {
                self.current = saved; // backtrack
                value
            }
        } else {
            value
        };

        // `x = e` on an EXISTING binding MUTATES it (no silent shadow — the
        // loop-body `total = total + i` footgun updated a fresh ghost while
        // the outer variable never moved). A `mut`/type-annotated form or a
        // fresh name is a new binding. The mutation auto-marks the target
        // mutable downstream (codegen derives `let mut` from the `Set`).
        if !explicit_mutable && ty.is_none() && self.user_bound.contains(&var) {
            return Ok(Stmt::Set { target: var, value });
        }

        // Register variable in WorldState's DRS
        self.world_state.drs.introduce_referent(var, var, crate::drs::Gender::Unknown, crate::drs::Number::Singular);

        self.user_bound.insert(var);
        Ok(Stmt::Let { var, ty, value, mutable: explicit_mutable })
    }

    fn parse_set_statement(&mut self) -> ParseResult<Stmt<'a>> {
        use crate::ast::Expr;
        self.advance(); // consume "Set"

        // Parse target - can be identifier or field access expression
        let target_expr = self.parse_imperative_expr()?;

        // Support "Set X at KEY to VALUE" syntax for map insertion
        let target_expr = if self.check(&TokenType::At) {
            self.advance(); // consume "at"
            let key = self.parse_imperative_expr()?;
            self.ctx.alloc_imperative_expr(Expr::Index { collection: target_expr, index: key })
        } else {
            target_expr
        };

        // Expect "to" - can be TokenType::To or Preposition("to")
        let is_to = self.check(&TokenType::To) || matches!(
            &self.peek().kind,
            TokenType::Preposition(sym) if self.interner.resolve(*sym) == "to"
        );
        if !is_to {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "to".to_string() },
                span: self.current_span(),
            });
        }
        self.advance(); // consume "to"

        // Parse expression value
        let value = self.parse_imperative_expr()?;

        // Phase 31: Handle field access targets
        // Also handle index targets: Set item N of X to Y
        match target_expr {
            Expr::FieldAccess { object, field } => {
                Ok(Stmt::SetField { object: *object, field: *field, value })
            }
            Expr::Identifier(target) => {
                Ok(Stmt::Set { target: *target, value })
            }
            Expr::Index { collection, index } => {
                Ok(self.desugar_place_set_index(*collection, *index, value))
            }
            _ => Err(ParseError {
                kind: ParseErrorKind::ExpectedIdentifier,
                span: self.current_span(),
            })
        }
    }

    fn parse_return_statement(&mut self) -> ParseResult<Stmt<'a>> {
        self.advance(); // consume "Return"

        // Check if there's a value or just "Return."
        if self.check(&TokenType::Period) || self.is_at_end() {
            return Ok(Stmt::Return { value: None });
        }

        // Use parse_condition (the full value grammar: and/or, comparisons, AND the `in <unit>` /
        // `in "<zone>"` postfix) so a Return is as expressive as a Show/Let — `Return q in feet`,
        // `Return m in "America/New_York"`, `Return a is before b`.
        let value = self.parse_condition()?;
        // Trailing-condition guard: `Return X if c.` → `If c: Return X.`
        if self.check(&TokenType::If) {
            self.advance(); // consume "if"
            let cond = self.parse_condition()?;
            let ret = Stmt::Return { value: Some(value) };
            let then_block = self.ctx.stmts.expect("imperative arenas not initialized")
                .alloc_slice(std::iter::once(ret));
            return Ok(Stmt::If { cond, then_block, else_block: None });
        }
        Ok(Stmt::Return { value: Some(value) })
    }

    fn parse_break_statement(&mut self) -> ParseResult<Stmt<'a>> {
        self.advance(); // consume "Break"
        Ok(Stmt::Break)
    }

    fn parse_assert_statement(&mut self) -> ParseResult<Stmt<'a>> {
        self.advance(); // consume "Assert"

        // Optionally consume "that" (may be tokenized as That or Article(Distal))
        if self.check(&TokenType::That) || matches!(self.peek().kind, TokenType::Article(Definiteness::Distal)) {
            self.advance();
        }

        // Parse condition using imperative expression parser
        // This allows syntax like "Assert that b is not 0."
        let condition = self.parse_condition()?;

        Ok(Stmt::RuntimeAssert { condition, hard: false })
    }

    /// `Require that <cond>.` — an ENFORCED runtime invariant lowering to a hard
    /// `assert!` (survives release). Same surface as `Assert that` but `hard: true`;
    /// this is the form a proven property check (`Require that check_thm(args).`) uses.
    fn parse_require_statement(&mut self) -> ParseResult<Stmt<'a>> {
        self.advance(); // consume "Require"

        // Optionally consume "that" (may be tokenized as That or Article(Distal)).
        if self.check(&TokenType::That) || matches!(self.peek().kind, TokenType::Article(Definiteness::Distal)) {
            self.advance();
        }

        let condition = self.parse_condition()?;
        Ok(Stmt::RuntimeAssert { condition, hard: true })
    }

    /// Phase 35: Parse Trust statement
    /// Syntax: Trust [that] [proposition] because [justification].
    fn parse_trust_statement(&mut self) -> ParseResult<Stmt<'a>> {
        self.advance(); // consume "Trust"

        // Optionally consume "that" (may be tokenized as That or Article(Distal))
        if self.check(&TokenType::That) || matches!(self.peek().kind, TokenType::Article(Definiteness::Distal)) {
            self.advance();
        }

        // Save current mode and switch to declarative for proposition parsing
        let saved_mode = self.mode;
        self.mode = ParserMode::Declarative;

        // Parse the proposition using the Logic Kernel. The proposition is a
        // PREFIX of the statement — it ends where the host keyword "because"
        // begins, which is checked just below.
        let proposition = self.parse_prefix()?;

        // Restore mode
        self.mode = saved_mode;

        // Expect "because"
        if !self.check(&TokenType::Because) {
            return Err(ParseError {
                kind: ParseErrorKind::UnexpectedToken {
                    expected: TokenType::Because,
                    found: self.peek().kind.clone(),
                },
                span: self.current_span(),
            });
        }
        self.advance(); // consume "because"

        // Parse justification (string literal)
        let justification = match &self.peek().kind {
            TokenType::StringLiteral(sym) => {
                let s = *sym;
                self.advance();
                s
            }
            _ => {
                return Err(ParseError {
                    kind: ParseErrorKind::UnexpectedToken {
                        expected: TokenType::StringLiteral(self.interner.intern("")),
                        found: self.peek().kind.clone(),
                    },
                    span: self.current_span(),
                });
            }
        };

        Ok(Stmt::Trust { proposition, justification })
    }

    /// Phase 50: Parse Check statement - mandatory security guard
    /// Syntax: Check that [subject] is [predicate].
    /// Syntax: Check that [subject] can [action] the [object].
    fn parse_check_statement(&mut self) -> ParseResult<Stmt<'a>> {
        let start_span = self.current_span();
        self.advance(); // consume "Check"

        // Optionally consume "that"
        if self.check(&TokenType::That) {
            self.advance();
        }

        // Consume optional "the"
        if matches!(self.peek().kind, TokenType::Article(_)) {
            self.advance();
        }

        // Parse subject identifier (e.g., "user")
        let subject = match &self.peek().kind {
            TokenType::Noun(sym) | TokenType::Adjective(sym) | TokenType::ProperName(sym) => {
                let s = *sym;
                self.advance();
                s
            }
            _ => {
                // Try to get an identifier
                let tok = self.peek();
                let s = tok.lexeme;
                self.advance();
                s
            }
        };

        // Determine if this is a predicate check ("is admin") or capability check ("can publish")
        let is_capability;
        let predicate;
        let object;

        if self.check(&TokenType::Is) || self.check(&TokenType::Are) {
            // Predicate check: "user is admin"
            is_capability = false;
            self.advance(); // consume "is" / "are"

            // Parse predicate name (e.g., "admin")
            predicate = match &self.peek().kind {
                TokenType::Noun(sym) | TokenType::Adjective(sym) | TokenType::ProperName(sym) => {
                    let s = *sym;
                    self.advance();
                    s
                }
                _ => {
                    let tok = self.peek();
                    let s = tok.lexeme;
                    self.advance();
                    s
                }
            };
            object = None;
        } else if self.check(&TokenType::Can) {
            // Capability check: "user can publish the document"
            is_capability = true;
            self.advance(); // consume "can"

            // Parse action (e.g., "publish", "edit", "delete")
            predicate = match &self.peek().kind {
                TokenType::Verb { lemma, .. } => {
                    let s = *lemma;
                    self.advance();
                    s
                }
                TokenType::Noun(sym) | TokenType::Adjective(sym) | TokenType::ProperName(sym) => {
                    let s = *sym;
                    self.advance();
                    s
                }
                _ => {
                    let tok = self.peek();
                    let s = tok.lexeme;
                    self.advance();
                    s
                }
            };

            // Consume optional "the"
            if matches!(self.peek().kind, TokenType::Article(_)) {
                self.advance();
            }

            // Parse object (e.g., "document")
            let obj = match &self.peek().kind {
                TokenType::Noun(sym) | TokenType::Adjective(sym) | TokenType::ProperName(sym) => {
                    let s = *sym;
                    self.advance();
                    s
                }
                _ => {
                    let tok = self.peek();
                    let s = tok.lexeme;
                    self.advance();
                    s
                }
            };
            object = Some(obj);
        } else {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "is/can".to_string() },
                span: self.current_span(),
            });
        }

        // Build source text for error message
        let source_text = if is_capability {
            let obj_name = self.interner.resolve(object.unwrap());
            let pred_name = self.interner.resolve(predicate);
            let subj_name = self.interner.resolve(subject);
            format!("{} can {} the {}", subj_name, pred_name, obj_name)
        } else {
            let pred_name = self.interner.resolve(predicate);
            let subj_name = self.interner.resolve(subject);
            format!("{} is {}", subj_name, pred_name)
        };

        Ok(Stmt::Check {
            subject,
            predicate,
            is_capability,
            object,
            source_text,
            span: start_span,
        })
    }

    /// Read the current token's lexeme as an owned `String` and advance.
    fn read_word_string(&mut self) -> String {
        let s = self.interner.resolve(self.peek().lexeme).to_string();
        self.advance();
        s
    }

    /// Expect a specific keyword (case-insensitive) and advance; else a `Custom` error.
    fn expect_keyword(&mut self, word: &str) -> ParseResult<()> {
        if self.check_word(word) {
            self.advance();
            Ok(())
        } else {
            Err(ParseError {
                kind: ParseErrorKind::Custom(format!("expected `{}` here", word)),
                span: self.current_span(),
            })
        }
    }

    /// Read an integer literal token and advance; else a `Custom` error.
    fn read_int_literal(&mut self) -> ParseResult<i64> {
        if let TokenType::Number(sym) = &self.peek().kind {
            let sym = *sym;
            self.advance();
            self.interner.resolve(sym).parse::<i64>().map_err(|_| ParseError {
                kind: ParseErrorKind::Custom("expected an integer bound".to_string()),
                span: self.current_span(),
            })
        } else {
            Err(ParseError {
                kind: ParseErrorKind::Custom("expected an integer bound".to_string()),
                span: self.current_span(),
            })
        }
    }

    /// `Accept computed <Name> where <param> is an Int from <lo> to <hi>` — a parse-time
    /// acceptance-contract declaration. Records the named integer bounds (consumed by a later
    /// `Run … under <Name>`) and emits NO runtime statement.
    fn parse_accept_contract(&mut self) -> ParseResult<()> {
        self.advance(); // "Accept"
        self.expect_keyword("computed")?;
        let name = self.read_word_string();
        self.expect_keyword("where")?;
        let _param = self.read_word_string(); // the parameter name is documentation only
        self.expect_keyword("is")?;
        if self.check_word("a") || self.check_word("an") {
            self.advance();
        }
        self.expect_keyword("Int")?;
        self.expect_keyword("from")?;
        let lo = self.read_int_literal()?;
        // "to" can be the `To` token or the bare word.
        if self.check(&TokenType::To) || self.check_word("to") {
            self.advance();
        } else {
            return Err(ParseError {
                kind: ParseErrorKind::Custom("expected `to` between the contract bounds".to_string()),
                span: self.current_span(),
            });
        }
        let hi = self.read_int_literal()?;
        if self.check(&TokenType::Period) {
            self.advance(); // this declaration `continue`s in parse_program, so eat its own `.`
        }
        self.contracts.insert(name, (lo, hi));
        Ok(())
    }

    /// `Run <f> on <arg> under <Name> into <var>` → `Let <var> be run_accepted(<f>, <arg>, lo, hi)`,
    /// inlining the named acceptance contract's bounds. The trailing `.` is consumed by
    /// `parse_program` (this returns a real statement).
    fn parse_run_under_contract(&mut self) -> ParseResult<Stmt<'a>> {
        self.advance(); // "Run"
        let f_expr = self.parse_imperative_expr()?;
        self.expect_keyword("on")?;
        let arg_expr = self.parse_imperative_expr()?;
        self.expect_keyword("under")?;
        let name = self.read_word_string();
        let (lo, hi) = *self.contracts.get(&name).ok_or_else(|| ParseError {
            kind: ParseErrorKind::Custom(format!(
                "unknown acceptance contract `{name}` — declare it with `Accept computed {name} where …`"
            )),
            span: self.current_span(),
        })?;
        self.expect_keyword("into")?;
        let var = self.peek().lexeme;
        self.advance();
        let lo_e = self.ctx.alloc_imperative_expr(Expr::Literal(crate::ast::Literal::Number(lo)));
        let hi_e = self.ctx.alloc_imperative_expr(Expr::Literal(crate::ast::Literal::Number(hi)));
        let run_sym = self.interner.intern("run_accepted");
        let call = self
            .ctx
            .alloc_imperative_expr(Expr::Call { function: run_sym, args: vec![f_expr, arg_expr, lo_e, hi_e] });
        Ok(Stmt::Let { var, ty: None, value: call, mutable: false })
    }

    /// Phase 51: Parse Listen statement - bind to network address
    /// Syntax: Listen on [address].
    fn parse_listen_statement(&mut self) -> ParseResult<Stmt<'a>> {
        self.advance(); // consume "Listen"

        // Expect "on" preposition
        if !self.check_preposition_is("on") {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "on".to_string() },
                span: self.current_span(),
            });
        }
        self.advance(); // consume "on"

        // Parse address expression (string literal or variable)
        let address = self.parse_imperative_expr()?;

        let secure = self.parse_secure_clause()?;
        Ok(Stmt::Listen { address, secure })
    }

    /// Phase 51: Parse Connect statement - dial remote peer
    /// Syntax: Connect to [address].
    fn parse_connect_statement(&mut self) -> ParseResult<Stmt<'a>> {
        self.advance(); // consume "Connect"

        // Expect "to" (can be TokenType::To or preposition)
        if !self.check(&TokenType::To) && !self.check_preposition_is("to") {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "to".to_string() },
                span: self.current_span(),
            });
        }
        self.advance(); // consume "to"

        // Parse address expression
        let address = self.parse_imperative_expr()?;

        let secure = self.parse_secure_clause()?;
        Ok(Stmt::ConnectTo { address, secure })
    }

    /// Parse the optional PNP one-time-pad clause `with pad "<path>" as initiator|responder` that may
    /// trail a `Connect`/`Listen`. Returns `None` when the clause is absent (a bare statement), so the
    /// wire/behavior is byte-identical for programs that don't opt in.
    fn parse_secure_clause(&mut self) -> ParseResult<Option<crate::ast::SecurePad<'a>>> {
        // Only engage on the two-word lead `with pad`, so a stray `with` elsewhere is left alone.
        if !(self.check_word("with") && self.peek_word_at(1, "pad")) {
            return Ok(None);
        }
        self.advance(); // "with"
        self.advance(); // "pad"
        let pad = self.parse_imperative_expr()?;
        if !self.check_word("as") {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "as".to_string() },
                span: self.current_span(),
            });
        }
        self.advance(); // "as"
        let role = if self.check_word("initiator") {
            self.advance();
            crate::ast::SecureRole::Initiator
        } else if self.check_word("responder") {
            self.advance();
            crate::ast::SecureRole::Responder
        } else {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "initiator or responder".to_string() },
                span: self.current_span(),
            });
        };
        Ok(Some(crate::ast::SecurePad { pad, role }))
    }

    /// Phase 51: Parse Sleep statement - pause execution
    /// Syntax: Sleep [milliseconds].
    fn parse_sleep_statement(&mut self) -> ParseResult<Stmt<'a>> {
        self.advance(); // consume "Sleep"

        // Parse milliseconds expression (number or variable)
        let milliseconds = self.parse_imperative_expr()?;

        Ok(Stmt::Sleep { milliseconds })
    }

    /// Phase 52: Parse Sync statement - automatic CRDT replication
    /// Syntax: Sync [var] on [topic].
    fn parse_sync_statement(&mut self) -> ParseResult<Stmt<'a>> {
        self.advance(); // consume "Sync"

        // Parse variable name (must be an identifier)
        // Phase 49: Also handle Verb and Ambiguous tokens (e.g., "state" can be verb or noun)
        let var = match &self.tokens[self.current].kind {
            TokenType::ProperName(sym) | TokenType::Noun(sym) | TokenType::Adjective(sym) => {
                let s = *sym;
                self.advance();
                s
            }
            TokenType::Verb { .. } | TokenType::Ambiguous { .. } => {
                let s = self.tokens[self.current].lexeme;
                self.advance();
                s
            }
            _ => {
                return Err(ParseError {
                    kind: ParseErrorKind::ExpectedKeyword { keyword: "variable name".to_string() },
                    span: self.current_span(),
                });
            }
        };

        // Expect "on" preposition
        if !self.check_preposition_is("on") {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "on".to_string() },
                span: self.current_span(),
            });
        }
        self.advance(); // consume "on"

        // Parse topic expression (string literal or variable)
        let topic = self.parse_imperative_expr()?;

        Ok(Stmt::Sync { var, topic })
    }

    /// Phase 53: Parse Mount statement
    /// Syntax: Mount [var] at [path].
    /// Example: Mount counter at "data/counter.journal".
    fn parse_mount_statement(&mut self) -> ParseResult<Stmt<'a>> {
        self.advance(); // consume "Mount"

        // Parse variable name (must be an identifier)
        // Phase 49: Also handle Verb and Ambiguous tokens
        let var = match &self.tokens[self.current].kind {
            TokenType::ProperName(sym) | TokenType::Noun(sym) | TokenType::Adjective(sym) => {
                let s = *sym;
                self.advance();
                s
            }
            TokenType::Verb { .. } | TokenType::Ambiguous { .. } => {
                let s = self.tokens[self.current].lexeme;
                self.advance();
                s
            }
            _ => {
                return Err(ParseError {
                    kind: ParseErrorKind::ExpectedKeyword { keyword: "variable name".to_string() },
                    span: self.current_span(),
                });
            }
        };

        // Expect "at" keyword (TokenType::At in imperative mode)
        if !self.check(&TokenType::At) {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "at".to_string() },
                span: self.current_span(),
            });
        }
        self.advance(); // consume "at"

        // Parse path expression (string literal or variable)
        let path = self.parse_imperative_expr()?;

        Ok(Stmt::Mount { var, path })
    }

    // =========================================================================
    // Phase 54: Go-like Concurrency Parser Methods
    // =========================================================================

    /// Helper: Check if lookahead contains "into" (for Send...into pipe disambiguation)
    fn lookahead_contains_into(&self) -> bool {
        for i in self.current..std::cmp::min(self.current + 5, self.tokens.len()) {
            if matches!(self.tokens[i].kind, TokenType::Into) {
                return true;
            }
        }
        false
    }

    /// Helper: Check if lookahead is "the first of" (for Await select disambiguation)
    fn lookahead_is_first_of(&self) -> bool {
        // Check for "Await the first of:"
        self.current + 3 < self.tokens.len()
            && matches!(self.tokens.get(self.current + 1), Some(t) if matches!(t.kind, TokenType::Article(_)))
            && self.tokens.get(self.current + 2)
                .map(|t| self.interner.resolve(t.lexeme).to_lowercase() == "first")
                .unwrap_or(false)
    }

    /// Phase 54: Parse Launch statement - spawn a task
    /// Syntax: Launch a task to verb(args).
    fn parse_launch_statement(&mut self) -> ParseResult<Stmt<'a>> {
        self.advance(); // consume "Launch"

        // Expect "a"
        if !self.check_article() {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "a".to_string() },
                span: self.current_span(),
            });
        }
        self.advance();

        // Expect "task"
        if !self.check(&TokenType::Task) {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "task".to_string() },
                span: self.current_span(),
            });
        }
        self.advance();

        // Expect "to"
        if !self.check(&TokenType::To) && !self.check_preposition_is("to") {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "to".to_string() },
                span: self.current_span(),
            });
        }
        self.advance();

        // Parse function name
        // Phase 49: Also handle Verb and Ambiguous tokens (e.g., "greet" can be a verb)
        let function = match &self.tokens[self.current].kind {
            TokenType::ProperName(sym) | TokenType::Noun(sym) | TokenType::Adjective(sym) => {
                let s = *sym;
                self.advance();
                s
            }
            TokenType::Verb { .. } | TokenType::Ambiguous { .. } => {
                let s = self.tokens[self.current].lexeme;
                self.advance();
                s
            }
            _ => {
                return Err(ParseError {
                    kind: ParseErrorKind::ExpectedKeyword { keyword: "function name".to_string() },
                    span: self.current_span(),
                });
            }
        };

        // Optional arguments in parentheses or with "with" keyword
        let args = if self.check(&TokenType::LParen) {
            self.parse_call_arguments()?
        } else if self.check_word("with") {
            self.advance(); // consume "with"
            let mut args = Vec::new();
            let arg = self.parse_imperative_expr()?;
            args.push(arg);
            // Handle additional args separated by "and"
            while self.check(&TokenType::And) {
                self.advance();
                let arg = self.parse_imperative_expr()?;
                args.push(arg);
            }
            args
        } else {
            Vec::new()
        };

        Ok(Stmt::LaunchTask { function, args })
    }

    /// Phase 54: Parse Send into pipe statement
    /// Syntax: Send value into pipe.
    fn parse_send_pipe_statement(&mut self) -> ParseResult<Stmt<'a>> {
        self.advance(); // consume "Send"

        // Parse value expression
        let value = self.parse_imperative_expr()?;

        // Expect "into"
        if !self.check(&TokenType::Into) {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "into".to_string() },
                span: self.current_span(),
            });
        }
        self.advance();

        // Parse pipe expression
        let pipe = self.parse_imperative_expr()?;

        Ok(Stmt::SendPipe { value, pipe })
    }

    /// Phase 54: Parse Receive from pipe statement
    /// Syntax: Receive x from pipe.
    fn parse_receive_pipe_statement(&mut self) -> ParseResult<Stmt<'a>> {
        self.advance(); // consume "Receive"

        // Get variable name - use expect_identifier which handles various token types
        let var = self.expect_identifier()?;

        // Expect "from"
        if !self.check(&TokenType::From) && !self.check_preposition_is("from") {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "from".to_string() },
                span: self.current_span(),
            });
        }
        self.advance();

        // Parse pipe expression
        let pipe = self.parse_imperative_expr()?;

        Ok(Stmt::ReceivePipe { var, pipe })
    }

    /// Phase 54: Parse Try statement (non-blocking send/receive)
    /// Syntax: Try to send x into pipe. OR Try to receive x from pipe.
    fn parse_try_statement(&mut self) -> ParseResult<Stmt<'a>> {
        self.advance(); // consume "Try"

        // Expect "to"
        if !self.check(&TokenType::To) && !self.check_preposition_is("to") {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "to".to_string() },
                span: self.current_span(),
            });
        }
        self.advance();

        // Check if send or receive
        if self.check(&TokenType::Send) {
            self.advance(); // consume "Send"
            let value = self.parse_imperative_expr()?;

            if !self.check(&TokenType::Into) {
                return Err(ParseError {
                    kind: ParseErrorKind::ExpectedKeyword { keyword: "into".to_string() },
                    span: self.current_span(),
                });
            }
            self.advance();

            let pipe = self.parse_imperative_expr()?;
            Ok(Stmt::TrySendPipe { value, pipe, result: None })
        } else if self.check(&TokenType::Receive) {
            self.advance(); // consume "Receive"

            let var = self.expect_identifier()?;

            if !self.check(&TokenType::From) && !self.check_preposition_is("from") {
                return Err(ParseError {
                    kind: ParseErrorKind::ExpectedKeyword { keyword: "from".to_string() },
                    span: self.current_span(),
                });
            }
            self.advance();

            let pipe = self.parse_imperative_expr()?;
            Ok(Stmt::TryReceivePipe { var, pipe })
        } else {
            Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "send or receive".to_string() },
                span: self.current_span(),
            })
        }
    }

    /// Shared helper: consume `Escape to <Language>: Indent EscapeBlock Dedent`.
    /// Returns (language, code, span).
    fn parse_escape_body(&mut self) -> ParseResult<(crate::intern::Symbol, crate::intern::Symbol, crate::token::Span)> {
        let start_span = self.current_span();
        self.advance(); // consume "Escape"

        // Expect "to"
        if !self.check(&TokenType::To) && !self.check_preposition_is("to") {
            return Err(ParseError {
                kind: ParseErrorKind::Custom(
                    "Expected 'to' after 'Escape'. Syntax: Escape to Rust:".to_string()
                ),
                span: self.current_span(),
            });
        }
        self.advance(); // consume "to"

        // Parse language name — "Rust" will be tokenized as ProperName
        let language = match &self.peek().kind {
            TokenType::ProperName(sym) => {
                let s = *sym;
                self.advance();
                s
            }
            TokenType::Noun(sym) | TokenType::Adjective(sym) => {
                let s = *sym;
                self.advance();
                s
            }
            _ => {
                return Err(ParseError {
                    kind: ParseErrorKind::Custom(
                        "Expected language name after 'Escape to'. Currently only 'Rust' is supported.".to_string()
                    ),
                    span: self.current_span(),
                });
            }
        };

        // Validate: only "Rust" is supported for now
        if !language.is(self.interner, "Rust") {
            let lang_str = self.interner.resolve(language);
            return Err(ParseError {
                kind: ParseErrorKind::Custom(
                    format!("Unsupported escape target '{}'. Only 'Rust' is supported.", lang_str)
                ),
                span: self.current_span(),
            });
        }

        // Expect colon
        if !self.check(&TokenType::Colon) {
            return Err(ParseError {
                kind: ParseErrorKind::Custom(
                    "Expected ':' after 'Escape to Rust'. Syntax: Escape to Rust:".to_string()
                ),
                span: self.current_span(),
            });
        }
        self.advance(); // consume ":"

        // Expect Indent (the indented block follows)
        if !self.check(&TokenType::Indent) {
            return Err(ParseError {
                kind: ParseErrorKind::Custom(
                    "Expected indented block after 'Escape to Rust:'.".to_string()
                ),
                span: self.current_span(),
            });
        }
        self.advance(); // consume Indent

        // Expect the raw EscapeBlock token
        let code = match &self.peek().kind {
            TokenType::EscapeBlock(sym) => {
                let s = *sym;
                self.advance();
                s
            }
            _ => {
                return Err(ParseError {
                    kind: ParseErrorKind::Custom(
                        "Escape block body is empty or malformed.".to_string()
                    ),
                    span: self.current_span(),
                });
            }
        };

        // Expect Dedent (block ends)
        if self.check(&TokenType::Dedent) {
            self.advance();
        }

        let end_span = self.previous().span;
        Ok((language, code, crate::token::Span::new(start_span.start, end_span.end)))
    }

    /// Parse an escape hatch block: `Escape to Rust: <indented raw code>`
    fn parse_escape_statement(&mut self) -> ParseResult<Stmt<'a>> {
        let (language, code, span) = self.parse_escape_body()?;
        Ok(Stmt::Escape { language, code, span })
    }

    /// Parse an escape hatch expression: `Escape to Rust: <indented raw code>`
    /// Used in expression position: `Let x: Int be Escape to Rust:`
    fn parse_escape_expr(&mut self) -> ParseResult<&'a Expr<'a>> {
        let (language, code, _span) = self.parse_escape_body()?;
        Ok(self.ctx.alloc_imperative_expr(Expr::Escape { language, code }))
    }

    /// Parse a `## Requires` block into a list of `Stmt::Require` nodes.
    /// Loops until the next block header or EOF, parsing one dependency per line.
    fn parse_requires_block(&mut self) -> ParseResult<Vec<Stmt<'a>>> {
        let mut deps = Vec::new();

        loop {
            // Stop at next block header or EOF
            if self.is_at_end() {
                break;
            }
            if matches!(self.peek().kind, TokenType::BlockHeader { .. }) {
                break;
            }

            // Skip whitespace tokens
            if self.check(&TokenType::Indent)
                || self.check(&TokenType::Dedent)
                || self.check(&TokenType::Newline)
            {
                self.advance();
                continue;
            }

            // Each dependency line starts with an article ("The")
            if matches!(self.peek().kind, TokenType::Article(_)) {
                let dep = self.parse_require_line()?;
                deps.push(dep);
                continue;
            }

            // Skip unexpected tokens (defensive)
            self.advance();
        }

        Ok(deps)
    }

    /// Parse a single dependency line:
    /// `The "serde" crate version "1.0" with features "derive" and "std" for serialization.`
    fn parse_require_line(&mut self) -> ParseResult<Stmt<'a>> {
        let start_span = self.current_span();

        // Expect article "The"
        if !matches!(self.peek().kind, TokenType::Article(_)) {
            return Err(crate::error::ParseError {
                kind: crate::error::ParseErrorKind::Custom(
                    "Expected 'The' to begin a dependency declaration.".to_string(),
                ),
                span: self.current_span(),
            });
        }
        self.advance(); // consume "The"

        // Expect string literal for crate name
        let crate_name = if let TokenType::StringLiteral(sym) = self.peek().kind {
            let s = sym;
            self.advance();
            s
        } else {
            return Err(crate::error::ParseError {
                kind: crate::error::ParseErrorKind::Custom(
                    "Expected a string literal for the crate name, e.g. \"serde\".".to_string(),
                ),
                span: self.current_span(),
            });
        };

        // Expect word "crate"
        if !self.check_word("crate") {
            return Err(crate::error::ParseError {
                kind: crate::error::ParseErrorKind::Custom(
                    "Expected the word 'crate' after the crate name.".to_string(),
                ),
                span: self.current_span(),
            });
        }
        self.advance(); // consume "crate"

        // Expect word "version"
        if !self.check_word("version") {
            return Err(crate::error::ParseError {
                kind: crate::error::ParseErrorKind::Custom(
                    "Expected 'version' after 'crate'.".to_string(),
                ),
                span: self.current_span(),
            });
        }
        self.advance(); // consume "version"

        // Expect string literal for version
        let version = if let TokenType::StringLiteral(sym) = self.peek().kind {
            let s = sym;
            self.advance();
            s
        } else {
            return Err(crate::error::ParseError {
                kind: crate::error::ParseErrorKind::Custom(
                    "Expected a string literal for the version, e.g. \"1.0\".".to_string(),
                ),
                span: self.current_span(),
            });
        };

        // Optional: "with features ..."
        let mut features = Vec::new();
        if self.check_preposition_is("with") {
            self.advance(); // consume "with"

            // Expect word "features"
            if !self.check_word("features") {
                return Err(crate::error::ParseError {
                    kind: crate::error::ParseErrorKind::Custom(
                        "Expected 'features' after 'with'.".to_string(),
                    ),
                    span: self.current_span(),
                });
            }
            self.advance(); // consume "features"

            // Parse first feature string
            if let TokenType::StringLiteral(sym) = self.peek().kind {
                features.push(sym);
                self.advance();
            } else {
                return Err(crate::error::ParseError {
                    kind: crate::error::ParseErrorKind::Custom(
                        "Expected a string literal for a feature name.".to_string(),
                    ),
                    span: self.current_span(),
                });
            }

            // Parse additional features separated by "and"
            while self.check(&TokenType::And) {
                self.advance(); // consume "and"
                if let TokenType::StringLiteral(sym) = self.peek().kind {
                    features.push(sym);
                    self.advance();
                } else {
                    return Err(crate::error::ParseError {
                        kind: crate::error::ParseErrorKind::Custom(
                            "Expected a string literal for a feature name after 'and'.".to_string(),
                        ),
                        span: self.current_span(),
                    });
                }
            }
        }

        // Optional: "for <description...>" — consume until period
        if self.check(&TokenType::For) {
            self.advance(); // consume "for"
            while !self.check(&TokenType::Period) && !self.check(&TokenType::EOF)
                && !self.check(&TokenType::Newline)
                && !matches!(self.peek().kind, TokenType::BlockHeader { .. })
            {
                self.advance();
            }
        }

        // Consume trailing period
        if self.check(&TokenType::Period) {
            self.advance();
        }

        let end_span = self.previous().span;

        Ok(Stmt::Require {
            crate_name,
            version,
            features,
            span: crate::token::Span::new(start_span.start, end_span.end),
        })
    }

    /// Phase 54: Parse Stop statement
    /// Syntax: Stop handle.
    fn parse_stop_statement(&mut self) -> ParseResult<Stmt<'a>> {
        self.advance(); // consume "Stop"

        let handle = self.parse_imperative_expr()?;

        Ok(Stmt::StopTask { handle })
    }

    /// Phase 54: Parse Select statement
    /// Syntax:
    /// Await the first of:
    ///     Receive x from pipe:
    ///         ...
    ///     After N seconds:
    ///         ...
    fn parse_select_statement(&mut self) -> ParseResult<Stmt<'a>> {
        use crate::ast::stmt::SelectBranch;

        self.advance(); // consume "Await"

        // Expect "the"
        if !self.check_article() {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "the".to_string() },
                span: self.current_span(),
            });
        }
        self.advance();

        // Expect "first"
        if !self.check_word("first") {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "first".to_string() },
                span: self.current_span(),
            });
        }
        self.advance();

        // Expect "of"
        if !self.check_preposition_is("of") {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "of".to_string() },
                span: self.current_span(),
            });
        }
        self.advance();

        // Expect colon
        if !self.check(&TokenType::Colon) {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: ":".to_string() },
                span: self.current_span(),
            });
        }
        self.advance();

        // Expect indent
        if !self.check(&TokenType::Indent) {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedStatement,
                span: self.current_span(),
            });
        }
        self.advance();

        // Parse branches
        let mut branches = Vec::new();
        while !self.check(&TokenType::Dedent) && !self.is_at_end() {
            let branch = self.parse_select_branch()?;
            branches.push(branch);
        }

        // Consume dedent
        if self.check(&TokenType::Dedent) {
            self.advance();
        }

        Ok(Stmt::Select { branches })
    }

    /// Phase 54: Parse a single select branch
    fn parse_select_branch(&mut self) -> ParseResult<crate::ast::stmt::SelectBranch<'a>> {
        use crate::ast::stmt::SelectBranch;

        if self.check(&TokenType::Receive) {
            self.advance(); // consume "Receive"

            let var = match &self.tokens[self.current].kind {
                TokenType::ProperName(sym) | TokenType::Noun(sym) | TokenType::Adjective(sym) => {
                    let s = *sym;
                    self.advance();
                    s
                }
                _ => {
                    return Err(ParseError {
                        kind: ParseErrorKind::ExpectedKeyword { keyword: "variable name".to_string() },
                        span: self.current_span(),
                    });
                }
            };

            if !self.check(&TokenType::From) && !self.check_preposition_is("from") {
                return Err(ParseError {
                    kind: ParseErrorKind::ExpectedKeyword { keyword: "from".to_string() },
                    span: self.current_span(),
                });
            }
            self.advance();

            let pipe = self.parse_imperative_expr()?;

            // Expect colon
            if !self.check(&TokenType::Colon) {
                return Err(ParseError {
                    kind: ParseErrorKind::ExpectedKeyword { keyword: ":".to_string() },
                    span: self.current_span(),
                });
            }
            self.advance();

            // Parse body
            let body = self.parse_indented_block()?;

            Ok(SelectBranch::Receive { var, pipe, body })
        } else if self.check_word("after") {
            self.advance(); // consume "After"

            let milliseconds = self.parse_imperative_expr()?;

            // Skip "seconds" or "milliseconds" if present
            if self.check_word("seconds") || self.check_word("milliseconds") {
                self.advance();
            }

            // Expect colon
            if !self.check(&TokenType::Colon) {
                return Err(ParseError {
                    kind: ParseErrorKind::ExpectedKeyword { keyword: ":".to_string() },
                    span: self.current_span(),
                });
            }
            self.advance();

            // Parse body
            let body = self.parse_indented_block()?;

            Ok(SelectBranch::Timeout { milliseconds, body })
        } else {
            Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "Receive or After".to_string() },
                span: self.current_span(),
            })
        }
    }

    /// Phase 54: Parse an indented block of statements
    /// Depth-guarded wrapper: nested blocks recurse here once per level, so
    /// a block pyramid errors gracefully instead of overflowing the parser.
    fn parse_indented_block(&mut self) -> ParseResult<crate::ast::stmt::Block<'a>> {
        self.enter_recursion()?;
        let result = self.parse_indented_block_inner();
        self.leave_recursion();
        result
    }

    fn parse_indented_block_inner(&mut self) -> ParseResult<crate::ast::stmt::Block<'a>> {
        // Expect indent
        if !self.check(&TokenType::Indent) {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedStatement,
                span: self.current_span(),
            });
        }
        self.advance();

        let mut stmts = Vec::new();
        while !self.check(&TokenType::Dedent) && !self.is_at_end() {
            let stmt = self.parse_statement()?;
            stmts.push(stmt);
            if self.check(&TokenType::Period) {
                self.advance();
            }
        }

        // Consume dedent
        if self.check(&TokenType::Dedent) {
            self.advance();
        }

        let block = self.ctx.stmts.expect("imperative arenas not initialized")
            .alloc_slice(stmts.into_iter());

        Ok(block)
    }

    fn parse_give_statement(&mut self) -> ParseResult<Stmt<'a>> {
        self.advance(); // consume "Give"

        // Parse the object being given: "x" or "the data"
        let object = self.parse_imperative_expr()?;

        // Expect "to" preposition (can be TokenType::To when followed by verb-like word)
        if !self.check_to_preposition() {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "to".to_string() },
                span: self.current_span(),
            });
        }
        self.advance(); // consume "to"

        // Parse the recipient: "processor" or "the console"
        let recipient = self.parse_imperative_expr()?;

        // Mark variable as Moved after Give
        if let Expr::Identifier(sym) = object {
            self.world_state.set_ownership_by_var(*sym, crate::drs::OwnershipState::Moved);
        }

        Ok(Stmt::Give { object, recipient })
    }

    fn parse_show_statement(&mut self) -> ParseResult<Stmt<'a>> {
        self.advance(); // consume "Show"

        // Parse the object being shown - use parse_condition to support
        // comparisons (x is less than y) and boolean operators (a and b)
        let object = self.parse_condition()?;

        // Optional "to" preposition - if not present, default to "show" function
        // Note: Use check_to_preposition() to handle both TokenType::To (when followed by verb)
        // and TokenType::Preposition("to")
        let recipient = if self.check_to_preposition() {
            self.advance(); // consume "to"

            // Phase 10: "Show x to console." or "Show x to the console."
            // is idiomatic for printing to stdout - use default show function
            if self.check_article() {
                self.advance(); // skip "the"
            }
            if self.check(&TokenType::Console) {
                self.advance(); // consume "console"
                let show_sym = self.interner.intern("show");
                self.ctx.alloc_imperative_expr(Expr::Identifier(show_sym))
            } else {
                // Parse the recipient: custom function
                self.parse_imperative_expr()?
            }
        } else {
            // Default recipient: the runtime "show" function
            let show_sym = self.interner.intern("show");
            self.ctx.alloc_imperative_expr(Expr::Identifier(show_sym))
        };

        // Mark variable as Borrowed after Show
        if let Expr::Identifier(sym) = object {
            self.world_state.set_ownership_by_var(*sym, crate::drs::OwnershipState::Borrowed);
        }

        Ok(Stmt::Show { object, recipient })
    }

    /// Phase 43D: Parse Push statement for collection operations
    /// Syntax: Push x to items.
    fn parse_push_statement(&mut self) -> ParseResult<Stmt<'a>> {
        self.advance(); // consume "Push"

        // Parse the value(s) being pushed — `Push a, b, c to xs.` appends each
        // in order (desugars to one Push per element).
        let mut values = vec![self.parse_imperative_expr()?];
        while self.check(&TokenType::Comma) {
            self.advance(); // consume ","
            values.push(self.parse_imperative_expr()?);
        }

        // Expect "to" (can be keyword or preposition)
        if !self.check(&TokenType::To) && !self.check_preposition_is("to") {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "to".to_string() },
                span: self.current_span(),
            });
        }
        self.advance(); // consume "to"

        // Parse the collection
        let collection = self.parse_imperative_expr()?;

        if values.len() == 1 {
            Ok(self.desugar_place_push(values[0], collection))
        } else {
            let mut pushes = Vec::with_capacity(values.len());
            for value in values {
                pushes.push(self.desugar_place_push(value, collection));
            }
            let body = self.ctx.stmts.expect("imperative arenas not initialized")
                .alloc_slice(pushes.into_iter());
            Ok(Stmt::Splice { body })
        }
    }

    /// Phase 43D: Parse Pop statement for collection operations
    /// Syntax: Pop from items. OR Pop from items into y.
    fn parse_pop_statement(&mut self) -> ParseResult<Stmt<'a>> {
        self.advance(); // consume "Pop"

        // Expect "from" - can be keyword token or preposition
        if !self.check(&TokenType::From) && !self.check_preposition_is("from") {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "from".to_string() },
                span: self.current_span(),
            });
        }
        self.advance(); // consume "from"

        // Parse the collection
        let collection = self.parse_imperative_expr()?;

        // Check for optional "into" binding (can be Into keyword or preposition)
        let into = if self.check(&TokenType::Into) || self.check_preposition_is("into") {
            self.advance(); // consume "into"

            // Parse variable name
            if let TokenType::Noun(sym) | TokenType::ProperName(sym) = &self.peek().kind {
                let sym = *sym;
                self.advance();
                Some(sym)
            } else if let Some(token) = self.tokens.get(self.current) {
                // Also handle identifier-like tokens
                let sym = token.lexeme;
                self.advance();
                Some(sym)
            } else {
                return Err(ParseError {
                    kind: ParseErrorKind::ExpectedIdentifier,
                    span: self.current_span(),
                });
            }
        } else {
            None
        };

        Ok(Stmt::Pop { collection, into })
    }

    /// Parse Add statement for Set insertion
    /// Syntax: Add x to set.
    fn parse_add_statement(&mut self) -> ParseResult<Stmt<'a>> {
        self.advance(); // consume "Add"

        // Parse the value to add
        let value = self.parse_imperative_expr()?;

        // Expect "to" preposition
        if !self.check_preposition_is("to") && !self.check(&TokenType::To) {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "to".to_string() },
                span: self.current_span(),
            });
        }
        self.advance(); // consume "to"

        // Parse the collection expression
        let collection = self.parse_imperative_expr()?;

        Ok(Stmt::Add { value, collection })
    }

    /// Parse Remove statement for Set deletion
    /// Syntax: Remove x from set.
    fn parse_remove_statement(&mut self) -> ParseResult<Stmt<'a>> {
        self.advance(); // consume "Remove"

        // Parse the value to remove
        let value = self.parse_imperative_expr()?;

        // Expect "from" preposition
        if !self.check(&TokenType::From) && !self.check_preposition_is("from") {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "from".to_string() },
                span: self.current_span(),
            });
        }
        self.advance(); // consume "from"

        // Parse the collection expression
        let collection = self.parse_imperative_expr()?;

        Ok(Stmt::Remove { value, collection })
    }

    /// Phase 10: Parse Read statement for console/file input
    /// Syntax: Read <var> from the console.
    ///         Read <var> from file <path>.
    fn parse_read_statement(&mut self) -> ParseResult<Stmt<'a>> {
        self.advance(); // consume "Read"

        // Get the variable name
        let var = self.expect_identifier()?;

        // Expect "from" preposition
        if !self.check(&TokenType::From) && !self.check_preposition_is("from") {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "from".to_string() },
                span: self.current_span(),
            });
        }
        self.advance(); // consume "from"

        // Skip optional article "the"
        if self.check_article() {
            self.advance();
        }

        // Determine source: console or file
        let source = if self.check(&TokenType::Console) {
            self.advance(); // consume "console"
            ReadSource::Console
        } else if self.check(&TokenType::File) {
            self.advance(); // consume "file"
            let path = self.parse_imperative_expr()?;
            ReadSource::File(path)
        } else {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "console or file".to_string() },
                span: self.current_span(),
            });
        };

        Ok(Stmt::ReadFrom { var, source })
    }

    /// Phase 10: Parse Write statement for file output
    /// Syntax: Write <content> to file <path>.
    fn parse_write_statement(&mut self) -> ParseResult<Stmt<'a>> {
        self.advance(); // consume "Write"

        // Parse the content expression
        let content = self.parse_imperative_expr()?;

        // Expect "to" (can be keyword or preposition)
        if !self.check(&TokenType::To) && !self.check_preposition_is("to") {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "to".to_string() },
                span: self.current_span(),
            });
        }
        self.advance(); // consume "to"

        // Expect "file" keyword
        if !self.check(&TokenType::File) {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "file".to_string() },
                span: self.current_span(),
            });
        }
        self.advance(); // consume "file"

        // Parse the path expression
        let path = self.parse_imperative_expr()?;

        Ok(Stmt::WriteFile { content, path })
    }

    /// Phase 8.5: Parse Zone statement for memory arena blocks
    /// Syntax variants:
    ///   - Inside a new zone called "Scratch":
    ///   - Inside a zone called "Buffer" of size 1 MB:
    ///   - Inside a zone called "Data" mapped from "file.bin":
    fn parse_zone_statement(&mut self) -> ParseResult<Stmt<'a>> {
        self.advance(); // consume "Inside"

        // Optional article "a"
        if self.check_article() {
            self.advance();
        }

        // Optional "new"
        if self.check(&TokenType::New) {
            self.advance();
        }

        // Expect "zone"
        if !self.check(&TokenType::Zone) {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "zone".to_string() },
                span: self.current_span(),
            });
        }
        self.advance(); // consume "zone"

        // Expect "called"
        if !self.check(&TokenType::Called) {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "called".to_string() },
                span: self.current_span(),
            });
        }
        self.advance(); // consume "called"

        // Parse zone name (can be string literal or identifier)
        let name = match &self.peek().kind {
            TokenType::StringLiteral(sym) => {
                let s = *sym;
                self.advance();
                s
            }
            TokenType::ProperName(sym) | TokenType::Noun(sym) | TokenType::Adjective(sym) => {
                let s = *sym;
                self.advance();
                s
            }
            _ => {
                // Try to use the lexeme directly as an identifier
                let token = self.peek().clone();
                self.advance();
                token.lexeme
            }
        };

        let mut capacity = None;
        let mut source_file = None;

        // Check for "mapped from" (file-backed zone)
        if self.check(&TokenType::Mapped) {
            self.advance(); // consume "mapped"

            // Expect "from"
            if !self.check(&TokenType::From) && !self.check_preposition_is("from") {
                return Err(ParseError {
                    kind: ParseErrorKind::ExpectedKeyword { keyword: "from".to_string() },
                    span: self.current_span(),
                });
            }
            self.advance(); // consume "from"

            // Parse file path — a string literal, or a variable holding the path
            // (the path is often known only at runtime, e.g. a function parameter).
            if let TokenType::StringLiteral(path) = &self.peek().kind {
                let p = *path;
                self.advance();
                source_file = Some(crate::ast::stmt::ZoneSource::Literal(p));
            } else {
                let var = self.expect_identifier()?;
                source_file = Some(crate::ast::stmt::ZoneSource::Variable(var));
            }
        }
        // Check for "of size N Unit" (sized heap zone)
        else if self.check_of_preposition() {
            self.advance(); // consume "of"

            // Expect "size"
            if !self.check(&TokenType::Size) {
                return Err(ParseError {
                    kind: ParseErrorKind::ExpectedKeyword { keyword: "size".to_string() },
                    span: self.current_span(),
                });
            }
            self.advance(); // consume "size"

            // Parse size number
            let size_value = match &self.peek().kind {
                TokenType::Number(sym) => {
                    let num_str = self.interner.resolve(*sym).to_string();
                    let val = self.parse_i64_numeral(&num_str)? as usize;
                    self.advance();
                    val
                }
                TokenType::Cardinal(n) => {
                    let val = *n as usize;
                    self.advance();
                    val
                }
                _ => {
                    return Err(ParseError {
                        kind: ParseErrorKind::ExpectedNumber,
                        span: self.current_span(),
                    });
                }
            };

            // Parse unit (KB, MB, GB, or B)
            let unit_multiplier = self.parse_size_unit()?;
            capacity = Some(size_value * unit_multiplier);
        }

        // Expect colon
        if !self.check(&TokenType::Colon) {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: ":".to_string() },
                span: self.current_span(),
            });
        }
        self.advance(); // consume ":"

        // Expect indent
        if !self.check(&TokenType::Indent) {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedStatement,
                span: self.current_span(),
            });
        }
        self.advance(); // consume Indent

        // Parse body statements
        let mut body_stmts = Vec::new();
        while !self.check(&TokenType::Dedent) && !self.is_at_end() {
            let stmt = self.parse_statement()?;
            body_stmts.push(stmt);
            if self.check(&TokenType::Period) {
                self.advance();
            }
        }

        // Consume dedent
        if self.check(&TokenType::Dedent) {
            self.advance();
        }

        let body = self.ctx.stmts.expect("imperative arenas not initialized")
            .alloc_slice(body_stmts.into_iter());

        Ok(Stmt::Zone { name, capacity, source_file, body })
    }

    /// Parse size unit (B, KB, MB, GB) and return multiplier
    fn parse_size_unit(&mut self) -> ParseResult<usize> {
        let token = self.peek().clone();
        let unit_str = self.interner.resolve(token.lexeme).to_uppercase();
        self.advance();

        match unit_str.as_str() {
            "B" | "BYTES" | "BYTE" => Ok(1),
            "KB" | "KILOBYTE" | "KILOBYTES" => Ok(1024),
            "MB" | "MEGABYTE" | "MEGABYTES" => Ok(1024 * 1024),
            "GB" | "GIGABYTE" | "GIGABYTES" => Ok(1024 * 1024 * 1024),
            _ => Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword {
                    keyword: "size unit (B, KB, MB, GB)".to_string(),
                },
                span: token.span,
            }),
        }
    }

    /// Phase 9: Parse concurrent execution block (async, I/O-bound)
    ///
    /// Syntax:
    /// ```logos
    /// Attempt all of the following:
    ///     Call fetch_user with id.
    ///     Call fetch_orders with id.
    /// ```
    fn parse_concurrent_block(&mut self) -> ParseResult<Stmt<'a>> {
        self.advance(); // consume "Attempt"

        // Expect "all"
        if !self.check(&TokenType::All) {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "all".to_string() },
                span: self.current_span(),
            });
        }
        self.advance(); // consume "all"

        // Expect "of" (preposition)
        if !self.check_of_preposition() {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "of".to_string() },
                span: self.current_span(),
            });
        }
        self.advance(); // consume "of"

        // Expect "the"
        if !self.check_article() {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "the".to_string() },
                span: self.current_span(),
            });
        }
        self.advance(); // consume "the"

        // Expect "following"
        if !self.check(&TokenType::Following) {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "following".to_string() },
                span: self.current_span(),
            });
        }
        self.advance(); // consume "following"

        // Expect colon
        if !self.check(&TokenType::Colon) {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: ":".to_string() },
                span: self.current_span(),
            });
        }
        self.advance(); // consume ":"

        // Expect indent
        if !self.check(&TokenType::Indent) {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedStatement,
                span: self.current_span(),
            });
        }
        self.advance(); // consume Indent

        // Parse body statements
        let mut task_stmts = Vec::new();
        while !self.check(&TokenType::Dedent) && !self.is_at_end() {
            let stmt = self.parse_statement()?;
            task_stmts.push(stmt);
            if self.check(&TokenType::Period) {
                self.advance();
            }
        }

        // Consume dedent
        if self.check(&TokenType::Dedent) {
            self.advance();
        }

        let tasks = self.ctx.stmts.expect("imperative arenas not initialized")
            .alloc_slice(task_stmts.into_iter());

        Ok(Stmt::Concurrent { tasks })
    }

    /// Phase 9: Parse parallel execution block (CPU-bound)
    ///
    /// Syntax:
    /// ```logos
    /// Simultaneously:
    ///     Call compute_hash with data1.
    ///     Call compute_hash with data2.
    /// ```
    fn parse_parallel_block(&mut self) -> ParseResult<Stmt<'a>> {
        self.advance(); // consume "Simultaneously"

        // Expect colon
        if !self.check(&TokenType::Colon) {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: ":".to_string() },
                span: self.current_span(),
            });
        }
        self.advance(); // consume ":"

        // Expect indent
        if !self.check(&TokenType::Indent) {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedStatement,
                span: self.current_span(),
            });
        }
        self.advance(); // consume Indent

        // Parse body statements
        let mut task_stmts = Vec::new();
        while !self.check(&TokenType::Dedent) && !self.is_at_end() {
            let stmt = self.parse_statement()?;
            task_stmts.push(stmt);
            if self.check(&TokenType::Period) {
                self.advance();
            }
        }

        // Consume dedent
        if self.check(&TokenType::Dedent) {
            self.advance();
        }

        let tasks = self.ctx.stmts.expect("imperative arenas not initialized")
            .alloc_slice(task_stmts.into_iter());

        Ok(Stmt::Parallel { tasks })
    }

    /// Phase 33: Parse Inspect statement for pattern matching
    /// Syntax: Inspect target:
    ///             If it is a Variant [(bindings)]:
    ///                 body...
    ///             Otherwise:
    ///                 body...
    fn parse_inspect_statement(&mut self) -> ParseResult<Stmt<'a>> {
        self.advance(); // consume "Inspect"

        // Parse target expression
        let target = self.parse_imperative_expr()?;

        // Expect colon
        if !self.check(&TokenType::Colon) {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: ":".to_string() },
                span: self.current_span(),
            });
        }
        self.advance(); // consume ":"

        // Expect indent
        if !self.check(&TokenType::Indent) {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedStatement,
                span: self.current_span(),
            });
        }
        self.advance(); // consume Indent

        let mut arms = Vec::new();
        let mut has_otherwise = false;

        // Parse match arms until dedent
        while !self.check(&TokenType::Dedent) && !self.is_at_end() {
            if self.check(&TokenType::Otherwise) {
                // Parse "Otherwise:" default arm
                self.advance(); // consume "Otherwise"

                if !self.check(&TokenType::Colon) {
                    return Err(ParseError {
                        kind: ParseErrorKind::ExpectedKeyword { keyword: ":".to_string() },
                        span: self.current_span(),
                    });
                }
                self.advance(); // consume ":"

                // Handle both inline (Otherwise: stmt.) and block body
                let body_stmts = if self.check(&TokenType::Indent) {
                    self.advance(); // consume Indent
                    let mut stmts = Vec::new();
                    while !self.check(&TokenType::Dedent) && !self.is_at_end() {
                        let stmt = self.parse_statement()?;
                        stmts.push(stmt);
                        if self.check(&TokenType::Period) {
                            self.advance();
                        }
                    }
                    if self.check(&TokenType::Dedent) {
                        self.advance();
                    }
                    stmts
                } else {
                    // Inline body: "Otherwise: Show x."
                    let stmt = self.parse_statement()?;
                    if self.check(&TokenType::Period) {
                        self.advance();
                    }
                    vec![stmt]
                };

                let body = self.ctx.stmts.expect("imperative arenas not initialized")
                    .alloc_slice(body_stmts.into_iter());

                arms.push(MatchArm { enum_name: None, variant: None, bindings: vec![], body });
                has_otherwise = true;
                break;
            }

            if self.check(&TokenType::If) {
                // Parse "If it is a VariantName [(bindings)]:"
                let arm = self.parse_match_arm()?;
                arms.push(arm);
            } else if self.check(&TokenType::When) || self.check_word("When") {
                // Parse "When Variant [(bindings)]:" (concise syntax)
                let arm = self.parse_when_arm()?;
                arms.push(arm);
            } else if self.check(&TokenType::Newline) {
                // Skip newlines between arms
                self.advance();
            } else {
                // Skip unexpected tokens
                self.advance();
            }
        }

        // Consume final dedent
        if self.check(&TokenType::Dedent) {
            self.advance();
        }

        Ok(Stmt::Inspect { target, arms, has_otherwise })
    }

    /// Parse a single match arm: "If it is a Variant [(field: binding)]:"
    fn parse_match_arm(&mut self) -> ParseResult<MatchArm<'a>> {
        self.advance(); // consume "If"

        // Expect "it"
        if !self.check_word("it") {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "it".to_string() },
                span: self.current_span(),
            });
        }
        self.advance(); // consume "it"

        // Expect "is"
        if !self.check(&TokenType::Is) {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "is".to_string() },
                span: self.current_span(),
            });
        }
        self.advance(); // consume "is"

        // Consume article "a" or "an"
        if self.check_article() {
            self.advance();
        }

        // Get variant name
        let variant = self.expect_identifier()?;

        // Look up the enum name for this variant
        let enum_name = self.find_variant(variant);

        // Optional: "(field)" or "(field: binding)" or "(f1, f2: b2)"
        let bindings = if self.check(&TokenType::LParen) {
            self.parse_pattern_bindings()?
        } else {
            vec![]
        };

        // Expect colon
        if !self.check(&TokenType::Colon) {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: ":".to_string() },
                span: self.current_span(),
            });
        }
        self.advance(); // consume ":"

        // Expect indent
        if !self.check(&TokenType::Indent) {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedStatement,
                span: self.current_span(),
            });
        }
        self.advance(); // consume Indent

        // Parse body statements
        let mut body_stmts = Vec::new();
        while !self.check(&TokenType::Dedent) && !self.is_at_end() {
            let stmt = self.parse_statement()?;
            body_stmts.push(stmt);
            if self.check(&TokenType::Period) {
                self.advance();
            }
        }

        // Consume dedent
        if self.check(&TokenType::Dedent) {
            self.advance();
        }

        let body = self.ctx.stmts.expect("imperative arenas not initialized")
            .alloc_slice(body_stmts.into_iter());

        Ok(MatchArm { enum_name, variant: Some(variant), bindings, body })
    }

    /// Parse a concise match arm: "When Variant [(bindings)]:" or "When Variant: stmt."
    fn parse_when_arm(&mut self) -> ParseResult<MatchArm<'a>> {
        self.advance(); // consume "When"

        // Get variant name
        let variant = self.expect_identifier()?;

        // Look up the enum name and variant definition for this variant
        let (enum_name, variant_fields) = self.type_registry
            .as_ref()
            .and_then(|r| r.find_variant(variant).map(|(enum_name, vdef)| {
                let fields: Vec<_> = vdef.fields.iter().map(|f| f.name).collect();
                (Some(enum_name), fields)
            }))
            .unwrap_or((None, vec![]));

        // Optional: "(binding)" or "(b1, b2)" - positional bindings
        let bindings = if self.check(&TokenType::LParen) {
            let raw_bindings = self.parse_when_bindings()?;
            // Map positional bindings to actual field names
            raw_bindings.into_iter().enumerate().map(|(i, binding)| {
                let field = variant_fields.get(i).copied().unwrap_or(binding);
                (field, binding)
            }).collect()
        } else {
            vec![]
        };

        // Expect colon
        if !self.check(&TokenType::Colon) {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: ":".to_string() },
                span: self.current_span(),
            });
        }
        self.advance(); // consume ":"

        // Handle both inline body (When Variant: stmt.) and block body
        let body_stmts = if self.check(&TokenType::Indent) {
            self.advance(); // consume Indent
            let mut stmts = Vec::new();
            while !self.check(&TokenType::Dedent) && !self.is_at_end() {
                let stmt = self.parse_statement()?;
                stmts.push(stmt);
                if self.check(&TokenType::Period) {
                    self.advance();
                }
            }
            if self.check(&TokenType::Dedent) {
                self.advance();
            }
            stmts
        } else {
            // Inline body: "When Red: Show x."
            let stmt = self.parse_statement()?;
            if self.check(&TokenType::Period) {
                self.advance();
            }
            vec![stmt]
        };

        let body = self.ctx.stmts.expect("imperative arenas not initialized")
            .alloc_slice(body_stmts.into_iter());

        Ok(MatchArm { enum_name, variant: Some(variant), bindings, body })
    }

    /// Parse concise When bindings: "(r)" or "(w, h)" - just binding variable names
    fn parse_when_bindings(&mut self) -> ParseResult<Vec<Symbol>> {
        self.advance(); // consume '('
        let mut bindings = Vec::new();

        loop {
            let binding = self.expect_identifier()?;
            bindings.push(binding);

            if !self.check(&TokenType::Comma) {
                break;
            }
            self.advance(); // consume ','
        }

        if !self.check(&TokenType::RParen) {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: ")".to_string() },
                span: self.current_span(),
            });
        }
        self.advance(); // consume ')'

        Ok(bindings)
    }

    /// Parse pattern bindings: "(field)" or "(field: binding)" or "(f1, f2: b2)"
    fn parse_pattern_bindings(&mut self) -> ParseResult<Vec<(Symbol, Symbol)>> {
        self.advance(); // consume '('
        let mut bindings = Vec::new();

        loop {
            let field = self.expect_identifier()?;
            let binding = if self.check(&TokenType::Colon) {
                self.advance(); // consume ":"
                self.expect_identifier()?
            } else {
                field // field name = binding name
            };
            bindings.push((field, binding));

            if !self.check(&TokenType::Comma) {
                break;
            }
            self.advance(); // consume ','
        }

        if !self.check(&TokenType::RParen) {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: ")".to_string() },
                span: self.current_span(),
            });
        }
        self.advance(); // consume ')'

        Ok(bindings)
    }

    /// Parse constructor fields: "with field1 value1 [and field2 value2]..."
    /// Example: "with radius 10" or "with x 10 and y 20"
    /// Used for both variant constructors and struct initialization
    fn parse_constructor_fields(&mut self) -> ParseResult<Vec<(Symbol, &'a Expr<'a>)>> {
        use crate::ast::Expr;
        let mut fields = Vec::new();

        // Consume "with"
        self.advance();

        loop {
            // Parse field name
            let field_name = self.expect_identifier()?;

            // Parse field value expression — use parse_comparison to stop before
            // "and"/"or" which serve as field separators in constructor syntax
            let value = self.parse_comparison()?;

            fields.push((field_name, value));

            // Check for "and" to continue
            if self.check(&TokenType::And) {
                self.advance(); // consume "and"
                continue;
            }
            break;
        }

        Ok(fields)
    }

    /// Alias for variant constructors (backwards compat)
    fn parse_variant_constructor_fields(&mut self) -> ParseResult<Vec<(Symbol, &'a Expr<'a>)>> {
        self.parse_constructor_fields()
    }

    /// Alias for struct initialization
    fn parse_struct_init_fields(&mut self) -> ParseResult<Vec<(Symbol, &'a Expr<'a>)>> {
        self.parse_constructor_fields()
    }

    /// Phase 34: Parse generic type arguments for constructor instantiation
    /// Parses "of Int" or "of Int and Text" after a generic type name
    /// Returns empty Vec for non-generic types
    fn parse_generic_type_args(&mut self, type_name: Symbol) -> ParseResult<Vec<TypeExpr<'a>>> {
        // Only parse type args if the type is a known generic
        if !self.is_generic_type(type_name) {
            return Ok(vec![]);
        }

        // Expect "of" preposition
        if !self.check_preposition_is("of") {
            return Ok(vec![]);  // Generic type without arguments - will use defaults
        }
        self.advance(); // consume "of"

        let mut type_args = Vec::new();
        loop {
            // Bug fix: Parse full type expression to support nested types like "Seq of (Seq of Int)"
            let type_arg = self.parse_type_expression()?;
            type_args.push(type_arg);

            // Check for "and" or "to" to continue (for multi-param generics like "Map of Text to Int")
            if self.check(&TokenType::And) || self.check_to_preposition() {
                self.advance(); // consume separator
                continue;
            }
            break;
        }

        Ok(type_args)
    }

    /// Skip type definition content until next block header
    /// Used for TypeDef blocks (## A Point has:, ## A Color is one of:)
    /// The actual parsing is done by DiscoveryPass
    fn skip_type_def_content(&mut self) {
        while !self.is_at_end() {
            // Stop at next block header
            if matches!(
                self.tokens.get(self.current),
                Some(Token { kind: TokenType::BlockHeader { .. }, .. })
            ) {
                break;
            }
            self.advance();
        }
    }

    /// Phase 63: Parse theorem block
    /// Syntax:
    ///   ## Theorem: Name
    ///   Given: Premise 1.
    ///   Given: Premise 2.
    ///   Prove: Goal.
    ///   Proof: Auto.
    fn parse_theorem_block(&mut self) -> ParseResult<Stmt<'a>> {
        use crate::ast::theorem::{TheoremBlock, ProofStrategy};

        // Skip newlines and indentation
        self.skip_whitespace_tokens();

        // Parse theorem name: expect "Name" after the ##Theorem header
        // The header has already been consumed; expect Colon then Identifier
        // Note: In some cases the colon might have been consumed with the header.
        // Let's be flexible and check for both.
        if self.check(&TokenType::Colon) {
            self.advance();
        }

        // Skip whitespace again
        self.skip_whitespace_tokens();

        // Get theorem name - should be an identifier (Noun, ProperName, etc.)
        let name = if let Some(token) = self.tokens.get(self.current) {
            match &token.kind {
                TokenType::Noun(_)
                | TokenType::ProperName(_)
                | TokenType::Verb { .. }
                | TokenType::Adjective(_) => {
                    let name = self.interner.resolve(token.lexeme).to_string();
                    self.advance();
                    name
                }
                _ => {
                    // Use the lexeme directly for unrecognized tokens
                    let lexeme = self.interner.resolve(token.lexeme);
                    if !lexeme.is_empty() && lexeme.chars().next().map(|c| c.is_alphanumeric()).unwrap_or(false) {
                        let name = lexeme.to_string();
                        self.advance();
                        name
                    } else {
                        "Anonymous".to_string()
                    }
                }
            }
        } else {
            "Anonymous".to_string()
        };

        self.skip_whitespace_tokens();

        // Skip period after name if present
        if self.check(&TokenType::Period) {
            self.advance();
        }

        self.skip_whitespace_tokens();

        // Parse premises (Given: statements)
        // Each premise is a sentence that can introduce referents for subsequent premises
        let mut premises = Vec::new();
        let mut premise_names: Vec<Option<String>> = Vec::new();
        while self.check(&TokenType::Given) {
            self.advance(); // consume "Given"

            self.skip_whitespace_tokens();

            // Optional premise NAME in parentheses: `Given (h): …` names this premise
            // `h`, so a `Proof:` script can say `cases h` instead of the positional `hp0`.
            let mut this_name: Option<String> = None;
            if self.check(&TokenType::LParen) {
                self.advance();
                self.skip_whitespace_tokens();
                if let Some(token) = self.tokens.get(self.current) {
                    if !matches!(token.kind, TokenType::RParen) {
                        this_name = Some(self.interner.resolve(token.lexeme).to_string());
                        self.advance();
                    }
                }
                self.skip_whitespace_tokens();
                if self.check(&TokenType::RParen) {
                    self.advance();
                }
                self.skip_whitespace_tokens();
            }
            premise_names.push(this_name);

            // Expect colon
            if self.check(&TokenType::Colon) {
                self.advance();
            }

            self.skip_whitespace_tokens();

            // Parse the logic expression for this premise. In pragmatic mode
            // a leading weak scalar (some/most/many) carries its Horn-scale
            // implicature, exactly as in `parse_pragmatic`.
            let scalar_trigger = self.pragmatic
                && matches!(
                    self.peek().kind,
                    TokenType::Some | TokenType::Most | TokenType::Many
                );
            // An optative wish ("May you prosper!") is a valid premise; the
            // standalone path tries it before the declarative sentence parser,
            // so the theorem-premise path must too (it self-backtracks to None
            // for non-optatives, falling through to `parse_sentence`).
            let mut premise_expr = match self.try_parse_optative()? {
                Some(opt) => opt,
                None => self.parse_sentence()?,
            };
            if scalar_trigger {
                if let Some(strengthened) = self.scalar_implicature(premise_expr) {
                    premise_expr = strengthened;
                }
            }
            premises.push(premise_expr);

            // Mark sentence boundary - this enables discourse mode and populates telescope
            // so pronouns in subsequent premises can resolve to referents from this premise
            self.world_state.end_sentence();

            // Consume the trailing terminator if present ("!" for
            // exclamative/optative/imperative premises).
            if self.check(&TokenType::Period) || self.check(&TokenType::Exclamation) {
                self.advance();
            }

            self.skip_whitespace_tokens();
        }

        // Parse goal (Prove: statement)
        let goal = if self.check(&TokenType::Prove) {
            self.advance(); // consume "Prove"

            if self.check(&TokenType::Colon) {
                self.advance();
            }

            self.skip_whitespace_tokens();

            // The goal may itself be an optative ("Prove: May you prosper!" —
            // identity through the wish encoding), same as the premise path.
            let goal_expr = match self.try_parse_optative()? {
                Some(opt) => opt,
                None => self.parse_sentence()?,
            };

            if self.check(&TokenType::Period) || self.check(&TokenType::Exclamation) {
                self.advance();
            }

            goal_expr
        } else {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "Prove".to_string() },
                span: self.current_span(),
            });
        };

        self.skip_whitespace_tokens();

        // Parse proof strategy (`Proof: Auto.` or `Proof: <tactic script>`). The word
        // `Proof` may lex as a real `Proof` block header OR — inline, after `Prove:` —
        // as an ordinary capitalized name; accept both so the `Proof:` line is found.
        let at_proof = self
            .check(&TokenType::BlockHeader { block_type: crate::token::BlockType::Proof })
            || self.tokens.get(self.current).is_some_and(|t| {
                self.interner.resolve(t.lexeme).eq_ignore_ascii_case("proof")
            });
        let strategy = if at_proof {
            self.advance();
            self.skip_whitespace_tokens();

            if self.check(&TokenType::Colon) {
                self.advance();
            }

            self.skip_whitespace_tokens();

            if self.check(&TokenType::Auto) {
                self.advance();
                ProofStrategy::Auto
            } else {
                // Anything else is an explicit tactic SCRIPT, written in the
                // English-esque vernacular: collect every token's lexeme up to the end
                // of the block (the next `##` header, a dedent, or EOF) and join them —
                // the tactic-script parser re-lexes the result, treating sentence
                // punctuation as step separators. So a prose proof flows straight in.
                let mut parts: Vec<String> = Vec::new();
                while !self.is_at_end()
                    && !matches!(self.tokens[self.current].kind, TokenType::BlockHeader { .. })
                    && !self.check(&TokenType::Dedent)
                {
                    let lexeme = self.tokens[self.current].lexeme;
                    parts.push(self.interner.resolve(lexeme).to_string());
                    self.advance();
                }
                let script = parts.join(" ");
                if script.trim().is_empty() {
                    ProofStrategy::Auto
                } else {
                    ProofStrategy::Script(script)
                }
            }
        } else {
            // No explicit proof strategy, default to Auto
            ProofStrategy::Auto
        };

        // Consume trailing period if present
        if self.check(&TokenType::Period) {
            self.advance();
        }

        let theorem = TheoremBlock {
            name,
            premises,
            premise_names,
            goal,
            strategy,
        };

        Ok(Stmt::Theorem(theorem))
    }

    /// Parse a `## Define` block (Rung 0a): a vernacular-logic predicate
    /// definition written as one biconditional sentence,
    /// `<subject> is <predicate> if and only if <definiens>`. The LHS predicate
    /// is the definiendum (its name + parameter symbols); the RHS is the
    /// definiens. A body that is not a top-level biconditional whose left side
    /// is a predicate application is a malformed definition and errors.
    fn parse_define_block(&mut self) -> ParseResult<Stmt<'a>> {
        use crate::ast::definition::DefinitionBlock;

        self.skip_whitespace_tokens();

        // Optional `: Label` after the header — the definiendum names itself, so
        // a label is decorative. Consume and ignore one if present.
        if self.check(&TokenType::Colon) {
            self.advance();
            self.skip_whitespace_tokens();
            if let Some(token) = self.tokens.get(self.current) {
                if matches!(
                    token.kind,
                    TokenType::Noun(_)
                        | TokenType::ProperName(_)
                        | TokenType::Adjective(_)
                        | TokenType::Verb { .. }
                ) {
                    self.advance();
                }
            }
            if self.check(&TokenType::Period) {
                self.advance();
            }
        }

        self.skip_whitespace_tokens();

        // The body is one biconditional sentence.
        let sentence = self.parse_sentence()?;
        if self.check(&TokenType::Period) || self.check(&TokenType::Exclamation) {
            self.advance();
        }

        // Split at the top-level biconditional.
        let (definiendum, definiens) = match sentence {
            LogicExpr::BinaryOp { left, op: TokenType::Iff, right } => (*left, *right),
            _ => {
                return Err(ParseError {
                    kind: ParseErrorKind::Custom(
                        "a `## Define` body must be a biconditional: \
                         `<subject> is <predicate> if and only if <definiens>`"
                            .to_string(),
                    ),
                    span: self.current_span(),
                });
            }
        };

        // The definiendum must be a predicate applied to its parameters; the
        // predicate name is the new concept, its arguments are the parameters.
        let (name, params) = match definiendum {
            LogicExpr::Predicate { name, args, .. } => {
                let pname = self.interner.resolve(*name).to_string();
                let params: Vec<Symbol> = args
                    .iter()
                    .filter_map(|t| match t {
                        Term::Constant(s) | Term::Variable(s) => Some(*s),
                        _ => None,
                    })
                    .collect();
                (pname, params)
            }
            _ => {
                return Err(ParseError {
                    kind: ParseErrorKind::Custom(
                        "the left side of a `## Define` biconditional must be a \
                         predicate applied to its parameters (e.g. `x is a bachelor`)"
                            .to_string(),
                    ),
                    span: self.current_span(),
                });
            }
        };

        Ok(Stmt::Definition(DefinitionBlock {
            name,
            params,
            definiendum,
            definiens,
        }))
    }

    /// Parse a `## Axiom` block: `## Axiom <name>: <formula>`. The leading identifier is
    /// the axiom's name; the remainder of the block is captured as formula text and parsed
    /// downstream by the formal-formula parser (`logicaffeine_proof::formula`). The body is
    /// formal first-order logic — `for all a b, Cong(a, b, b, a)` — which the NL parser
    /// cannot express, so it is kept as text rather than parsed here.
    fn parse_axiom_block(&mut self) -> ParseResult<Stmt<'a>> {
        use crate::ast::axiom::AxiomBlock;
        self.skip_whitespace_tokens();
        let name = self.read_block_name();
        self.skip_whitespace_tokens();
        if self.check(&TokenType::Colon) {
            self.advance();
        }
        let formula = self.collect_block_text();
        Ok(Stmt::Axiom(AxiomBlock { name, formula }))
    }

    /// Parse a `## Theory` block: `## Theory <name>` optionally followed by a development
    /// body (`Axiom …` / `Theorem …` declarations). The leading identifier is the theory's
    /// name; the remainder of the block is captured as development text, parsed downstream.
    fn parse_theory_block(&mut self) -> ParseResult<Stmt<'a>> {
        use crate::ast::axiom::TheoryBlock;
        self.skip_whitespace_tokens();
        let name = self.read_block_name();
        self.skip_whitespace_tokens();
        if self.check(&TokenType::Colon) {
            self.advance();
        }
        let body = self.collect_block_text();
        Ok(Stmt::Theory(TheoryBlock { name, body }))
    }

    /// Read a block's leading name token (a proper name / noun / adjective / verb lexeme),
    /// returning its text. `"Anonymous"` if no name token is present.
    fn read_block_name(&mut self) -> String {
        if let Some(token) = self.tokens.get(self.current) {
            if matches!(
                token.kind,
                TokenType::Noun(_)
                    | TokenType::ProperName(_)
                    | TokenType::Adjective(_)
                    | TokenType::Verb { .. }
            ) {
                let name = self.interner.resolve(token.lexeme).to_string();
                self.advance();
                return name;
            }
        }
        "Anonymous".to_string()
    }

    /// Collect the remaining tokens of the current block as text — each token's lexeme
    /// joined with spaces, up to the next `##` block header or EOF. Layout tokens
    /// (`Newline`/`Indent`/`Dedent`) are skipped rather than emitted, so a multi-line,
    /// indented development body flows through as clean whitespace-separated words for the
    /// downstream formal parser.
    fn collect_block_text(&mut self) -> String {
        let mut parts: Vec<String> = Vec::new();
        while !self.is_at_end()
            && !matches!(self.tokens[self.current].kind, TokenType::BlockHeader { .. })
        {
            match &self.tokens[self.current].kind {
                TokenType::Newline | TokenType::Indent | TokenType::Dedent => {}
                _ => {
                    let lexeme = self.tokens[self.current].lexeme;
                    parts.push(self.interner.resolve(lexeme).to_string());
                }
            }
            self.advance();
        }
        parts.join(" ")
    }

    /// Skip whitespace tokens (newlines, indentation)
    fn skip_whitespace_tokens(&mut self) {
        while self.check(&TokenType::Newline) || self.check(&TokenType::Indent) || self.check(&TokenType::Dedent) {
            self.advance();
        }
    }

    /// Insert each postcondition (`checks`) as a hard `RuntimeAssert` immediately
    /// before every `Return` reachable in `stmts`, recursing into the control-flow
    /// constructs whose returns EXIT the function (`If`/`While`/`Repeat`/`Inspect`/
    /// `Zone`). `Concurrent`/`Parallel` are intentionally left as leaves: their
    /// returns are swallowed (they don't exit the function), so a postcondition must
    /// NOT be inserted there. The fallthrough exit is handled by the caller.
    fn insert_ensures_before_returns(
        &self,
        stmts: &[Stmt<'a>],
        checks: &[&'a Expr<'a>],
    ) -> Vec<Stmt<'a>> {
        let mut out: Vec<Stmt<'a>> = Vec::new();
        for s in stmts {
            if matches!(s, Stmt::Return { .. }) {
                for &c in checks {
                    out.push(Stmt::RuntimeAssert { condition: c, hard: true });
                }
                out.push(s.clone());
                continue;
            }
            // Clone, then rewrite only the child blocks (via `..` patterns) — no need
            // to re-spell every field of every block-bearing variant.
            let mut c = s.clone();
            match &mut c {
                Stmt::If { then_block, else_block, .. } => {
                    *then_block = self.alloc_block(self.insert_ensures_before_returns(then_block, checks));
                    if let Some(eb) = else_block {
                        *eb = self.alloc_block(self.insert_ensures_before_returns(eb, checks));
                    }
                }
                Stmt::While { body, .. }
                | Stmt::Repeat { body, .. }
                | Stmt::Zone { body, .. } => {
                    *body = self.alloc_block(self.insert_ensures_before_returns(body, checks));
                }
                Stmt::Inspect { arms, .. } => {
                    for arm in arms.iter_mut() {
                        arm.body = self.alloc_block(self.insert_ensures_before_returns(arm.body, checks));
                    }
                }
                Stmt::Select { branches } => {
                    // A `Return` in a `select!` arm EXITS the function (unlike
                    // Concurrent/Parallel, whose returns are swallowed) — guard it too.
                    for br in branches.iter_mut() {
                        match br {
                            crate::ast::stmt::SelectBranch::Receive { body, .. }
                            | crate::ast::stmt::SelectBranch::Timeout { body, .. } => {
                                *body = self.alloc_block(self.insert_ensures_before_returns(body, checks));
                            }
                        }
                    }
                }
                // Concurrent/Parallel: their Returns are swallowed (don't exit the
                // function), so the postcondition must NOT be inserted there.
                _ => {}
            }
            out.push(c);
        }
        out
    }

    /// Allocate a freshly-built statement list in the imperative arena.
    fn alloc_block(&self, stmts: Vec<Stmt<'a>>) -> &'a [Stmt<'a>] {
        self.ctx.stmts.expect("imperative arenas not initialized").alloc_slice(stmts.into_iter())
    }

    /// Phase 32: Parse function definition after `## To` header
    /// Phase 32/38: Parse function definition
    /// Syntax: [To] [native] name (a: Type) [and (b: Type)] [-> ReturnType]
    ///         body statements... (only if not native)
    fn parse_function_def(&mut self) -> ParseResult<Stmt<'a>> {
        self.parse_function_def_with_flags(OptimizationConfig::all_on())
    }

    /// Parse function definition with optimization annotation flags.
    fn parse_function_def_with_flags(&mut self, opt_flags: OptimizationConfig) -> ParseResult<Stmt<'a>> {
        // Consume "To" if present (when called from parse_statement)
        if self.check(&TokenType::To) || self.check_preposition_is("to") {
            self.advance();
        }

        // Phase 38: Check for native modifier (prefix style: "## To native funcname ...")
        let mut is_native = if self.check(&TokenType::Native) {
            self.advance(); // consume "native"
            true
        } else {
            false
        };

        // Parse function name (first identifier after ## To [native])
        let name = self.expect_identifier()?;

        // Parse optional generic type parameters: "of [T]" or "of [T] and [U]"
        let mut parsed_generics: Vec<Symbol> = Vec::new();
        if self.check_preposition_is("of") {
            self.advance(); // consume "of"
            loop {
                if !self.check(&TokenType::LBracket) {
                    return Err(ParseError {
                        kind: ParseErrorKind::Custom("Expected '[TypeParam]' after 'of' in generic function".to_string()),
                        span: self.current_span(),
                    });
                }
                self.advance(); // consume [
                let type_param = self.expect_identifier()?;
                parsed_generics.push(type_param);
                if !self.check(&TokenType::RBracket) {
                    return Err(ParseError {
                        kind: ParseErrorKind::Custom("Expected ']' after type parameter name".to_string()),
                        span: self.current_span(),
                    });
                }
                self.advance(); // consume ]
                if self.check_word("and") {
                    self.advance(); // consume "and"
                } else {
                    break;
                }
            }
        }

        // Parse parameters: (name: Type) groups separated by "and", or comma-separated in one group
        let mut params = Vec::new();
        while self.check(&TokenType::LParen) {
            self.advance(); // consume (

            // Handle empty parameter list: ()
            if self.check(&TokenType::RParen) {
                self.advance(); // consume )
                break;
            }

            // Parse parameters in this group (possibly comma-separated)
            loop {
                let param_name = self.expect_identifier()?;

                // Expect colon
                if !self.check(&TokenType::Colon) {
                    return Err(ParseError {
                        kind: ParseErrorKind::ExpectedKeyword { keyword: ":".to_string() },
                        span: self.current_span(),
                    });
                }
                self.advance(); // consume :

                // MVS: a `mutable` parameter passes by reference (callee mutations
                // visible to caller) under value semantics — carried as a
                // `TypeExpr::Mutable` wrapper so the parameter tuple is unchanged.
                let param_is_mutable = self.check_mutable_keyword();
                if param_is_mutable {
                    self.advance(); // consume the `mutable`/`mut` keyword
                }

                // Phase 38: Parse full type expression instead of simple identifier
                let param_type_expr = self.parse_type_expression()?;
                let param_type_inner = self.ctx.alloc_type_expr(param_type_expr);
                let param_type = if param_is_mutable {
                    self.ctx.alloc_type_expr(TypeExpr::Mutable { inner: param_type_inner })
                } else {
                    param_type_inner
                };

                params.push((param_name, param_type));

                // Check for comma (more params in this group) or ) (end of group)
                if self.check(&TokenType::Comma) {
                    self.advance(); // consume ,
                    continue;
                }
                break;
            }

            // Expect )
            if !self.check(&TokenType::RParen) {
                return Err(ParseError {
                    kind: ParseErrorKind::ExpectedKeyword { keyword: ")".to_string() },
                    span: self.current_span(),
                });
            }
            self.advance(); // consume )

            // Check for "and", preposition, or "from" between parameter groups
            // Allows: "## To withdraw (amount: Int) from (balance: Int)"
            if self.check_word("and") || self.check_preposition() || self.check(&TokenType::From) {
                self.advance();
            }
        }

        // Phase 38: Parse optional return type -> Type
        let return_type = if self.check(&TokenType::Arrow) {
            self.advance(); // consume ->
            let ret_type_expr = self.parse_type_expression()?;
            Some(self.ctx.alloc_type_expr(ret_type_expr))
        } else {
            None
        };

        // FFI: Parse optional suffix modifiers: "is native <path>", "is exported [for <target>]"
        let mut native_path: Option<Symbol> = None;
        let mut is_exported = false;
        let mut export_target: Option<Symbol> = None;

        if self.check_word("is") {
            self.advance(); // consume "is"
            if self.check(&TokenType::Native) {
                // "is native" suffix style with required path string
                self.advance(); // consume "native"
                is_native = true;
                if let TokenType::StringLiteral(sym) = self.peek().kind {
                    native_path = Some(sym);
                    self.advance(); // consume the path string
                } else {
                    return Err(ParseError {
                        kind: ParseErrorKind::Custom(
                            "Expected a string literal for native function path (e.g., is native \"reqwest::blocking::get\")".to_string()
                        ),
                        span: self.current_span(),
                    });
                }
            } else if self.check_word("exported") {
                // "is exported [for <target>]"
                self.advance(); // consume "exported"
                is_exported = true;
                if self.check_word("for") {
                    self.advance(); // consume "for"
                    // "native" lexes as a keyword token, not an identifier.
                    let target_sym = if self.check(&TokenType::Native) {
                        self.advance();
                        self.interner.intern("native")
                    } else {
                        self.expect_identifier()?
                    };
                    let target_str = self.interner.resolve(target_sym);
                    if !target_str.eq_ignore_ascii_case("c")
                        && !target_str.eq_ignore_ascii_case("wasm")
                        && !target_str.eq_ignore_ascii_case("native")
                    {
                        return Err(ParseError {
                            kind: ParseErrorKind::Custom(
                                format!("Unsupported export target \"{}\". Supported targets are \"c\", \"wasm\", and \"native\".", target_str)
                            ),
                            span: self.current_span(),
                        });
                    }
                    export_target = Some(target_sym);
                }
            }
        }

        // Phase 38: Native functions have no body
        if is_native {
            // Consume trailing period or newline if present
            if self.check(&TokenType::Period) {
                self.advance();
            }
            if self.check(&TokenType::Newline) {
                self.advance();
            }

            // Return with empty body
            let empty_body = self.ctx.stmts.expect("imperative arenas not initialized")
                .alloc_slice(std::iter::empty());

            return Ok(Stmt::FunctionDef {
                name,
                generics: parsed_generics,
                params,
                body: empty_body,
                return_type,
                is_native: true,
                native_path,
                is_exported: false,
                export_target: None,
                opt_flags,
            });
        }

        // Non-native: expect colon after parameter list / return type
        if !self.check(&TokenType::Colon) {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: ":".to_string() },
                span: self.current_span(),
            });
        }
        self.advance(); // consume :

        // Expect indent for function body
        if !self.check(&TokenType::Indent) {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedStatement,
                span: self.current_span(),
            });
        }
        self.advance(); // consume Indent

        // Scope the `=`-mutation decision (and the infinity/nan literal guard)
        // to THIS function body: seed a fresh bound-set with the params, restore
        // the outer set on exit so a sibling function's or Main's `x = e` never
        // mistakes an out-of-scope `x` for a local (which would wrongly emit a
        // `Set` on an unbound name).
        let saved_user_bound = std::mem::take(&mut self.user_bound);
        for (param_name, _) in &params {
            self.user_bound.insert(*param_name);
        }

        // Parse body statements
        let mut body_stmts = Vec::new();
        // Contract clauses: `Requires <cond>.` (precondition, checked at entry) and
        // `Ensures <cond>.` (postcondition, checked before every return). Collected
        // here and desugared into enforced (hard) asserts below — NOT emitted as
        // ordinary statements.
        let mut requires_checks: Vec<&'a Expr<'a>> = Vec::new();
        let mut ensures_checks: Vec<&'a Expr<'a>> = Vec::new();
        while !self.check(&TokenType::Dedent) && !self.is_at_end() {
            // Skip newlines between statements
            if self.check(&TokenType::Newline) {
                self.advance();
                continue;
            }
            // Stop if we hit another block header
            if matches!(self.peek().kind, TokenType::BlockHeader { .. }) {
                break;
            }
            if self.check(&TokenType::Requires) {
                self.advance(); // consume "Requires"
                requires_checks.push(self.parse_condition()?);
                if self.check(&TokenType::Period) { self.advance(); }
                continue;
            }
            if self.check(&TokenType::Ensures) {
                self.advance(); // consume "Ensures"
                ensures_checks.push(self.parse_condition()?);
                if self.check(&TokenType::Period) { self.advance(); }
                continue;
            }
            let stmt = self.parse_statement()?;
            body_stmts.push(stmt);
            if self.check(&TokenType::Period) {
                self.advance();
            }
        }

        // Consume dedent if present
        if self.check(&TokenType::Dedent) {
            self.advance();
        }

        // Leave the function scope: the outer bound-set regains control.
        self.user_bound = saved_user_bound;

        // Desugar postconditions: a hard assert before EVERY return path (recursing
        // into nested control flow) and at fallthrough — so no exit escapes the check.
        if !ensures_checks.is_empty() {
            body_stmts = self.insert_ensures_before_returns(&body_stmts, &ensures_checks);
            if !matches!(body_stmts.last(), Some(Stmt::Return { .. })) {
                for &c in &ensures_checks {
                    body_stmts.push(Stmt::RuntimeAssert { condition: c, hard: true });
                }
            }
        }
        // Desugar preconditions: hard asserts at function entry.
        if !requires_checks.is_empty() {
            let mut prefixed: Vec<Stmt<'a>> = requires_checks
                .iter()
                .map(|&c| Stmt::RuntimeAssert { condition: c, hard: true })
                .collect();
            prefixed.extend(body_stmts);
            body_stmts = prefixed;
        }

        // Allocate body in arena
        let body = self.ctx.stmts.expect("imperative arenas not initialized")
            .alloc_slice(body_stmts.into_iter());

        Ok(Stmt::FunctionDef {
            name,
            generics: parsed_generics,
            params,
            body,
            return_type,
            is_native: false,
            native_path: None,
            is_exported,
            export_target,
            opt_flags,
        })
    }

    /// Parse a primary expression (literal, identifier, index, slice, list, etc.)
    /// Depth-guarded wrapper: primary expressions are the re-entry point of
    /// the imperative expression descent (`( expr )`, prefix forms), so a
    /// parenthesis tower recurses here once per level — the guard turns a
    /// would-be parser stack overflow into a graceful `AstTooDeep`.
    fn parse_primary_expr(&mut self) -> ParseResult<&'a Expr<'a>> {
        self.enter_recursion()?;
        let result = self.parse_primary_expr_inner();
        self.leave_recursion();
        result
    }

    fn parse_primary_expr_inner(&mut self) -> ParseResult<&'a Expr<'a>> {
        use crate::ast::{Expr, Literal};

        // English prefix arithmetic: `the sum/product/difference/quotient/remainder of A and B`
        // → the matching binary op. Unambiguous (the distinctive `the <op-noun> of` prefix), so it
        // never shadows a plain variable. `A`/`B` are full sub-expressions; the `and` delimiter is
        // consumed here (it binds tighter than the boolean `and`, which lives far above additive).
        if self.check_word("the") && self.peek_word_at(2, "of") {
            let op = if self.peek_word_at(1, "sum") {
                Some(BinaryOpKind::Add)
            } else if self.peek_word_at(1, "product") {
                Some(BinaryOpKind::Multiply)
            } else if self.peek_word_at(1, "difference") {
                Some(BinaryOpKind::Subtract)
            } else if self.peek_word_at(1, "quotient") {
                Some(BinaryOpKind::Divide)
            } else if self.peek_word_at(1, "remainder") {
                Some(BinaryOpKind::Modulo)
            } else {
                None
            };
            if let Some(op) = op {
                self.advance(); // "the"
                self.advance(); // op-noun
                self.advance(); // "of"
                let a = self.parse_additive_expr()?;
                if self.check(&TokenType::And) || self.check_word("and") {
                    self.advance(); // "and"
                } else {
                    return Err(ParseError {
                        kind: ParseErrorKind::ExpectedKeyword { keyword: "and".to_string() },
                        span: self.current_span(),
                    });
                }
                let b = self.parse_additive_expr()?;
                return Ok(self.ctx.alloc_imperative_expr(Expr::BinaryOp { op, left: a, right: b }));
            }
        }

        // Natural timestamp literal: `timestamp "2024-03-10T07:30:00Z"` → a Moment. Reads as a
        // value, not a function call; lowers to the (invisible) parse_timestamp. Only fires when an
        // identifier `timestamp` is immediately followed by a string, so a variable named
        // `timestamp` used on its own is unaffected.
        if matches!(self.peek().kind, TokenType::Identifier | TokenType::Noun(_))
            && self.interner.resolve(self.peek().lexeme).eq_ignore_ascii_case("timestamp")
        {
            let str_sym = match self.tokens.get(self.current + 1).map(|t| &t.kind) {
                Some(TokenType::StringLiteral(s)) => Some(*s),
                _ => None,
            };
            if let Some(s) = str_sym {
                self.advance(); // "timestamp"
                self.advance(); // the string
                let text = self.ctx.alloc_imperative_expr(Expr::Literal(Literal::Text(s)));
                let func = self.interner.intern("parse_timestamp");
                return Ok(self.ctx.alloc_imperative_expr(Expr::Call { function: func, args: vec![text] }));
            }
        }

        // Natural UUID literal: `uuid "550e8400-…"` → a Uuid (parses/normalizes the text). Reads as a
        // value; lowers to the invisible `uuid(text)` builtin. Only fires when the identifier `uuid`
        // is immediately followed by a string, so a variable named `uuid` is unaffected.
        if matches!(self.peek().kind, TokenType::Identifier | TokenType::Noun(_))
            && self.interner.resolve(self.peek().lexeme).eq_ignore_ascii_case("uuid")
        {
            let str_sym = match self.tokens.get(self.current + 1).map(|t| &t.kind) {
                Some(TokenType::StringLiteral(s)) => Some(*s),
                _ => None,
            };
            if let Some(s) = str_sym {
                self.advance(); // "uuid"
                self.advance(); // the string
                let text = self.ctx.alloc_imperative_expr(Expr::Literal(Literal::Text(s)));
                let func = self.interner.intern("uuid");
                return Ok(self.ctx.alloc_imperative_expr(Expr::Call { function: func, args: vec![text] }));
            }
        }

        let token = self.peek().clone();
        match &token.kind {
            // Phase 31: Constructor expression "new TypeName" or "a new TypeName"
            // Phase 33: Extended for variant constructors "new Circle with radius 10"
            // Phase 34: Extended for generic instantiation "new Box of Int"
            TokenType::New => {
                self.advance(); // consume "new"
                let base_type_name = self.expect_identifier()?;

                // Phase 36: Check for "from Module" qualification
                let type_name = if self.check(&TokenType::From) {
                    self.advance(); // consume "from"
                    let module_name = self.expect_identifier()?;
                    let module_str = self.interner.resolve(module_name);
                    let base_str = self.interner.resolve(base_type_name);
                    let qualified = format!("{}::{}", module_str, base_str);
                    self.interner.intern(&qualified)
                } else {
                    base_type_name
                };

                // Phase 33: Check if this is a variant constructor
                if let Some(enum_name) = self.find_variant(type_name) {
                    // Parse optional "with field value" pairs
                    let fields = if self.check_word("with") {
                        self.parse_variant_constructor_fields()?
                    } else {
                        vec![]
                    };
                    let base = self.ctx.alloc_imperative_expr(Expr::NewVariant {
                        enum_name,
                        variant: type_name,
                        fields,
                    });
                    return self.parse_field_access_chain(base);
                }

                // Phase 34: Parse generic type arguments "of Int" or "of Int and Text"
                let type_args = self.parse_generic_type_args(type_name)?;

                // Parse optional "with field value" pairs for struct initialization
                // But NOT "with capacity" — that's a pre-allocation hint handled by parse_let_statement
                let init_fields = if self.check_word("with") && !self.peek_word_at(1, "capacity") {
                    self.parse_struct_init_fields()?
                } else {
                    vec![]
                };

                let base = self.ctx.alloc_imperative_expr(Expr::New { type_name, type_args, init_fields });
                return self.parse_field_access_chain(base);
            }

            // Phase 31: Handle "a new TypeName" pattern OR single-letter identifier
            // Phase 33: Extended for variant constructors "a new Circle with radius 10"
            // Phase 34: Extended for generic instantiation "a new Box of Int"
            TokenType::Article(_) => {
                // Natural date-component accessor: `the year|month|day|weekday of <moment>` reads as
                // a sentence and desugars to the extractor (which threads through every tier). The
                // component words lex as CalendarUnit/Noun; we match by lexeme and require `of` next.
                let comp_lex = self.tokens.get(self.current + 1).map(|t| t.lexeme);
                let of_lex = self.tokens.get(self.current + 2).map(|t| t.lexeme);
                if let (Some(cl), Some(ol)) = (comp_lex, of_lex) {
                    let extractor = match self.interner.resolve(cl).to_ascii_lowercase().as_str() {
                        "year" => Some("year_of"),
                        "month" => Some("month_of"),
                        "day" => Some("day_of"),
                        "weekday" => Some("weekday_of"),
                        "hour" => Some("hour_of"),
                        "minute" => Some("minute_of"),
                        "second" => Some("second_of"),
                        "date" => Some("date_of"),
                        "time" => Some("time_of"),
                        "week" => Some("week_of"),
                        "quarter" => Some("quarter_of"),
                        _ => None,
                    };
                    if let Some(extractor) = extractor {
                        if self.interner.resolve(ol).eq_ignore_ascii_case("of") {
                            self.advance(); // "the"
                            self.advance(); // component noun
                            self.advance(); // "of"
                            let mut operand = self.parse_primary_expr()?;
                            // Zoned read: `the hour of m in "Asia/Tokyo"` → the LOCAL component. We
                            // intercept the `in "<zone>"` here (before it reaches the in_zone postfix,
                            // which would wrongly wrap the resulting Int) and shift the operand to the
                            // zone's local-as-UTC instant, so the SAME extractor yields the local field.
                            if self.check(&TokenType::In) || self.check_preposition_is("in") {
                                let zone_sym = match self.tokens.get(self.current + 1).map(|t| &t.kind) {
                                    Some(TokenType::StringLiteral(z)) => Some(*z),
                                    _ => None,
                                };
                                if let Some(z) = zone_sym {
                                    self.advance(); // "in"
                                    self.advance(); // the zone string
                                    let zone = self
                                        .ctx
                                        .alloc_imperative_expr(Expr::Literal(crate::ast::Literal::Text(z)));
                                    let local = self.interner.intern("local_instant");
                                    operand = self.ctx.alloc_imperative_expr(Expr::Call {
                                        function: local,
                                        args: vec![operand, zone],
                                    });
                                }
                            }
                            let func = self.interner.intern(extractor);
                            return Ok(self
                                .ctx
                                .alloc_imperative_expr(Expr::Call { function: func, args: vec![operand] }));
                        }
                    }
                    // Natural elapsed-time: `the <unit> between <a> and <b>`. FIXED-width units
                    // (second…week) divide the second-difference; CALENDAR units (month/year) count
                    // complete periods (a month is 28–31 days, so it cannot be a fixed division).
                    let unit_lexeme = self.interner.resolve(cl).to_ascii_lowercase();
                    let per_unit: Option<i64> = match unit_lexeme.as_str() {
                        "second" | "seconds" => Some(1),
                        "minute" | "minutes" => Some(60),
                        "hour" | "hours" => Some(3600),
                        "day" | "days" => Some(86400),
                        "week" | "weeks" => Some(604800),
                        _ => None,
                    };
                    let cal_func: Option<&str> = match unit_lexeme.as_str() {
                        "month" | "months" => Some("months_between"),
                        "year" | "years" => Some("years_between"),
                        _ => None,
                    };
                    if (per_unit.is_some() || cal_func.is_some())
                        && self.interner.resolve(ol).eq_ignore_ascii_case("between")
                    {
                        self.advance(); // "the"
                        self.advance(); // unit noun
                        self.advance(); // "between"
                        let a = self.parse_primary_expr()?;
                        if !(self.check(&TokenType::And) || self.check_word("and")) {
                            return Err(ParseError {
                                kind: ParseErrorKind::ExpectedKeyword { keyword: "and".to_string() },
                                span: self.current_span(),
                            });
                        }
                        self.advance(); // "and"
                        let b = self.parse_primary_expr()?;
                        if let Some(cal) = cal_func {
                            let func = self.interner.intern(cal);
                            return Ok(self
                                .ctx
                                .alloc_imperative_expr(Expr::Call { function: func, args: vec![a, b] }));
                        }
                        let per_unit = per_unit.unwrap();
                        let func = self.interner.intern("seconds_between");
                        let secs = self.ctx.alloc_imperative_expr(Expr::Call { function: func, args: vec![a, b] });
                        return Ok(if per_unit == 1 {
                            secs
                        } else {
                            let d = self.ctx.alloc_imperative_expr(Expr::Literal(Literal::Number(per_unit)));
                            self.ctx.alloc_imperative_expr(Expr::BinaryOp {
                                op: BinaryOpKind::Divide,
                                left: secs,
                                right: d,
                            })
                        });
                    }
                }
                // Phase 48: Check if followed by Manifest or Chunk token
                // Pattern: "the manifest of Zone" or "the chunk at N in Zone"
                if let Some(next) = self.tokens.get(self.current + 1) {
                    if matches!(next.kind, TokenType::Manifest) {
                        self.advance(); // consume "the"
                        // Delegate to Manifest handling
                        return self.parse_primary_expr();
                    }
                    if matches!(next.kind, TokenType::Chunk) {
                        self.advance(); // consume "the"
                        // Delegate to Chunk handling
                        return self.parse_primary_expr();
                    }
                    if matches!(next.kind, TokenType::Length) {
                        self.advance(); // consume "the"
                        return self.parse_primary_expr();
                    }
                }
                // Check if followed by New token
                if let Some(next) = self.tokens.get(self.current + 1) {
                    if matches!(next.kind, TokenType::New) {
                        self.advance(); // consume article "a"/"an"
                        self.advance(); // consume "new"
                        let base_type_name = self.expect_identifier()?;

                        // Phase 36: Check for "from Module" qualification
                        let type_name = if self.check(&TokenType::From) {
                            self.advance(); // consume "from"
                            let module_name = self.expect_identifier()?;
                            let module_str = self.interner.resolve(module_name);
                            let base_str = self.interner.resolve(base_type_name);
                            let qualified = format!("{}::{}", module_str, base_str);
                            self.interner.intern(&qualified)
                        } else {
                            base_type_name
                        };

                        // Phase 33: Check if this is a variant constructor
                        if let Some(enum_name) = self.find_variant(type_name) {
                            // Parse optional "with field value" pairs
                            let fields = if self.check_word("with") {
                                self.parse_variant_constructor_fields()?
                            } else {
                                vec![]
                            };
                            let base = self.ctx.alloc_imperative_expr(Expr::NewVariant {
                                enum_name,
                                variant: type_name,
                                fields,
                            });
                            return self.parse_field_access_chain(base);
                        }

                        // Phase 34: Parse generic type arguments "of Int" or "of Int and Text"
                        let type_args = self.parse_generic_type_args(type_name)?;

                        // Parse optional "with field value" pairs for struct initialization
                        // But NOT "with capacity" — that's a pre-allocation hint handled by parse_let_statement
                        let init_fields = if self.check_word("with") && !self.peek_word_at(1, "capacity") {
                            self.parse_struct_init_fields()?
                        } else {
                            vec![]
                        };

                        let base = self.ctx.alloc_imperative_expr(Expr::New { type_name, type_args, init_fields });
                        return self.parse_field_access_chain(base);
                    }
                }
                // Phase 32: Treat as identifier (single-letter var like "a", "b")
                let sym = token.lexeme;
                self.advance();
                let base = self.ctx.alloc_imperative_expr(Expr::Identifier(sym));
                return self.parse_field_access_chain(base);
            }

            // Index access: "item N of collection" or "item i of collection"
            TokenType::Item => {
                self.advance(); // consume "item"

                // Grand Challenge: Parse index as expression (number, identifier, or parenthesized)
                let index = if let TokenType::Number(sym) = &self.peek().kind {
                    // Literal numeral — 0 is guarded, floats are real keys.
                    let sym = *sym;
                    self.advance();
                    self.parse_index_numeral(sym)?
                } else if self.check(&TokenType::Minus)
                    && matches!(
                        self.tokens.get(self.current + 1).map(|t| &t.kind),
                        Some(TokenType::Number(_))
                    )
                {
                    // Negative index literal — end-relative (`item -1 of xs`
                    // is the last element).
                    self.advance(); // consume '-'
                    let TokenType::Number(sym) = self.peek().kind else { unreachable!() };
                    self.advance();
                    let num_str = self.interner.resolve(sym).to_string();
                    let n = self.parse_i64_numeral_signed(&num_str, true).map_err(|_| ParseError {
                        kind: ParseErrorKind::ExpectedKeyword {
                            keyword: format!("a numeric index (got '{}')", num_str),
                        },
                        span: self.current_span(),
                    })?;
                    self.ctx
                        .alloc_imperative_expr(Expr::Literal(crate::ast::Literal::Number(n)))
                } else if self.check(&TokenType::LParen) {
                    // Parenthesized expression like (mid + 1) — or a TUPLE
                    // key like ("a", 1) (tuples are content-keyed map keys).
                    self.advance(); // consume '('
                    let first = self.parse_imperative_expr()?;
                    let inner = if self.check(&TokenType::Comma) {
                        let mut items = vec![first];
                        while self.check(&TokenType::Comma) {
                            self.advance(); // consume ","
                            items.push(self.parse_imperative_expr()?);
                        }
                        self.ctx.alloc_imperative_expr(Expr::Tuple(items))
                    } else {
                        first
                    };
                    if !self.check(&TokenType::RParen) {
                        return Err(ParseError {
                            kind: ParseErrorKind::ExpectedKeyword { keyword: ")".to_string() },
                            span: self.current_span(),
                        });
                    }
                    self.advance(); // consume ')'
                    inner
                } else if let TokenType::StringLiteral(sym) = self.peek().kind {
                    // Phase 57B: String literal key for Map access like item "iron" of prices
                    let sym = sym;
                    self.advance();
                    self.ctx.alloc_imperative_expr(Expr::Literal(crate::ast::Literal::Text(sym)))
                } else if self.check(&TokenType::LBracket) {
                    // `item [1, 2] of m` — a List as a map key, rejected by
                    // design (a live List can mutate after insertion and the
                    // map would lose the entry). Name the key problem here;
                    // the generic missing-'of' error buries the lesson.
                    return Err(ParseError {
                        kind: ParseErrorKind::Custom(
                            "A List cannot be a map key: keys must be immutable, and a live \
                             List can change after insertion — the map would lose the entry. \
                             Which fixed value identifies this entry? Use an Int or Text key, \
                             or a tuple like ('a', 1) for a compound key."
                                .to_string(),
                        ),
                        span: self.peek().span,
                    });
                } else if !self.check_preposition_is("of") {
                    // Check for boolean literals before treating as variable
                    let word = self.interner.resolve(self.peek().lexeme);
                    if word == "true" {
                        self.advance();
                        self.ctx.alloc_imperative_expr(Expr::Literal(crate::ast::Literal::Boolean(true)))
                    } else if word == "false" {
                        self.advance();
                        self.ctx.alloc_imperative_expr(Expr::Literal(crate::ast::Literal::Boolean(false)))
                    } else {
                        // Variable identifier like i, j, idx (any token that's not "of")
                        let sym = self.peek().lexeme;
                        self.advance();
                        self.ctx.alloc_imperative_expr(Expr::Identifier(sym))
                    }
                } else {
                    return Err(ParseError {
                        kind: ParseErrorKind::ExpectedExpression,
                        span: self.current_span(),
                    });
                };

                // Expect "of"
                if !self.check_preposition_is("of") {
                    return Err(ParseError {
                        kind: ParseErrorKind::ExpectedKeyword { keyword: "of".to_string() },
                        span: self.current_span(),
                    });
                }
                self.advance(); // consume "of"

                // Parse collection as primary expression (identifier or field chain)
                // Using primary_expr instead of imperative_expr prevents consuming operators
                let collection = self.parse_primary_expr()?;

                Ok(self.ctx.alloc_imperative_expr(Expr::Index {
                    collection,
                    index,
                }))
            }

            // Slice access: "items N through M of collection"
            // OR variable named "items" - disambiguate by checking if next token starts an expression
            TokenType::Items => {
                // Peek ahead to determine if this is slice syntax or variable usage
                // Slice syntax: "items" followed by number or paren (clear indicators of index)
                // Variable: "items" followed by something else (operator, dot, etc.)
                let is_slice_syntax = if let Some(next) = self.tokens.get(self.current + 1) {
                    matches!(next.kind, TokenType::Number(_) | TokenType::LParen)
                } else {
                    false
                };

                if !is_slice_syntax {
                    // Treat "items" as a variable identifier
                    let sym = token.lexeme;
                    self.advance();
                    let base = self.ctx.alloc_imperative_expr(Expr::Identifier(sym));
                    return self.parse_field_access_chain(base);
                }

                self.advance(); // consume "items"

                // Grand Challenge: Parse start index as expression (number, identifier, or parenthesized)
                let start = if let TokenType::Number(sym) = &self.peek().kind {
                    // Literal number - check for zero index at compile time
                    let sym = *sym;
                    self.advance();
                    self.parse_index_numeral(sym)?
                } else if self.check(&TokenType::LParen) {
                    // Parenthesized expression like (mid + 1)
                    self.advance(); // consume '('
                    let inner = self.parse_imperative_expr()?;
                    if !self.check(&TokenType::RParen) {
                        return Err(ParseError {
                            kind: ParseErrorKind::ExpectedKeyword { keyword: ")".to_string() },
                            span: self.current_span(),
                        });
                    }
                    self.advance(); // consume ')'
                    inner
                } else if self.check(&TokenType::Length) {
                    // "length of X" compound expression as start index
                    self.advance(); // consume "length"
                    if self.check_preposition_is("of") {
                        self.advance(); // consume "of"
                        let target = self.parse_primary_expr()?;
                        self.ctx.alloc_imperative_expr(Expr::Length { collection: target })
                    } else {
                        // Bare "length" as identifier
                        let sym = self.tokens[self.current - 1].lexeme;
                        self.ctx.alloc_imperative_expr(Expr::Identifier(sym))
                    }
                } else if !self.check_preposition_is("through") {
                    // Variable identifier like mid, idx
                    let sym = self.peek().lexeme;
                    self.advance();
                    self.ctx.alloc_imperative_expr(Expr::Identifier(sym))
                } else {
                    return Err(ParseError {
                        kind: ParseErrorKind::ExpectedExpression,
                        span: self.current_span(),
                    });
                };

                // Expect "through"
                if !self.check_preposition_is("through") {
                    return Err(ParseError {
                        kind: ParseErrorKind::ExpectedKeyword { keyword: "through".to_string() },
                        span: self.current_span(),
                    });
                }
                self.advance(); // consume "through"

                // Grand Challenge: Parse end index as expression (number, identifier, or parenthesized)
                let end = if let TokenType::Number(sym) = &self.peek().kind {
                    // Literal number - check for zero index at compile time
                    let sym = *sym;
                    self.advance();
                    self.parse_index_numeral(sym)?
                } else if self.check(&TokenType::LParen) {
                    // Parenthesized expression like (mid + 1)
                    self.advance(); // consume '('
                    let inner = self.parse_imperative_expr()?;
                    if !self.check(&TokenType::RParen) {
                        return Err(ParseError {
                            kind: ParseErrorKind::ExpectedKeyword { keyword: ")".to_string() },
                            span: self.current_span(),
                        });
                    }
                    self.advance(); // consume ')'
                    inner
                } else if self.check(&TokenType::Length) {
                    // "length of X" compound expression as end index
                    self.advance(); // consume "length"
                    if self.check_preposition_is("of") {
                        self.advance(); // consume "of"
                        let target = self.parse_primary_expr()?;
                        self.ctx.alloc_imperative_expr(Expr::Length { collection: target })
                    } else {
                        // Bare "length" as identifier
                        let sym = self.tokens[self.current - 1].lexeme;
                        self.ctx.alloc_imperative_expr(Expr::Identifier(sym))
                    }
                } else if !self.check_preposition_is("of") {
                    // Variable identifier like n, mid
                    let sym = self.peek().lexeme;
                    self.advance();
                    self.ctx.alloc_imperative_expr(Expr::Identifier(sym))
                } else {
                    return Err(ParseError {
                        kind: ParseErrorKind::ExpectedExpression,
                        span: self.current_span(),
                    });
                };

                // "of collection" is now optional - collection can be inferred from context
                // (e.g., "items 1 through mid" when items is the local variable)
                let collection = if self.check_preposition_is("of") {
                    self.advance(); // consume "of"
                    self.parse_imperative_expr()?
                } else {
                    // The variable is the collection itself (already consumed as "items")
                    // Re-intern "items" to use as the collection identifier
                    let items_sym = self.interner.intern("items");
                    self.ctx.alloc_imperative_expr(Expr::Identifier(items_sym))
                };

                Ok(self.ctx.alloc_imperative_expr(Expr::Slice {
                    collection,
                    start,
                    end,
                }))
            }

            // List literal: [1, 2, 3]
            TokenType::LBracket => {
                self.advance(); // consume "["

                let mut items = Vec::new();
                if !self.check(&TokenType::RBracket) {
                    loop {
                        items.push(self.parse_imperative_expr()?);
                        if !self.check(&TokenType::Comma) {
                            break;
                        }
                        self.advance(); // consume ","
                        // A trailing comma (`[1, 2, 3,]`) ends the list.
                        if self.check(&TokenType::RBracket) {
                            break;
                        }
                    }
                }

                if !self.check(&TokenType::RBracket) {
                    return Err(ParseError {
                        kind: ParseErrorKind::ExpectedKeyword { keyword: "]".to_string() },
                        span: self.current_span(),
                    });
                }
                self.advance(); // consume "]"

                // Check for typed empty list: [] of Int
                if items.is_empty() && self.check_word("of") {
                    self.advance(); // consume "of"
                    let type_name = self.expect_identifier()?;
                    // Generate: Seq::<Type>::default()
                    let seq_sym = self.interner.intern("Seq");
                    return Ok(self.ctx.alloc_imperative_expr(Expr::New {
                        type_name: seq_sym,
                        type_args: vec![TypeExpr::Named(type_name)],
                        init_fields: vec![],
                    }));
                }

                Ok(self.ctx.alloc_imperative_expr(Expr::List(items)))
            }

            // `{k: v, …}` map literal / `{a, b, …}` set literal. A `:` after
            // the first element decides map-ness; the empty form requires an
            // element type exactly like `[] of Int` — `{} of Int` (set) /
            // `{} of Text to Int` (map). Non-empty literals lower to the
            // variadic `mapOf`/`setOf` builtins, so every engine shares one
            // construction path.
            TokenType::LBrace => {
                self.advance(); // consume "{"

                if self.check(&TokenType::RBrace) {
                    self.advance(); // consume "}"
                    if !self.check_word("of") {
                        return Err(ParseError {
                            kind: ParseErrorKind::ExpectedKeyword {
                                keyword: "of — an empty {} needs its element type: `{} of Int` (set) or `{} of Text to Int` (map)".to_string(),
                            },
                            span: self.current_span(),
                        });
                    }
                    self.advance(); // consume "of"
                    let first_ty = self.expect_identifier()?;
                    if self.check(&TokenType::To) || self.check_preposition_is("to") {
                        self.advance(); // consume "to"
                        let val_ty = self.expect_identifier()?;
                        let map_sym = self.interner.intern("Map");
                        return Ok(self.ctx.alloc_imperative_expr(Expr::New {
                            type_name: map_sym,
                            type_args: vec![TypeExpr::Named(first_ty), TypeExpr::Named(val_ty)],
                            init_fields: vec![],
                        }));
                    }
                    let set_sym = self.interner.intern("Set");
                    return Ok(self.ctx.alloc_imperative_expr(Expr::New {
                        type_name: set_sym,
                        type_args: vec![TypeExpr::Named(first_ty)],
                        init_fields: vec![],
                    }));
                }

                let first = self.parse_imperative_expr()?;
                if self.check(&TokenType::Colon) {
                    // Map literal: `{k: v, …}` → `mapOf(k, v, …)` (pairs flat,
                    // insertion order preserved by the ordered-map contract).
                    self.advance(); // consume ":"
                    let mut args = vec![first, self.parse_imperative_expr()?];
                    while self.check(&TokenType::Comma) {
                        self.advance(); // consume ","
                        // A trailing comma (`{a: 1, b: 2,}`) ends the map.
                        if self.check(&TokenType::RBrace) {
                            break;
                        }
                        args.push(self.parse_imperative_expr()?);
                        if !self.check(&TokenType::Colon) {
                            return Err(ParseError {
                                kind: ParseErrorKind::ExpectedKeyword { keyword: ":".to_string() },
                                span: self.current_span(),
                            });
                        }
                        self.advance(); // consume ":"
                        args.push(self.parse_imperative_expr()?);
                    }
                    if !self.check(&TokenType::RBrace) {
                        return Err(ParseError {
                            kind: ParseErrorKind::ExpectedKeyword { keyword: "}".to_string() },
                            span: self.current_span(),
                        });
                    }
                    self.advance(); // consume "}"
                    let map_of = self.interner.intern("mapOf");
                    return Ok(self.ctx.alloc_imperative_expr(Expr::Call { function: map_of, args }));
                }

                // Set literal: `{a, b, …}` → `setOf(a, b, …)`.
                let mut args = vec![first];
                while self.check(&TokenType::Comma) {
                    self.advance(); // consume ","
                    // A trailing comma (`{a, b, c,}`) ends the set.
                    if self.check(&TokenType::RBrace) {
                        break;
                    }
                    args.push(self.parse_imperative_expr()?);
                }
                if !self.check(&TokenType::RBrace) {
                    return Err(ParseError {
                        kind: ParseErrorKind::ExpectedKeyword { keyword: "}".to_string() },
                        span: self.current_span(),
                    });
                }
                self.advance(); // consume "}"
                let set_of = self.interner.intern("setOf");
                Ok(self.ctx.alloc_imperative_expr(Expr::Call { function: set_of, args }))
            }

            // Currency-symbol money literal (`$19.99`, `€5`, `¥100`) desugars to `money(num, "CODE")`,
            // the same shape as the spelled `19.99 USD` form. An exact (decimal) magnitude rides
            // `decimal(..)` so it never float-drifts; an integer magnitude passes through directly.
            TokenType::MoneyLiteral { amount, currency } => {
                let amount = *amount;
                let currency = *currency;
                let num_str = self.interner.resolve(amount).to_string();
                self.advance();
                let num_expr = if num_str.contains('.') {
                    let text = self.ctx.alloc_imperative_expr(Expr::Literal(Literal::Text(amount)));
                    let dec = self.interner.intern("decimal");
                    self.ctx.alloc_imperative_expr(Expr::Call { function: dec, args: vec![text] })
                } else {
                    let num = self.parse_i64_numeral(&num_str)?;
                    self.ctx.alloc_imperative_expr(Expr::Literal(Literal::Number(num)))
                };
                let code_expr = self.ctx.alloc_imperative_expr(Expr::Literal(Literal::Text(currency)));
                let func = self.interner.intern("money");
                return Ok(self
                    .ctx
                    .alloc_imperative_expr(Expr::Call { function: func, args: vec![num_expr, code_expr] }));
            }

            TokenType::Number(sym) => {
                let num_str = self.interner.resolve(*sym).to_string();
                self.advance();

                // Check if followed by CalendarUnit → Span literal
                if let TokenType::CalendarUnit(unit) = self.peek().kind {
                    return self.parse_span_literal_from_num(&num_str);
                }

                // Dimensioned quantity literal: a number immediately followed by a unit word
                // (`2 inches`, `5 kilograms`, `20 celsius`) desugars to `quantity(num, "unit")`.
                // Imperative-only (this path allocs imperative exprs), so natural-language phrases
                // like "ran 2 miles" — parsed by the clause grammar — are untouched. An exact
                // (decimal) magnitude rides the `decimal(..)` constructor so it never float-drifts.
                if matches!(
                    self.peek().kind,
                    TokenType::Identifier | TokenType::Noun(_) | TokenType::Adjective(_)
                ) {
                    let unit_lexeme = self.peek().lexeme;
                    let is_unit =
                        logicaffeine_base::quantity::units::by_name(self.interner.resolve(unit_lexeme)).is_some();
                    if is_unit {
                        self.advance(); // consume the unit word
                        let num_expr = if num_str.contains('.') || num_str.contains('e') || num_str.contains('E') {
                            let text = self.ctx.alloc_imperative_expr(Expr::Literal(Literal::Text(*sym)));
                            let dec = self.interner.intern("decimal");
                            self.ctx.alloc_imperative_expr(Expr::Call { function: dec, args: vec![text] })
                        } else {
                            let num = self.parse_i64_numeral(&num_str)?;
                            self.ctx.alloc_imperative_expr(Expr::Literal(Literal::Number(num)))
                        };
                        let unit_expr = self.ctx.alloc_imperative_expr(Expr::Literal(Literal::Text(unit_lexeme)));
                        let func = self.interner.intern("quantity");
                        return Ok(self
                            .ctx
                            .alloc_imperative_expr(Expr::Call { function: func, args: vec![num_expr, unit_expr] }));
                    }
                }

                // `19.99 USD` / `5 EUR` desugars to `money(num, "CODE")` — the same shape as the unit
                // sugar above, but the trailing token is an ISO-4217 currency code (checked AFTER
                // units so a unit word is never mis-read as money, and gated on `currency::by_code` so
                // only a real code triggers). An exact (decimal) amount rides `decimal(..)`.
                if matches!(
                    self.peek().kind,
                    TokenType::Identifier
                        | TokenType::Noun(_)
                        | TokenType::ProperName(_)
                        | TokenType::Adjective(_)
                ) {
                    let code_lexeme = self.peek().lexeme;
                    if logicaffeine_base::money::currency::by_code(self.interner.resolve(code_lexeme)).is_some() {
                        self.advance(); // consume the currency code
                        let num_expr = if num_str.contains('.') || num_str.contains('e') || num_str.contains('E') {
                            let text = self.ctx.alloc_imperative_expr(Expr::Literal(Literal::Text(*sym)));
                            let dec = self.interner.intern("decimal");
                            self.ctx.alloc_imperative_expr(Expr::Call { function: dec, args: vec![text] })
                        } else {
                            let num = self.parse_i64_numeral(&num_str)?;
                            self.ctx.alloc_imperative_expr(Expr::Literal(Literal::Number(num)))
                        };
                        let code_expr = self.ctx.alloc_imperative_expr(Expr::Literal(Literal::Text(code_lexeme)));
                        let func = self.interner.intern("money");
                        return Ok(self
                            .ctx
                            .alloc_imperative_expr(Expr::Call { function: func, args: vec![num_expr, code_expr] }));
                    }
                }

                // Radix first (`0x1E` has an `E` that is a hex digit, not
                // scientific notation); then the float sniff; both parse
                // EXACTLY or fail loudly — never a silent 0.
                if Self::is_radix_numeral(&num_str) {
                    let num = self.parse_i64_numeral(&num_str)?;
                    Ok(self.ctx.alloc_imperative_expr(Expr::Literal(Literal::Number(num))))
                } else if num_str.contains('.') || num_str.contains('e') || num_str.contains('E') {
                    let num = num_str.replace('_', "").parse::<f64>().map_err(|_| ParseError {
                        kind: ParseErrorKind::ExpectedKeyword {
                            keyword: format!("a Float literal (got `{}`)", num_str),
                        },
                        span: self.current_span(),
                    })?;
                    Ok(self.ctx.alloc_imperative_expr(Expr::Literal(Literal::Float(num))))
                } else {
                    let num = self.parse_i64_numeral(&num_str)?;
                    Ok(self.ctx.alloc_imperative_expr(Expr::Literal(Literal::Number(num))))
                }
            }

            // Phase 33: String literals
            TokenType::StringLiteral(sym) => {
                self.advance();
                Ok(self.ctx.alloc_imperative_expr(Expr::Literal(Literal::Text(*sym))))
            }

            // String interpolation: "Hello, {name}!"
            TokenType::InterpolatedString(sym) => {
                let raw = self.interner.resolve(*sym).to_string();
                self.advance();
                let parts = self.parse_interpolation_parts(&raw)?;
                Ok(self.ctx.alloc_imperative_expr(Expr::InterpolatedString(parts)))
            }

            // Character literals
            TokenType::CharLiteral(sym) => {
                let char_str = self.interner.resolve(*sym);
                let ch = char_str.chars().next().unwrap_or('\0');
                self.advance();
                Ok(self.ctx.alloc_imperative_expr(Expr::Literal(Literal::Char(ch))))
            }

            // Duration literals: 500ms, 2s, 50ns
            TokenType::DurationLiteral { nanos, .. } => {
                let nanos = *nanos;
                self.advance();
                Ok(self.ctx.alloc_imperative_expr(Expr::Literal(Literal::Duration(nanos))))
            }

            // Date literals: 2026-05-20
            // Also handles "DATE at TIME" → Moment
            TokenType::DateLiteral { days } => {
                let days = *days;
                self.advance();

                // Check for "at TIME" to create a Moment
                if self.check(&TokenType::At) {
                    self.advance(); // consume "at"

                    // Expect a TimeLiteral
                    if let TokenType::TimeLiteral { nanos_from_midnight } = self.peek().kind {
                        let time_nanos = nanos_from_midnight;
                        self.advance(); // consume time literal

                        // Convert to Moment: days * 86400 * 1e9 + time_nanos
                        let moment_nanos = (days as i64) * 86_400_000_000_000 + time_nanos;
                        return Ok(self.ctx.alloc_imperative_expr(Expr::Literal(Literal::Moment(moment_nanos))));
                    } else {
                        return Err(ParseError {
                            kind: ParseErrorKind::ExpectedExpression,
                            span: self.current_span(),
                        });
                    }
                }

                Ok(self.ctx.alloc_imperative_expr(Expr::Literal(Literal::Date(days))))
            }

            // Time-of-day literals: 4pm, 9:30am, noon, midnight
            TokenType::TimeLiteral { nanos_from_midnight } => {
                let nanos = *nanos_from_midnight;
                self.advance();
                Ok(self.ctx.alloc_imperative_expr(Expr::Literal(Literal::Time(nanos))))
            }

            // Handle 'nothing' literal
            TokenType::Nothing => {
                self.advance();
                Ok(self.ctx.alloc_imperative_expr(Expr::Literal(Literal::Nothing)))
            }

            // Option constructors: "some <expr>" → Some(expr), "none" → None
            TokenType::Some => {
                self.advance(); // consume "some"
                let value = self.parse_imperative_expr()?;
                Ok(self.ctx.alloc_imperative_expr(Expr::OptionSome { value }))
            }

            // Phase 43D: Length expression: "length of items" or "length(items)"
            TokenType::Length => {
                let func_name = self.peek().lexeme;

                // Check for function call syntax: length(x)
                if self.tokens.get(self.current + 1)
                    .map(|t| matches!(t.kind, TokenType::LParen))
                    .unwrap_or(false)
                {
                    self.advance(); // consume "length"
                    return self.parse_call_expr(func_name);
                }

                self.advance(); // consume "length"

                // Expect "of" for natural syntax
                if !self.check_preposition_is("of") {
                    return Err(ParseError {
                        kind: ParseErrorKind::ExpectedKeyword { keyword: "of".to_string() },
                        span: self.current_span(),
                    });
                }
                self.advance(); // consume "of"

                // Use parse_primary_expr so "length of arr / 2" binds as
                // "(length of arr) / 2" rather than "length of (arr / 2)"
                let collection = self.parse_primary_expr()?;
                Ok(self.ctx.alloc_imperative_expr(Expr::Length { collection }))
            }

            // Phase 43D: Copy expression: "copy of slice" or "copy(slice)"
            TokenType::Copy => {
                let func_name = self.peek().lexeme;

                // Check for function call syntax: copy(x)
                if self.tokens.get(self.current + 1)
                    .map(|t| matches!(t.kind, TokenType::LParen))
                    .unwrap_or(false)
                {
                    self.advance(); // consume "copy"
                    return self.parse_call_expr(func_name);
                }

                self.advance(); // consume "copy"

                // Expect "of" for natural syntax
                if !self.check_preposition_is("of") {
                    return Err(ParseError {
                        kind: ParseErrorKind::ExpectedKeyword { keyword: "of".to_string() },
                        span: self.current_span(),
                    });
                }
                self.advance(); // consume "of"

                let expr = self.parse_imperative_expr()?;
                Ok(self.ctx.alloc_imperative_expr(Expr::Copy { expr }))
            }

            // Phase 48: Manifest expression: "manifest of Zone"
            TokenType::Manifest => {
                self.advance(); // consume "manifest"

                // Expect "of"
                if !self.check_preposition_is("of") {
                    return Err(ParseError {
                        kind: ParseErrorKind::ExpectedKeyword { keyword: "of".to_string() },
                        span: self.current_span(),
                    });
                }
                self.advance(); // consume "of"

                let zone = self.parse_imperative_expr()?;
                Ok(self.ctx.alloc_imperative_expr(Expr::ManifestOf { zone }))
            }

            // Phase 48: Chunk expression: "chunk at N in Zone"
            TokenType::Chunk => {
                self.advance(); // consume "chunk"

                // Expect "at"
                if !self.check(&TokenType::At) {
                    return Err(ParseError {
                        kind: ParseErrorKind::ExpectedKeyword { keyword: "at".to_string() },
                        span: self.current_span(),
                    });
                }
                self.advance(); // consume "at"

                // The index is a dimensionless position, so it is parsed BELOW every construct that
                // consumes `in`: `parse_xor_expr`, not `parse_imperative_expr`/`parse_or_condition`.
                // The `in` here is the chunk construct's own keyword and must not be swallowed as an
                // `in "<zone>"` / `in <unit>` conversion (handled above `parse_or_condition`) nor as
                // Pythonic membership `<index> in <collection>` (handled in `parse_comparison`, which
                // `parse_or_condition` descends through).
                let index = self.parse_xor_expr()?;

                // Expect "in"
                if !self.check_preposition_is("in") && !self.check(&TokenType::In) {
                    return Err(ParseError {
                        kind: ParseErrorKind::ExpectedKeyword { keyword: "in".to_string() },
                        span: self.current_span(),
                    });
                }
                self.advance(); // consume "in"

                let zone = self.parse_imperative_expr()?;
                Ok(self.ctx.alloc_imperative_expr(Expr::ChunkAt { index, zone }))
            }

            // Handle verbs in expression context:
            // - "empty" is a literal Nothing
            // - Other verbs can be function names (e.g., read, write)
            TokenType::Verb { lemma, .. } => {
                let word = self.interner.resolve(*lemma).to_lowercase();
                if word == "empty" {
                    self.advance();
                    return Ok(self.ctx.alloc_imperative_expr(Expr::Literal(Literal::Nothing)));
                }
                // Phase 38: Allow verbs to be used as function calls
                let sym = token.lexeme;
                self.advance();
                if self.check(&TokenType::LParen) {
                    return self.parse_call_expr(sym);
                }
                // Treat as identifier reference
                self.verify_identifier_access(sym)?;
                let base = self.ctx.alloc_imperative_expr(Expr::Identifier(sym));
                self.parse_field_access_chain(base)
            }

            // Phase 38: Adverbs as identifiers (e.g., "now" for time functions)
            TokenType::TemporalAdverb(_) | TokenType::ScopalAdverb(_) | TokenType::Adverb(_) => {
                let sym = token.lexeme;
                self.advance();
                if self.check(&TokenType::LParen) {
                    return self.parse_call_expr(sym);
                }
                // Treat as identifier reference (e.g., "Let t be now.")
                self.verify_identifier_access(sym)?;
                let base = self.ctx.alloc_imperative_expr(Expr::Identifier(sym));
                self.parse_field_access_chain(base)
            }

            // Phase 10: IO keywords as function calls (e.g., "read", "write", "file")
            // Phase 57: Add/Remove keywords as function calls
            TokenType::Read | TokenType::Write | TokenType::File | TokenType::Console |
            TokenType::Add | TokenType::Remove => {
                let sym = token.lexeme;
                self.advance();
                if self.check(&TokenType::LParen) {
                    return self.parse_call_expr(sym);
                }
                // Treat as identifier reference
                self.verify_identifier_access(sym)?;
                let base = self.ctx.alloc_imperative_expr(Expr::Identifier(sym));
                self.parse_field_access_chain(base)
            }

            // Unified identifier handling - all identifier-like tokens get verified
            // First check for boolean/special literals before treating as variable
            TokenType::Noun(sym) | TokenType::ProperName(sym) | TokenType::Adjective(sym) => {
                let sym = *sym;
                let word = self.interner.resolve(sym);

                // Check for boolean literals
                if word == "true" {
                    self.advance();
                    return Ok(self.ctx.alloc_imperative_expr(Expr::Literal(Literal::Boolean(true))));
                }
                if word == "false" {
                    self.advance();
                    return Ok(self.ctx.alloc_imperative_expr(Expr::Literal(Literal::Boolean(false))));
                }
                // Float word literals (the `true`/`false` precedent): the
                // values every float tower needs a spelling for.
                if word == "infinity" && !self.user_bound.contains(&sym) {
                    self.advance();
                    return Ok(self.ctx.alloc_imperative_expr(Expr::Literal(Literal::Float(f64::INFINITY))));
                }
                if word == "nan" && !self.user_bound.contains(&sym) {
                    self.advance();
                    return Ok(self.ctx.alloc_imperative_expr(Expr::Literal(Literal::Float(f64::NAN))));
                }

                // Check for 'empty' - treat as unit value for collections
                if word == "empty" {
                    self.advance();
                    return Ok(self.ctx.alloc_imperative_expr(Expr::Literal(Literal::Nothing)));
                }

                // Option None literal: "none" → None
                if word == "none" {
                    self.advance();
                    return Ok(self.ctx.alloc_imperative_expr(Expr::OptionNone));
                }

                // Don't verify as variable - might be a function call or enum variant
                self.advance();

                // Phase 32: Check for function call: identifier(args)
                if self.check(&TokenType::LParen) {
                    return self.parse_call_expr(sym);
                }

                // Phase 33: Check if this is a bare enum variant (e.g., "North" for Direction)
                if let Some(enum_name) = self.find_variant(sym) {
                    let fields = if self.check_word("with") {
                        self.parse_variant_constructor_fields()?
                    } else {
                        vec![]
                    };
                    let base = self.ctx.alloc_imperative_expr(Expr::NewVariant {
                        enum_name,
                        variant: sym,
                        fields,
                    });
                    return self.parse_field_access_chain(base);
                }

                // Centralized verification for undefined/moved checks (only for variables)
                self.verify_identifier_access(sym)?;
                let base = self.ctx.alloc_imperative_expr(Expr::Identifier(sym));
                // Phase 31: Check for field access via possessive
                self.parse_field_access_chain(base)
            }

            // Pronouns can be variable names in code context ("i", "it")
            TokenType::Pronoun { .. } => {
                let sym = token.lexeme;
                self.advance();
                let base = self.ctx.alloc_imperative_expr(Expr::Identifier(sym));
                // Phase 31: Check for field access via possessive
                self.parse_field_access_chain(base)
            }

            // Phase 49: CRDT keywords can be function names (Merge, Increase)
            TokenType::Merge | TokenType::Increase => {
                let sym = token.lexeme;
                self.advance();

                // Check for function call: Merge(args)
                if self.check(&TokenType::LParen) {
                    return self.parse_call_expr(sym);
                }

                let base = self.ctx.alloc_imperative_expr(Expr::Identifier(sym));
                self.parse_field_access_chain(base)
            }

            // Escape hatch in expression position: `Escape to Rust:`
            // Lookahead: if followed by "to", parse as escape expression.
            // Otherwise, treat as identifier (variable named "escape").
            TokenType::Escape => {
                if self.tokens.get(self.current + 1).map_or(false, |t|
                    matches!(t.kind, TokenType::To) || {
                        if let TokenType::Preposition(sym) = t.kind {
                            sym.is(self.interner, "to")
                        } else {
                            false
                        }
                    }
                ) {
                    return self.parse_escape_expr();
                }
                // Fall through to identifier handling
                let sym = token.lexeme;
                self.advance();
                if self.check(&TokenType::LParen) {
                    return self.parse_call_expr(sym);
                }
                self.verify_identifier_access(sym)?;
                let base = self.ctx.alloc_imperative_expr(Expr::Identifier(sym));
                self.parse_field_access_chain(base)
            }

            // Keywords that can also be used as identifiers in expression context
            // These are contextual keywords - they have special meaning in specific positions
            // but can be used as variable names elsewhere
            TokenType::Values |    // "values" - can be a variable name
            TokenType::Both |      // correlative: "both X and Y"
            TokenType::Either |    // correlative: "either X or Y"
            TokenType::Combined |  // string concat: "combined with"
            TokenType::Followed |  // seq concat: "followed by" (also a valid variable name)
            TokenType::Shared |    // CRDT modifier
            TokenType::Particle(_) |  // phrasal verb particles: out, up, down, etc.
            TokenType::Preposition(_) |  // prepositions: from, into, etc.
            TokenType::All => {    // quantifier in FOL, but valid variable name in imperative code
                let sym = token.lexeme;
                self.advance();

                // Check for function call
                if self.check(&TokenType::LParen) {
                    return self.parse_call_expr(sym);
                }

                self.verify_identifier_access(sym)?;
                let base = self.ctx.alloc_imperative_expr(Expr::Identifier(sym));
                self.parse_field_access_chain(base)
            }

            // Handle ambiguous tokens that might be identifiers or function calls
            TokenType::Ambiguous { primary, alternatives } => {
                // Always use lexeme for identifier access - preserves original casing
                // (using verb lemma can give wrong casing like "Result" instead of "result")
                let sym = token.lexeme;

                // Check if this token can be used as identifier (has Noun/Verb/etc. interpretation)
                let is_identifier_token = match &**primary {
                    TokenType::Noun(_) | TokenType::Adjective(_) | TokenType::ProperName(_) |
                    TokenType::Verb { .. } => true,
                    _ => alternatives.iter().any(|t| matches!(t,
                        TokenType::Noun(_) | TokenType::Adjective(_) | TokenType::ProperName(_) |
                        TokenType::Verb { .. }
                    ))
                };

                if is_identifier_token {
                    self.advance();

                    // Check for function call: ambiguous_name(args)
                    if self.check(&TokenType::LParen) {
                        return self.parse_call_expr(sym);
                    }

                    self.verify_identifier_access(sym)?;
                    let base = self.ctx.alloc_imperative_expr(Expr::Identifier(sym));
                    // Phase 31: Check for field access via possessive
                    self.parse_field_access_chain(base)
                } else {
                    Err(ParseError {
                        kind: ParseErrorKind::ExpectedExpression,
                        span: self.current_span(),
                    })
                }
            }

            // Parenthesized expression, tuple literal, or closure
            TokenType::LParen => {
                // Try closure parse first using speculative parsing.
                // Closure syntax: `(name: Type, ...) -> expr` or `() -> expr`
                if let Some(closure) = self.try_parse(|p| p.parse_closure_expr()) {
                    return Ok(closure);
                }

                // Not a closure — parse as parenthesized expression or tuple
                self.advance(); // consume '('
                let first = self.parse_imperative_expr()?;

                // Check if this is a tuple (has comma) or just grouping
                if self.check(&TokenType::Comma) {
                    // It's a tuple - parse remaining elements
                    let mut items = vec![first];
                    while self.check(&TokenType::Comma) {
                        self.advance(); // consume ","
                        items.push(self.parse_imperative_expr()?);
                    }

                    if !self.check(&TokenType::RParen) {
                        return Err(ParseError {
                            kind: ParseErrorKind::ExpectedKeyword { keyword: ")".to_string() },
                            span: self.current_span(),
                        });
                    }
                    self.advance(); // consume ')'

                    let base = self.ctx.alloc_imperative_expr(Expr::Tuple(items));
                    self.parse_field_access_chain(base)
                } else {
                    // Just a parenthesized expression
                    if !self.check(&TokenType::RParen) {
                        return Err(ParseError {
                            kind: ParseErrorKind::ExpectedKeyword { keyword: ")".to_string() },
                            span: self.current_span(),
                        });
                    }
                    self.advance(); // consume ')'
                    // A parenthesized expression supports the same postfix chain
                    // as any primary: `(5).double()`, `(p).x`, `(xs)[1]`.
                    self.parse_field_access_chain(first)
                }
            }

            // "Call funcName with args" as an expression
            TokenType::Call => {
                self.advance(); // consume "Call"
                let function = match &self.peek().kind {
                    TokenType::Noun(sym) | TokenType::Adjective(sym) => {
                        let s = *sym;
                        self.advance();
                        s
                    }
                    TokenType::Verb { .. } | TokenType::Ambiguous { .. } => {
                        let s = self.peek().lexeme;
                        self.advance();
                        s
                    }
                    _ => {
                        return Err(ParseError {
                            kind: ParseErrorKind::ExpectedIdentifier,
                            span: self.current_span(),
                        });
                    }
                };
                let args = if self.check_preposition_is("with") {
                    self.advance(); // consume "with"
                    self.parse_call_arguments()?
                } else {
                    Vec::new()
                };
                Ok(self.ctx.alloc_imperative_expr(Expr::Call { function, args }))
            }

            _ => {
                Err(ParseError {
                    kind: ParseErrorKind::ExpectedExpression,
                    span: self.current_span(),
                })
            }
        }
    }

    /// Parse a closure expression: `(params) -> expr` or `(params) ->:` block.
    /// Called speculatively — will fail (and rollback) if not a closure.
    fn parse_closure_expr(&mut self) -> ParseResult<&'a Expr<'a>> {
        use crate::ast::stmt::ClosureBody;

        // Expect '('
        if !self.check(&TokenType::LParen) {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedExpression,
                span: self.current_span(),
            });
        }
        self.advance(); // consume '('

        // Parse parameter list
        let mut params = Vec::new();
        if !self.check(&TokenType::RParen) {
            // First parameter: name: Type
            let name = self.expect_identifier()?;
            if !self.check(&TokenType::Colon) {
                return Err(ParseError {
                    kind: ParseErrorKind::ExpectedKeyword { keyword: ":".to_string() },
                    span: self.current_span(),
                });
            }
            self.advance(); // consume ':'
            let ty = self.parse_type_expression()?;
            let ty_ref = self.ctx.alloc_type_expr(ty);
            params.push((name, ty_ref));

            // Additional parameters
            while self.check(&TokenType::Comma) {
                self.advance(); // consume ','
                let name = self.expect_identifier()?;
                if !self.check(&TokenType::Colon) {
                    return Err(ParseError {
                        kind: ParseErrorKind::ExpectedKeyword { keyword: ":".to_string() },
                        span: self.current_span(),
                    });
                }
                self.advance(); // consume ':'
                let ty = self.parse_type_expression()?;
                let ty_ref = self.ctx.alloc_type_expr(ty);
                params.push((name, ty_ref));
            }
        }

        // Expect ')'
        if !self.check(&TokenType::RParen) {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: ")".to_string() },
                span: self.current_span(),
            });
        }
        self.advance(); // consume ')'

        // Expect '->'
        if !self.check(&TokenType::Arrow) {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "->".to_string() },
                span: self.current_span(),
            });
        }
        self.advance(); // consume '->'

        // Check for block body (->:) vs expression body (-> expr)
        let body = if self.check(&TokenType::Colon) {
            self.advance(); // consume ':'
            // Parse indented block
            if !self.check(&TokenType::Indent) {
                return Err(ParseError {
                    kind: ParseErrorKind::ExpectedStatement,
                    span: self.current_span(),
                });
            }
            self.advance(); // consume Indent

            let mut block_stmts = Vec::new();
            while !self.check(&TokenType::Dedent) && !self.is_at_end() {
                let stmt = self.parse_statement()?;
                block_stmts.push(stmt);
                if self.check(&TokenType::Period) {
                    self.advance();
                }
            }
            if self.check(&TokenType::Dedent) {
                self.advance(); // consume Dedent
            }

            let block = self.ctx.stmts.expect("imperative arenas not initialized")
                .alloc_slice(block_stmts.into_iter());
            ClosureBody::Block(block)
        } else {
            // Single expression body — use parse_condition to support comparisons and boolean ops
            let expr = self.parse_condition()?;
            ClosureBody::Expression(expr)
        };

        Ok(self.ctx.alloc_imperative_expr(Expr::Closure {
            params,
            body,
            return_type: None,
        }))
    }

    /// Parse a complete imperative expression with full operator precedence.
    /// Delegates to parse_condition to support and/or/xor/shifts/comparisons
    /// in all expression contexts (Let, Set, function arguments, etc.).
    fn parse_imperative_expr(&mut self) -> ParseResult<&'a Expr<'a>> {
        self.parse_condition()
    }

    /// The bitwise chain, C precedence: `|` lowest, then `^`/`xor`, then
    /// `&`, all below comparison and above additive. On Sets the same
    /// operators are union / symmetric-difference / intersection.
    fn parse_xor_expr(&mut self) -> ParseResult<&'a Expr<'a>> {
        let mut left = self.parse_bitxor_expr()?;

        while self.check(&TokenType::VBar) {
            self.advance(); // consume "|"
            let right = self.parse_bitxor_expr()?;
            left = self.ctx.alloc_imperative_expr(Expr::BinaryOp {
                op: BinaryOpKind::BitOr,
                left,
                right,
            });
        }

        Ok(left)
    }

    /// `^` (or the word `xor`): bitwise XOR / set symmetric difference.
    fn parse_bitxor_expr(&mut self) -> ParseResult<&'a Expr<'a>> {
        let mut left = self.parse_bitand_expr()?;

        while self.check(&TokenType::Xor) || self.check(&TokenType::Caret) {
            self.advance(); // consume "xor" / "^"
            let right = self.parse_bitand_expr()?;
            left = self.ctx.alloc_imperative_expr(Expr::BinaryOp {
                op: BinaryOpKind::BitXor,
                left,
                right,
            });
        }

        Ok(left)
    }

    /// `&`: bitwise AND / set intersection.
    fn parse_bitand_expr(&mut self) -> ParseResult<&'a Expr<'a>> {
        let mut left = self.parse_additive_expr()?;

        while self.check(&TokenType::Amp) {
            self.advance(); // consume "&"
            let right = self.parse_additive_expr()?;
            left = self.ctx.alloc_imperative_expr(Expr::BinaryOp {
                op: BinaryOpKind::BitAnd,
                left,
                right,
            });
        }

        Ok(left)
    }

    /// Parse additive expressions (+, -, combined with, union, intersection, contains) - left-to-right associative
    fn parse_additive_expr(&mut self) -> ParseResult<&'a Expr<'a>> {
        let mut left = self.parse_shift_expr()?;

        loop {
            match &self.peek().kind {
                TokenType::Plus => {
                    self.advance();
                    let right = self.parse_shift_expr()?;
                    left = self.ctx.alloc_imperative_expr(Expr::BinaryOp {
                        op: BinaryOpKind::Add,
                        left,
                        right,
                    });
                }
                TokenType::Minus => {
                    self.advance();
                    let right = self.parse_shift_expr()?;
                    left = self.ctx.alloc_imperative_expr(Expr::BinaryOp {
                        op: BinaryOpKind::Subtract,
                        left,
                        right,
                    });
                }
                // Phase 53: "combined with" for string concatenation
                TokenType::Combined => {
                    self.advance(); // consume "combined"
                    // Expect "with" (preposition)
                    if !self.check_preposition_is("with") {
                        return Err(ParseError {
                            kind: ParseErrorKind::ExpectedKeyword { keyword: "with".to_string() },
                            span: self.current_span(),
                        });
                    }
                    self.advance(); // consume "with"
                    let right = self.parse_shift_expr()?;
                    left = self.ctx.alloc_imperative_expr(Expr::BinaryOp {
                        op: BinaryOpKind::Concat,
                        left,
                        right,
                    });
                }
                // "followed by" for sequence concatenation (merge two sequences into one)
                TokenType::Followed => {
                    self.advance(); // consume "followed"
                    if !self.check_preposition_is("by") {
                        return Err(ParseError {
                            kind: ParseErrorKind::ExpectedKeyword { keyword: "by".to_string() },
                            span: self.current_span(),
                        });
                    }
                    self.advance(); // consume "by"
                    let right = self.parse_shift_expr()?;
                    left = self.ctx.alloc_imperative_expr(Expr::BinaryOp {
                        op: BinaryOpKind::SeqConcat,
                        left,
                        right,
                    });
                }
                // Set operations: union, intersection
                TokenType::Union => {
                    self.advance(); // consume "union"
                    let right = self.parse_shift_expr()?;
                    left = self.ctx.alloc_imperative_expr(Expr::Union {
                        left,
                        right,
                    });
                }
                TokenType::Intersection => {
                    self.advance(); // consume "intersection"
                    let right = self.parse_shift_expr()?;
                    left = self.ctx.alloc_imperative_expr(Expr::Intersection {
                        left,
                        right,
                    });
                }
                // Set membership: "set contains value"
                TokenType::Contains => {
                    self.advance(); // consume "contains"
                    let value = self.parse_shift_expr()?;
                    left = self.ctx.alloc_imperative_expr(Expr::Contains {
                        collection: left,
                        value,
                    });
                }
                // `a without b` — the English set difference (`-` is the
                // symbolic spelling). Lowers to Subtract, which dispatches on
                // Set operands.
                _ if self.check_word("without") => {
                    self.advance(); // consume "without"
                    let right = self.parse_shift_expr()?;
                    left = self.ctx.alloc_imperative_expr(Expr::BinaryOp {
                        op: BinaryOpKind::Subtract,
                        left,
                        right,
                    });
                }
                // `n copies of x` — the English fill: a fresh sequence of n
                // deep-copied slots (`[x] * n` is the symbolic spelling).
                // Guarded on the following `of`, so a plain variable named
                // `copies` keeps resolving as an identifier.
                _ if self.check_word("copies") && self.peek_word_at(1, "of") => {
                    self.advance(); // consume "copies"
                    self.advance(); // consume "of"
                    let element = self.parse_shift_expr()?;
                    let repeat_sym = self.interner.intern("repeatSeq");
                    left = self.ctx.alloc_imperative_expr(Expr::Call {
                        function: repeat_sym,
                        args: vec![element, left],
                    });
                }
                // English infix `A plus B` / `A minus B` — the spoken spellings of `+`/`-`,
                // additive precedence. `check_op_word` yields to a same-named variable.
                _ if self.check_op_word("plus") => {
                    self.advance(); // consume "plus"
                    let right = self.parse_shift_expr()?;
                    left = self.ctx.alloc_imperative_expr(Expr::BinaryOp { op: BinaryOpKind::Add, left, right });
                }
                _ if self.check_op_word("minus") => {
                    self.advance(); // consume "minus"
                    let right = self.parse_shift_expr()?;
                    left = self.ctx.alloc_imperative_expr(Expr::BinaryOp { op: BinaryOpKind::Subtract, left, right });
                }
                _ => break,
            }
        }

        Ok(left)
    }

    /// Parse shift expressions: "x shifted left by y" / "x shifted right by y"
    /// Precedence: below additive, above multiplicative.
    fn parse_shift_expr(&mut self) -> ParseResult<&'a Expr<'a>> {
        let mut left = self.parse_multiplicative_expr()?;

        loop {
            if !self.check(&TokenType::Shifted) {
                break;
            }
            self.advance(); // consume "shifted"

            let is_left = self.check_word("left");
            if is_left {
                self.advance(); // consume "left"
            } else if self.check_word("right") {
                self.advance(); // consume "right"
            } else {
                return Err(ParseError {
                    kind: ParseErrorKind::ExpectedKeyword { keyword: "left or right".to_string() },
                    span: self.current_span(),
                });
            }

            // Expect "by"
            if !self.check_preposition_is("by") && !self.check_word("by") {
                return Err(ParseError {
                    kind: ParseErrorKind::ExpectedKeyword { keyword: "by".to_string() },
                    span: self.current_span(),
                });
            }
            self.advance(); // consume "by"

            let right = self.parse_multiplicative_expr()?;
            let op = if is_left { BinaryOpKind::Shl } else { BinaryOpKind::Shr };
            left = self.ctx.alloc_imperative_expr(Expr::BinaryOp { op, left, right });
        }

        Ok(left)
    }

    /// Parse unary expressions (currently just unary minus)
    fn parse_unary_expr(&mut self) -> ParseResult<&'a Expr<'a>> {
        use crate::ast::{Expr, Literal};

        if self.check(&TokenType::Tilde) {
            self.advance(); // consume "~"
            let operand = self.parse_unary_expr()?;
            // `~x` IS `x ^ -1` in two's complement — reuse the existing
            // BitXor path end to end (no new op anywhere downstream).
            let neg_one = self.ctx.alloc_imperative_expr(Expr::Literal(Literal::Number(-1)));
            return Ok(self.ctx.alloc_imperative_expr(Expr::BinaryOp {
                op: BinaryOpKind::BitXor,
                left: operand,
                right: neg_one,
            }));
        }
        if self.check(&TokenType::Minus) {
            // A negative LITERAL parses as one exact literal — the sign
            // attaches to the digits, so `-9223372036854775808` (i64::MIN,
            // whose magnitude alone overflows) and `-1.5` (a real Float
            // literal, not `0 - 1.5`) both come out exact.
            if let Some(TokenType::Number(sym)) =
                self.tokens.get(self.current + 1).map(|t| t.kind.clone())
            {
                self.advance(); // consume '-'
                self.advance(); // consume the numeral
                let num_str = self.interner.resolve(sym).to_string();
                if !Self::is_radix_numeral(&num_str)
                    && (num_str.contains('.') || num_str.contains('e') || num_str.contains('E'))
                {
                    let f = num_str.replace('_', "").parse::<f64>().map_err(|_| ParseError {
                        kind: ParseErrorKind::ExpectedKeyword {
                            keyword: format!("a Float literal (got `-{}`)", num_str),
                        },
                        span: self.current_span(),
                    })?;
                    return Ok(self.ctx.alloc_imperative_expr(Expr::Literal(Literal::Float(-f))));
                }
                let n = self.parse_i64_numeral_signed(&num_str, true)?;
                return Ok(self.ctx.alloc_imperative_expr(Expr::Literal(Literal::Number(n))));
            }
            if self
                .tokens
                .get(self.current + 1)
                .is_some_and(|t| self.interner.resolve(t.lexeme) == "infinity"
                    && !self.user_bound.contains(&t.lexeme))
            {
                self.advance(); // consume '-'
                self.advance(); // consume "infinity"
                return Ok(self
                    .ctx
                    .alloc_imperative_expr(Expr::Literal(Literal::Float(f64::NEG_INFINITY))));
            }
            self.advance(); // consume '-'
            let operand = self.parse_unary_expr()?; // recursive for --5
            // Implement as 0 - operand (no UnaryOp variant in Expr)
            return Ok(self.ctx.alloc_imperative_expr(Expr::BinaryOp {
                op: BinaryOpKind::Subtract,
                left: self.ctx.alloc_imperative_expr(Expr::Literal(Literal::Number(0))),
                right: operand,
            }));
        }
        self.parse_primary_expr()
    }

    /// Parse multiplicative expressions (*, /, %) - left-to-right associative
    /// Exponentiation  — binds tighter than , RIGHT-associative
    /// ( = ). The base is a unary expression; the exponent
    /// recurses into itself for right-associativity.
    fn parse_power_expr(&mut self) -> ParseResult<&'a Expr<'a>> {
        let base = self.parse_unary_expr()?;
        // `**` or the English spelling `A to the power of B` — both right-associative.
        let symbolic = self.check(&TokenType::StarStar);
        let spoken = (self.check_to_preposition() || self.check_word("to"))
            && self.peek_word_at(1, "the")
            && self.peek_word_at(2, "power")
            && self.peek_word_at(3, "of");
        if symbolic || spoken {
            if symbolic {
                self.advance(); // consume "**"
            } else {
                self.advance(); // "to"
                self.advance(); // "the"
                self.advance(); // "power"
                self.advance(); // "of"
            }
            let exp = self.parse_power_expr()?;
            return Ok(self.ctx.alloc_imperative_expr(Expr::BinaryOp {
                op: BinaryOpKind::Pow,
                left: base,
                right: exp,
            }));
        }
        Ok(base)
    }

    fn parse_multiplicative_expr(&mut self) -> ParseResult<&'a Expr<'a>> {
        let mut left = self.parse_power_expr()?;

        loop {
            let op = match &self.peek().kind {
                TokenType::Star => {
                    self.advance();
                    BinaryOpKind::Multiply
                }
                TokenType::Slash => {
                    self.advance();
                    BinaryOpKind::Divide
                }
                TokenType::SlashSlash => {
                    self.advance();
                    BinaryOpKind::FloorDivide
                }
                TokenType::Percent => {
                    self.advance();
                    BinaryOpKind::Modulo
                }
                // English infix `A times B`, `A divided by B`, `A modulo B` (`mod`) — the spoken
                // spellings of `*`/`/`/`%`, multiplicative precedence. `check_op_word` yields to a
                // same-named variable (declarer-wins).
                _ if self.check_op_word("times") => {
                    self.advance(); // consume "times"
                    BinaryOpKind::Multiply
                }
                _ if self.check_op_word("divided") && self.peek_word_at(1, "by") => {
                    self.advance(); // consume "divided"
                    self.advance(); // consume "by"
                    BinaryOpKind::Divide
                }
                _ if self.check_op_word("modulo") || self.check_op_word("mod") => {
                    self.advance(); // consume "modulo"/"mod"
                    BinaryOpKind::Modulo
                }
                _ => break,
            };
            let right = self.parse_power_expr()?;
            left = self.ctx.alloc_imperative_expr(Expr::BinaryOp {
                op,
                left,
                right,
            });
        }

        Ok(left)
    }

    /// Try to parse a binary operator (+, -, *, /)
    fn try_parse_binary_op(&mut self) -> Option<BinaryOpKind> {
        match &self.peek().kind {
            TokenType::Plus => {
                self.advance();
                Some(BinaryOpKind::Add)
            }
            TokenType::Minus => {
                self.advance();
                Some(BinaryOpKind::Subtract)
            }
            TokenType::Star => {
                self.advance();
                Some(BinaryOpKind::Multiply)
            }
            TokenType::Slash => {
                self.advance();
                Some(BinaryOpKind::Divide)
            }
            _ => None,
        }
    }

    /// Parse a Span literal starting from a number that was already consumed.
    /// Handles patterns like: "3 days", "2 months", "1 year and 3 days"
    /// Parse the contents of an interpolated string into a sequence of literal/expression parts.
    ///
    /// Input is the raw string content (without quotes), e.g., `Hello, {name}! Value: {x:.2}`
    /// `{{` and `}}` are escape sequences for literal braces.
    fn parse_interpolation_parts(&mut self, raw: &str) -> ParseResult<Vec<crate::ast::stmt::StringPart<'a>>> {
        use crate::ast::stmt::StringPart;

        let mut parts = Vec::new();
        let chars: Vec<char> = raw.chars().collect();
        let mut i = 0;
        let mut literal_buf = String::new();

        while i < chars.len() {
            match chars[i] {
                '{' if i + 1 < chars.len() && chars[i + 1] == '{' => {
                    // Escaped brace: {{ → literal {
                    literal_buf.push('{');
                    i += 2;
                }
                '{' => {
                    // Flush literal buffer
                    if !literal_buf.is_empty() {
                        let sym = self.interner.intern(&literal_buf);
                        parts.push(StringPart::Literal(sym));
                        literal_buf.clear();
                    }

                    // Find matching closing brace
                    let start = i + 1;
                    let mut depth = 1;
                    let mut j = start;
                    while j < chars.len() && depth > 0 {
                        if chars[j] == '{' { depth += 1; }
                        if chars[j] == '}' { depth -= 1; }
                        if depth > 0 { j += 1; }
                    }
                    if depth != 0 {
                        return Err(ParseError {
                            kind: crate::error::ParseErrorKind::Custom(
                                "Unclosed interpolation brace in string".to_string()
                            ),
                            span: self.current_span(),
                        });
                    }

                    let hole_content: String = chars[start..j].iter().collect();

                    // Detect debug format: {var=} or {var=:.2}
                    // Debug `=` is always the LAST `=` in the hole content.
                    // Using rfind ensures comparison operators like `==` don't trigger
                    // false positives — `{x == 5}` has no trailing `=` after an identifier.
                    let (hole_after_debug, is_debug) = {
                        if let Some(eq_pos) = hole_content.rfind('=') {
                            let before_eq = hole_content[..eq_pos].trim();
                            // Only treat as debug if the part before = is a simple identifier
                            // and the `=` is not part of `==`, `<=`, `>=`, `!=`
                            let is_double_eq = eq_pos > 0 && hole_content.as_bytes().get(eq_pos - 1) == Some(&b'=');
                            let is_preceded_by_comparison = eq_pos > 0 && matches!(hole_content.as_bytes().get(eq_pos - 1), Some(b'!' | b'<' | b'>'));
                            if !is_double_eq && !is_preceded_by_comparison
                                && !before_eq.is_empty()
                                && before_eq.chars().all(|c| c.is_alphanumeric() || c == '_')
                            {
                                (hole_content[..eq_pos].to_string() + &hole_content[eq_pos + 1..], true)
                            } else {
                                (hole_content.clone(), false)
                            }
                        } else {
                            (hole_content.clone(), false)
                        }
                    };

                    // Split on `:` for format specifier (but not `::`)
                    let (expr_str, format_spec) = if let Some(colon_pos) = hole_after_debug.rfind(':') {
                        let before = &hole_after_debug[..colon_pos];
                        let after = &hole_after_debug[colon_pos + 1..];
                        // Only treat as format spec if the part after `:` looks like a format spec
                        // (starts with `.`, `<`, `>`, `^`, `$`, or a digit, or is a known specifier letter)
                        if !after.is_empty() && (after.starts_with('.') || after.starts_with('<') || after.starts_with('>') || after.starts_with('^') || after == "$" || after.chars().next().map_or(false, |c| c.is_ascii_digit())) {
                            // Validate the format spec matches a known pattern
                            let valid = if after == "$" {
                                true
                            } else if after.starts_with('.') {
                                after[1..].parse::<usize>().is_ok()
                            } else if after.starts_with('<') || after.starts_with('>') || after.starts_with('^') {
                                after[1..].parse::<usize>().is_ok()
                            } else {
                                after.parse::<usize>().is_ok()
                            };
                            if !valid {
                                return Err(ParseError {
                                    kind: crate::error::ParseErrorKind::Custom(
                                        format!("Invalid format specifier `{}` in interpolation hole", after)
                                    ),
                                    span: self.current_span(),
                                });
                            }
                            (before.to_string(), Some(after.to_string()))
                        } else {
                            (hole_after_debug.clone(), None)
                        }
                    } else {
                        (hole_after_debug.clone(), None)
                    };

                    // Parse the expression through a sub-parser
                    let expr_source = expr_str.trim().to_string();
                    if expr_source.is_empty() {
                        return Err(ParseError {
                            kind: crate::error::ParseErrorKind::Custom(
                                "Empty interpolation hole in string".to_string()
                            ),
                            span: self.current_span(),
                        });
                    }

                    // Lex + parse the expression fragment by temporarily swapping
                    // the parser's token stream
                    let sub_expr = {
                        let mut sub_lexer = crate::lexer::Lexer::new(&expr_source, self.interner);
                        let sub_tokens = sub_lexer.tokenize();

                        // Save and swap parser state
                        let saved_tokens = std::mem::replace(&mut self.tokens, sub_tokens);
                        let saved_current = self.current;
                        self.current = 0;

                        let result = self.parse_primary_or_binary_expr();

                        // Restore parser state
                        self.tokens = saved_tokens;
                        self.current = saved_current;

                        result?
                    };

                    let format_sym = format_spec.map(|s| self.interner.intern(&s));
                    parts.push(StringPart::Expr {
                        value: sub_expr,
                        format_spec: format_sym,
                        debug: is_debug,
                    });

                    i = j + 1; // skip past closing '}'
                }
                '}' if i + 1 < chars.len() && chars[i + 1] == '}' => {
                    // Escaped brace: }} → literal }
                    literal_buf.push('}');
                    i += 2;
                }
                _ => {
                    literal_buf.push(chars[i]);
                    i += 1;
                }
            }
        }

        // Flush remaining literal
        if !literal_buf.is_empty() {
            let sym = self.interner.intern(&literal_buf);
            parts.push(StringPart::Literal(sym));
        }

        Ok(parts)
    }

    /// Parse a primary expression or a full binary expression for interpolation holes.
    fn parse_primary_or_binary_expr(&mut self) -> ParseResult<&'a Expr<'a>> {
        self.parse_imperative_expr()
    }

    fn parse_span_literal_from_num(&mut self, first_num_str: &str) -> ParseResult<&'a Expr<'a>> {
        use crate::ast::Literal;
        use crate::token::CalendarUnit;

        let first_num = self.parse_i64_numeral(first_num_str)?;

        // We expect a CalendarUnit after the number
        let unit = match self.peek().kind {
            TokenType::CalendarUnit(u) => u,
            _ => {
                return Err(ParseError {
                    kind: ParseErrorKind::ExpectedKeyword { keyword: "calendar unit (day, week, month, year)".to_string() },
                    span: self.current_span(),
                });
            }
        };
        self.advance(); // consume the CalendarUnit

        // Calendar fields (months/days) feed a `Span`; sub-day CLOCK units
        // (hour/minute/second) feed a nanosecond `Duration`. A literal built
        // purely from clock units IS a Duration — `After 5 seconds`,
        // `Sleep for 2 minutes`; a calendar (or mixed) literal stays a Span,
        // which models only months/days.
        let mut total_months: i64 = 0;
        let mut total_days: i64 = 0;
        let mut total_nanos: i64 = 0;
        let mut saw_calendar = false;
        let mut saw_clock = false;

        fn apply(
            unit: CalendarUnit,
            n: i64,
            months: &mut i64,
            days: &mut i64,
            nanos: &mut i64,
            cal: &mut bool,
            clk: &mut bool,
        ) {
            match unit {
                CalendarUnit::Day => {
                    *days += n;
                    *cal = true;
                }
                CalendarUnit::Week => {
                    *days += n * 7;
                    *cal = true;
                }
                CalendarUnit::Month => {
                    *months += n;
                    *cal = true;
                }
                CalendarUnit::Year => {
                    *months += n * 12;
                    *cal = true;
                }
                CalendarUnit::Hour => {
                    *nanos += n * 3_600_000_000_000;
                    *clk = true;
                }
                CalendarUnit::Minute => {
                    *nanos += n * 60_000_000_000;
                    *clk = true;
                }
                CalendarUnit::Second => {
                    *nanos += n * 1_000_000_000;
                    *clk = true;
                }
            }
        }
        apply(
            unit, first_num, &mut total_months, &mut total_days, &mut total_nanos,
            &mut saw_calendar, &mut saw_clock,
        );

        // Check for "and" followed by more Number + CalendarUnit
        while self.check(&TokenType::And) {
            self.advance(); // consume "and"

            // Expect another Number
            let next_num = match &self.peek().kind {
                TokenType::Number(sym) => {
                    let num_str = self.interner.resolve(*sym).to_string();
                    self.advance();
                    self.parse_i64_numeral(&num_str)?
                }
                _ => break, // Not a number, backtrack is complex so just stop
            };

            // Expect another CalendarUnit
            let next_unit = match self.peek().kind {
                TokenType::CalendarUnit(u) => {
                    self.advance();
                    u
                }
                _ => break, // Not a unit, backtrack is complex so just stop
            };

            apply(
                next_unit, next_num, &mut total_months, &mut total_days, &mut total_nanos,
                &mut saw_calendar, &mut saw_clock,
            );
        }

        if saw_clock && !saw_calendar {
            Ok(self.ctx.alloc_imperative_expr(Expr::Literal(Literal::Duration(total_nanos))))
        } else {
            Ok(self.ctx.alloc_imperative_expr(Expr::Literal(Literal::Span {
                months: total_months as i32,
                days: total_days as i32,
            })))
        }
    }

    /// Phase 32: Parse function call expression: f(x, y, ...)
    fn parse_call_expr(&mut self, function: Symbol) -> ParseResult<&'a Expr<'a>> {
        use crate::ast::Expr;

        self.advance(); // consume '('

        let mut args = Vec::new();
        if !self.check(&TokenType::RParen) {
            loop {
                args.push(self.parse_imperative_expr()?);
                if !self.check(&TokenType::Comma) {
                    break;
                }
                self.advance(); // consume ','
            }
        }

        if !self.check(&TokenType::RParen) {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: ")".to_string() },
                span: self.current_span(),
            });
        }
        self.advance(); // consume ')'

        Ok(self.ctx.alloc_imperative_expr(Expr::Call { function, args }))
    }

    /// Phase 31: Parse field access chain via possessive ('s) and bracket indexing
    /// Handles patterns like: p's x, p's x's y, items[1], items[i]'s field
    fn parse_field_access_chain(&mut self, base: &'a Expr<'a>) -> ParseResult<&'a Expr<'a>> {
        use crate::ast::Expr;

        let mut result = base;

        // Keep parsing field accesses and bracket indexing
        loop {
            if self.check(&TokenType::Dot) {
                // The dot: `p.x` field access (≡ `p's x`) or `xs.f(a)` UFCS
                // method syntax (≡ `f(xs, a)` — the RECEIVER becomes the first
                // argument, so every method spelling lowers to a plain call and
                // all engines get it free).
                self.advance(); // consume "."
                let name = self.expect_identifier()?;
                if self.check(&TokenType::LParen) {
                    self.advance(); // consume "("
                    let mut args = vec![result]; // receiver first
                    if !self.check(&TokenType::RParen) {
                        loop {
                            args.push(self.parse_imperative_expr()?);
                            if !self.check(&TokenType::Comma) {
                                break;
                            }
                            self.advance(); // consume ","
                        }
                    }
                    if !self.check(&TokenType::RParen) {
                        return Err(ParseError {
                            kind: ParseErrorKind::ExpectedKeyword { keyword: ")".to_string() },
                            span: self.current_span(),
                        });
                    }
                    self.advance(); // consume ")"
                    result = self.ctx.alloc_imperative_expr(Expr::Call { function: name, args });
                } else {
                    result = self.ctx.alloc_imperative_expr(Expr::FieldAccess {
                        object: result,
                        field: name,
                    });
                }
            } else if self.check(&TokenType::Possessive) {
                // Field access: p's x
                self.advance(); // consume "'s"
                let field = self.expect_identifier()?;
                result = self.ctx.alloc_imperative_expr(Expr::FieldAccess {
                    object: result,
                    field,
                });
            } else if self.check(&TokenType::LBracket) {
                // Bracket indexing: items[1], items[i]
                self.advance(); // consume "["
                let index = self.parse_imperative_expr()?;

                if !self.check(&TokenType::RBracket) {
                    return Err(ParseError {
                        kind: ParseErrorKind::ExpectedKeyword { keyword: "]".to_string() },
                        span: self.current_span(),
                    });
                }
                self.advance(); // consume "]"

                result = self.ctx.alloc_imperative_expr(Expr::Index {
                    collection: result,
                    index,
                });
            } else {
                break;
            }
        }

        Ok(result)
    }

    /// Centralized verification for identifier access in imperative mode.
    /// Checks for use-after-move errors on known variables.
    fn verify_identifier_access(&self, sym: Symbol) -> ParseResult<()> {
        if self.mode != ParserMode::Imperative {
            return Ok(());
        }

        // Check if variable has been moved
        if let Some(crate::drs::OwnershipState::Moved) = self.world_state.get_ownership_by_var(sym) {
            return Err(ParseError {
                kind: ParseErrorKind::UseAfterMove {
                    name: self.interner.resolve(sym).to_string()
                },
                span: self.current_span(),
            });
        }

        Ok(())
    }

    fn expect_identifier(&mut self) -> ParseResult<Symbol> {
        let token = self.peek().clone();
        match &token.kind {
            // Standard identifiers
            TokenType::Noun(sym) | TokenType::ProperName(sym) | TokenType::Adjective(sym) => {
                self.advance();
                Ok(*sym)
            }
            // Verbs can be variable names in code context ("empty", "run", etc.)
            // Use raw lexeme to preserve original casing
            TokenType::Verb { .. } => {
                let sym = token.lexeme;
                self.advance();
                Ok(sym)
            }
            // Phase 32: Articles can be single-letter identifiers (a, an)
            TokenType::Article(_) => {
                let sym = token.lexeme;
                self.advance();
                Ok(sym)
            }
            // Overloaded tokens that are valid identifiers in code context
            TokenType::Pronoun { .. } |  // "i", "it"
            TokenType::Items |           // "items"
            TokenType::Values |          // "values"
            TokenType::Item |            // "item"
            TokenType::Nothing |         // "nothing"
            // Phase 38: Adverbs can be function names (now, sleep, etc.)
            TokenType::TemporalAdverb(_) |
            TokenType::ScopalAdverb(_) |
            TokenType::Adverb(_) |
            // Phase 10: IO keywords can be function names (read, write, file, console)
            TokenType::Read |
            TokenType::Write |
            TokenType::File |
            TokenType::Console |
            // Phase 49: CRDT keywords can be type/function names
            TokenType::Merge |
            TokenType::Increase |
            TokenType::Decrease |
            // Phase 51: "sleep" leads the Sleep statement but also names a native
            // (`## To native sleep`) — in name position the declarer wins.
            TokenType::Sleep |
            // Phase 49b: CRDT type keywords can be type names
            TokenType::Tally |
            TokenType::SharedSet |
            TokenType::SharedSequence |
            TokenType::CollaborativeSequence |
            // Phase 54: "first", "second", etc. can be variable names
            // Phase 57: "add", "remove" can be function names
            TokenType::Add |
            TokenType::Remove |
            TokenType::First |
            // Correlative conjunctions and other keywords usable as identifiers
            TokenType::Both |            // "both" (correlative: both X and Y)
            TokenType::Either |          // "either" (correlative: either X or Y)
            TokenType::Combined |        // "combined" (string concat: combined with)
            TokenType::Followed |        // "followed" (seq concat: followed by; also a variable name)
            TokenType::Shared |          // "shared" (CRDT type modifier)
            TokenType::All |             // "all" (FOL quantifier, valid variable name in imperative)
            // Calendar units can be type/variable names (Day, Week, Month, Year)
            TokenType::CalendarUnit(_) |
            // Phase 103: Focus particles can be variant names (Just, Only, Even)
            TokenType::Focus(_) |
            // Phrasal verb particles can be variable names (out, up, down, etc.)
            TokenType::Particle(_) |
            // Prepositions can be variable names in code context (from, into, etc.)
            TokenType::Preposition(_) |
            // Escape hatch keyword can be a variable name
            TokenType::Escape => {
                // Use the raw lexeme (interned string) as the symbol
                let sym = token.lexeme;
                self.advance();
                Ok(sym)
            }
            TokenType::Ambiguous { .. } => {
                // For ambiguous tokens, always use the raw lexeme to preserve original casing
                // (using verb lemma can give wrong casing like "State" instead of "state")
                let sym = token.lexeme;
                self.advance();
                Ok(sym)
            }
            _ => Err(ParseError {
                kind: ParseErrorKind::ExpectedIdentifier,
                span: self.current_span(),
            }),
        }
    }

    fn consume_content_word_for_relative(&mut self) -> ParseResult<Symbol> {
        let t = self.advance().clone();
        match t.kind {
            TokenType::Noun(s) | TokenType::Adjective(s) => Ok(s),
            TokenType::ProperName(s) => Ok(s),
            TokenType::Verb { lemma, .. } => Ok(lemma),
            other => Err(ParseError {
                kind: ParseErrorKind::ExpectedContentWord { found: other },
                span: self.current_span(),
            }),
        }
    }

    fn check_modal(&self) -> bool {
        matches!(
            self.peek().kind,
            TokenType::Must
                | TokenType::Shall
                | TokenType::Should
                | TokenType::Can
                | TokenType::May
                | TokenType::Cannot
                | TokenType::Could
                | TokenType::Would
                | TokenType::Might
        )
    }

    /// Does an NP head follow the current (possessive) token — i.e. zero or
    /// more adjectives ending in a noun? "his dog" / "her red dog" yes;
    /// "its wet" (the it's typo) no.
    fn possessive_np_head_follows(&self) -> bool {
        let mut i = self.current + 1;
        while let Some(token) = self.tokens.get(i) {
            match &token.kind {
                TokenType::Adjective(_) => i += 1,
                TokenType::Noun(_) => return true,
                // A noun READING suffices ("its value" — "value" lexes
                // Ambiguous{Verb|Noun}); the NP parse commits it to noun.
                TokenType::Ambiguous { primary, alternatives } => {
                    return matches!(**primary, TokenType::Noun(_))
                        || alternatives.iter().any(|t| matches!(t, TokenType::Noun(_)));
                }
                _ => return false,
            }
        }
        false
    }

    fn check_pronoun(&self) -> bool {
        match &self.peek().kind {
            TokenType::Pronoun { case, .. } => {
                if matches!(case, Case::Possessive) {
                    // In noun_priority_mode, possessive pronouns start NPs,
                    // not standalone objects.
                    if self.noun_priority_mode {
                        return false;
                    }
                    // A possessive followed by an NP head ("his dog",
                    // "her red dog") is a possessive NP, never a standalone
                    // pronoun. A possessive followed by a bare adjective
                    // ("its wet") stays on the pronoun path so the it's-typo
                    // grammar error still fires.
                    if self.possessive_np_head_follows() {
                        return false;
                    }
                }
                true
            }
            TokenType::Ambiguous { primary, alternatives } => {
                let has_possessive = matches!(**primary, TokenType::Pronoun { case: Case::Possessive, .. })
                    || alternatives.iter().any(|t| matches!(t, TokenType::Pronoun { case: Case::Possessive, .. }));
                // In noun_priority_mode, if there's a possessive alternative, prefer noun path
                if self.noun_priority_mode && has_possessive {
                    return false;
                }
                // An object/possessive-ambiguous pronoun ("her") stands alone
                // only when no NP head follows: "Mary saw her." is a pronoun
                // object, "Mary saw her dog." is a possessive NP.
                if has_possessive && self.possessive_np_head_follows() {
                    return false;
                }
                matches!(**primary, TokenType::Pronoun { .. })
                    || alternatives.iter().any(|t| matches!(t, TokenType::Pronoun { .. }))
            }
            _ => false,
        }
    }

    /// True when the cursor heads a REDUCED-RELATIVE participle — a non-auxiliary
    /// verb, optionally behind a single leading ordinal/temporal adverb ("FIRST
    /// climbed", "originally seen"). The list-subject gate uses it so a first member
    /// carrying a reduced relative ("The peak CLIMBED in 1845, the dog, and Mt. Quinn
    /// are three different mountains") routes into the list parser, which consumes
    /// the reduced relative per member via `try_consume_reduced_relative`.
    fn peek_heads_reduced_relative_participle(&self) -> bool {
        let idx = if matches!(
            self.peek().kind,
            TokenType::Adverb(_) | TokenType::TemporalAdverb(_)
        ) && self
            .tokens
            .get(self.current + 1)
            .map_or(false, |t| self.kind_is_verb(&t.kind))
        {
            self.current + 1
        } else {
            self.current
        };
        let Some(t) = self.tokens.get(idx) else {
            return false;
        };
        if !self.kind_is_verb(&t.kind) {
            return false;
        }
        // A perfect/passive/do auxiliary heads a finite matrix VP, not a reduced
        // relative ("The apple HAS been eaten").
        if let TokenType::Verb { lemma, .. } = &t.kind {
            return !matches!(
                self.interner.resolve(*lemma).to_lowercase().as_str(),
                "have" | "be" | "do"
            );
        }
        true
    }

    /// True when a comma appears before the end of the current clause (the next
    /// Period/EOF). The list-subject gate requires one before speculating on a
    /// reduced-relative first member — an enumerated list ("A, B, and C are …")
    /// always has a comma, an ordinary main clause does not.
    fn has_comma_before_clause_end(&self) -> bool {
        for i in self.current..self.tokens.len() {
            match &self.tokens[i].kind {
                TokenType::Period | TokenType::EOF => return false,
                TokenType::Comma => return true,
                _ => {}
            }
        }
        false
    }

    /// Consume a post-nominal REDUCED RELATIVE — an optional leading ordinal/temporal
    /// adverb ("first"), a past/-ing participle ("climbed", "seen", "going"), and its
    /// PP / measure / directional-"to" complements ("in 1845", "by Captain Norris",
    /// "to Pete's") — as restriction predicates over `term`. Returns their conjunction,
    /// or None when no participle heads the cursor.
    ///
    /// `parse_noun_phrase` attaches reduced relatives only when the participle is
    /// unambiguous; its conservative, matrix-verb-gated post-subject handler keeps
    /// "The team won in 1989" a main clause. In a NOMINAL COORDINATION position — a
    /// list member, an either/or disjunct, an of-pair member — the NP cannot be a
    /// main-clause subject, so a participle there IS a reduced relative. This helper
    /// attaches it so the member's restrictor survives, shared so every coordination
    /// site composes once. Callers gate it to those positions (the participle here is
    /// committed unconditionally, no matrix-verb lookahead).
    fn try_consume_reduced_relative(
        &mut self,
        term: Term<'a>,
    ) -> ParseResult<Option<&'a LogicExpr<'a>>> {
        if !self.peek_heads_reduced_relative_participle() {
            return Ok(None);
        }
        let mut preds: Vec<&'a LogicExpr<'a>> = Vec::new();
        // Leading ordinal/temporal adverb over the gap ("first climbed" → First(x)).
        if matches!(
            self.peek().kind,
            TokenType::Adverb(_) | TokenType::TemporalAdverb(_)
        ) {
            let adv = match self.peek().kind {
                TokenType::Adverb(s) | TokenType::TemporalAdverb(s) => s,
                _ => unreachable!(),
            };
            self.advance();
            preds.push(self.ctx.exprs.alloc(LogicExpr::Predicate {
                name: adv,
                args: self.ctx.terms.alloc_slice([term]),
                world: None,
            }));
        }
        let (red_verb, _t, _a, _c) = self.consume_verb_with_metadata();
        preds.push(self.ctx.exprs.alloc(LogicExpr::Predicate {
            name: red_verb,
            args: self.ctx.terms.alloc_slice([term]),
            world: None,
        }));
        // Complements: PP objects ("from a beetle", "in March"), directional
        // "to <NP>" ("going to Pete's"), numeric measures ("in 1845"). Mirrors the
        // post-subject reduced-relative handler.
        loop {
            let prep = if self.check_preposition() {
                match self.advance().kind {
                    TokenType::Preposition(s) => s,
                    _ => break,
                }
            } else if self.check(&TokenType::To)
                && matches!(
                    self.tokens.get(self.current + 1).map(|t| &t.kind),
                    Some(TokenType::Article(_))
                        | Some(TokenType::Noun(_))
                        | Some(TokenType::ProperName(_))
                )
            {
                self.advance();
                self.interner.intern("To")
            } else {
                break;
            };
            if self.check_number() {
                let m = self.parse_measure_phrase()?;
                preds.push(self.ctx.exprs.alloc(LogicExpr::Predicate {
                    name: prep,
                    args: self.ctx.terms.alloc_slice([term, *m]),
                    world: None,
                }));
            } else if self.check_article() || self.check_content_word() {
                let obj = self.parse_noun_phrase(true)?;
                preds.push(self.ctx.exprs.alloc(LogicExpr::Predicate {
                    name: prep,
                    args: self.ctx.terms.alloc_slice([term, Term::Constant(obj.noun)]),
                    world: None,
                }));
            } else {
                break;
            }
        }
        let mut result = preds[0];
        for p in &preds[1..] {
            result = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                left: result,
                op: TokenType::And,
                right: p,
            });
        }
        Ok(Some(result))
    }

    /// Lower ONE list member to a distinct entity. A DESCRIPTION (adjectives /
    /// possessor / PPs / relative clause — and, when `bare_definite_distinct`, a
    /// bare definite) becomes a fresh ∃-VARIABLE carrying its full restrictor
    /// (head + adjectives + possessor + PPs + relative, all over the variable);
    /// anything else is a referring CONSTANT. Returns `(term, ∃-var?, restrictor?)`.
    ///
    /// Shared by both list shapes so members lower IDENTICALLY: the list subject
    /// ("A, B and C are different X") needs every definite member distinct for the
    /// "different" distinctness (`bare_definite_distinct = true`); the enumerated
    /// identity ("The four X are A, B and C") keeps a bare named definite ("the
    /// hustle") a constant but still must not collapse a DESCRIBED member ("the
    /// person from Spain", "the winner who won") to its head (`= false`).
    fn parse_list_member_np(
        &mut self,
        np: &crate::ast::NounPhrase<'a>,
        bare_definite_distinct: bool,
    ) -> ParseResult<(Term<'a>, Option<Symbol>, Option<&'a LogicExpr<'a>>)> {
        let has_rel = self.check(&TokenType::Who)
            || self.check(&TokenType::That)
            || self.check(&TokenType::Where)
            || self.check(&TokenType::Whose);
        let is_desc = has_rel
            || (bare_definite_distinct && np.definiteness.is_some())
            || !np.adjectives.is_empty()
            || np.possessor.is_some()
            || !np.pps.is_empty();
        if is_desc {
            let var = self.next_var_name();
            let term = Term::Variable(var);
            let mut r = self.nominal_predication(term, np);
            if let Some(poss) = np.possessor {
                let possesses = self.interner.intern("Possesses");
                let pr = self.ctx.exprs.alloc(LogicExpr::Predicate {
                    name: possesses,
                    args: self.ctx.terms.alloc_slice([Term::Constant(poss.noun), term]),
                    world: None,
                });
                r = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                    left: r,
                    op: TokenType::And,
                    right: pr,
                });
            }
            for pp in np.pps {
                let pp_sub = self.substitute_pp_self_term(pp, term);
                r = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                    left: r,
                    op: TokenType::And,
                    right: pp_sub,
                });
            }
            // who/that/where/whose attach uniformly via the shared dispatcher.
            if let Some(rc) = self.try_attach_relative(term)? {
                r = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                    left: r,
                    op: TokenType::And,
                    right: rc,
                });
            }
            // A REDUCED relative ("the peak climbed in 1845", "the island first seen
            // by Captain Norris") — a participle a list member can carry but
            // parse_noun_phrase's conservative handler leaves stranded.
            if let Some(rr) = self.try_consume_reduced_relative(term)? {
                r = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                    left: r,
                    op: TokenType::And,
                    right: rr,
                });
            }
            Ok((term, Some(var), Some(r)))
        } else {
            Ok((Term::Constant(np.noun), None, None))
        }
    }

    /// Assemble an enumerated identity ("The four X are A, B and C") from an
    /// already-built first member. Parses the remaining comma/and-separated members
    /// through the shared distinct-entity builder, identifies the plural subject
    /// with the group of member terms, conjoins every member restrictor, and binds
    /// the described members' ∃ variables around the whole result.
    fn finish_enumerated_identity(
        &mut self,
        subject: &crate::ast::NounPhrase<'a>,
        is_negated: bool,
        first: (Term<'a>, Option<Symbol>, Option<&'a LogicExpr<'a>>),
    ) -> ParseResult<&'a LogicExpr<'a>> {
        let mut members: Vec<Term<'a>> = Vec::new();
        let mut member_vars: Vec<Symbol> = Vec::new();
        let mut member_restrictors: Vec<&'a LogicExpr<'a>> = Vec::new();
        let (t0, v0, r0) = first;
        members.push(t0);
        if let Some(v) = v0 {
            member_vars.push(v);
        }
        if let Some(r) = r0 {
            member_restrictors.push(r);
        }
        while self.check(&TokenType::Comma) || self.check(&TokenType::And) {
            // Consume separators ("," / "and" / ", and").
            while self.check(&TokenType::Comma) || self.check(&TokenType::And) {
                self.advance();
            }
            if !(self.check_article() || self.check_content_word()) {
                break;
            }
            let item = self.parse_noun_phrase(true)?;
            let (t, v, r) = self.parse_list_member_np(&item, false)?;
            members.push(t);
            if let Some(vv) = v {
                member_vars.push(vv);
            }
            if let Some(rr) = r {
                member_restrictors.push(rr);
            }
        }
        let group = Term::Group(self.ctx.terms.alloc_slice(members));
        let identity: &'a LogicExpr<'a> = self.ctx.exprs.alloc(LogicExpr::Identity {
            left: self.ctx.terms.alloc(Term::Constant(subject.noun)),
            right: self.ctx.terms.alloc(group),
        });
        let mut result = if is_negated {
            &*self.ctx.exprs.alloc(LogicExpr::UnaryOp {
                op: TokenType::Not,
                operand: identity,
            })
        } else {
            identity
        };
        for rc in member_restrictors {
            result = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                left: result,
                op: TokenType::And,
                right: rc,
            });
        }
        for v in member_vars.into_iter().rev() {
            result = self.ctx.exprs.alloc(LogicExpr::Quantifier {
                kind: QuantifierKind::Existential,
                variable: v,
                body: result,
                island_id: self.current_island,
            });
        }
        self.wrap_with_definiteness_full(subject, result)
    }

    /// Comma-coordinated list subject: "A, B and C are reptiles" / "A, B and C
    /// are all different animals". Distributes the predicate over each member;
    /// "(all) different" yields pairwise distinctness — the AllDifferent
    /// constraint the puzzle solver depends on. Returns `None` (restoring) when
    /// the comma does not open such a list (e.g. topicalization / apposition).
    fn try_parse_list_subject(
        &mut self,
        first: &crate::ast::NounPhrase<'a>,
    ) -> ParseResult<Option<&'a LogicExpr<'a>>> {
        let cp = self.checkpoint();
        // Each member becomes a DISTINCT entity: a DESCRIPTION (determiner /
        // adjectives / possessor / PPs / relative clause) is a fresh ∃-VARIABLE
        // carrying its restrictor (head + adjectives + possessor + PPs + rel clause,
        // all over the variable); a bare proper name is a referring CONSTANT
        // (distinct by unique-name). This makes "three different boxes" a MEANINGFUL
        // ¬x=y instead of the vacuous ¬Box=Box a shared head-noun constant gives.
        let mut member_terms: Vec<Term<'a>> = Vec::new();
        let mut member_vars: Vec<Symbol> = Vec::new();
        let mut member_restrictors: Vec<&'a LogicExpr<'a>> = Vec::new();
        macro_rules! add_member {
            ($np:expr) => {{
                let np = $np;
                match self.parse_list_member_np(&np, true) {
                    Ok((term, var, restrictor)) => {
                        member_terms.push(term);
                        if let Some(v) = var {
                            member_vars.push(v);
                        }
                        if let Some(r) = restrictor {
                            member_restrictors.push(r);
                        }
                    }
                    Err(_) => {
                        self.restore(cp);
                        return Ok(None);
                    }
                }
            }};
        }
        add_member!(*first);
        // The list gate: a comma OR "and" must follow the first member (and its
        // optional relative clause, "The juggler WHO USED BATONS, …"). A bare
        // 2-member "A and B verb"/"A and B are happy" with NO relative reaches
        // try_parse_plural_subject FIRST (the "and"-directly-after-subject gate),
        // so this path only sees DESCRIPTIVE members (a relativizer routed us
        // here) — those need the list parser's member restrictors + distinctness.
        if !self.check(&TokenType::Comma) && !self.check(&TokenType::And) {
            self.restore(cp);
            return Ok(None);
        }
        let mut saw_and = false;
        loop {
            let mut advanced = false;
            if self.check(&TokenType::Comma) {
                self.advance();
                advanced = true;
            }
            if self.check(&TokenType::And) {
                self.advance();
                saw_and = true;
                advanced = true;
            }
            if !advanced {
                break;
            }
            if !(self.check_article() || self.check_content_word()) {
                break;
            }
            let np = match self.parse_noun_phrase(true) {
                Ok(np) => np,
                Err(_) => {
                    self.restore(cp);
                    return Ok(None);
                }
            };
            add_member!(np);
        }

        // A genuine coordination needs the final "and" and ≥2 members. The
        // simple 2-member "A and B" (no relative) is try_parse_plural_subject's
        // job and never reaches here; a 2-member list that DID reach here has a
        // descriptive (relative-clause) member that the plural path can't carry,
        // so handle it ("The cat that purrs and the dog that barks are different
        // animals").
        if !saw_and || member_terms.len() < 2 {
            self.restore(cp);
            return Ok(None);
        }

        let copula_past = self.check(&TokenType::Were);
        if !(self.check(&TokenType::Are)
            || self.check(&TokenType::Were)
            || self.check(&TokenType::Is))
        {
            self.restore(cp);
            return Ok(None);
        }
        self.advance(); // copula

        if self.check(&TokenType::All) {
            self.advance();
        }

        // "are THREE different vegetables" — a cardinal that restates the member
        // count before "different" is subsumed by the pairwise distinctness, so
        // skip it (only when "different" actually follows, to stay conservative).
        if matches!(self.peek().kind, TokenType::Cardinal(_))
            && self
                .tokens
                .get(self.current + 1)
                .map(|t| self.interner.resolve(t.lexeme).eq_ignore_ascii_case("different"))
                .unwrap_or(false)
        {
            self.advance();
        }

        // Each member's restrictor (head + adjectives + possessor + PPs + relative
        // clause, over its entity term) was built during parsing — start the
        // conjunction with them so nothing is dropped.
        let mut conjuncts: Vec<&'a LogicExpr<'a>> = member_restrictors;

        let is_different = self
            .interner
            .resolve(self.peek().lexeme)
            .eq_ignore_ascii_case("different");
        if is_different {
            self.advance(); // "different"
            // Optional type noun ("animals"): predicate it of each member entity.
            if self.check_content_word() {
                let type_noun = self.consume_content_word()?;
                for t in &member_terms {
                    conjuncts.push(self.ctx.exprs.alloc(LogicExpr::Predicate {
                        name: type_noun,
                        args: self.ctx.terms.alloc_slice([*t]),
                        world: None,
                    }));
                    // A category DECLARATION ("2001, 2002, 2003, and 2004 are four
                    // different years.") records item→category in the shared
                    // discourse DRS, so a later definite LABEL ("the 2003 holiday")
                    // can recover the category and un-fuse to the same relation the
                    // prepositional-phrase form yields. Only a referring CONSTANT
                    // member names an item the label can match.
                    if let Term::Constant(item) = t {
                        self.drs.register_item_category(*item, type_noun);
                    }
                }
            }
            // Pairwise distinctness — the AllDifferent constraint over the DISTINCT
            // member entities (variables / constants), so it is non-vacuous.
            for i in 0..member_terms.len() {
                for j in (i + 1)..member_terms.len() {
                    let id = self.ctx.exprs.alloc(LogicExpr::Identity {
                        left: self.ctx.terms.alloc(member_terms[i]),
                        right: self.ctx.terms.alloc(member_terms[j]),
                    });
                    conjuncts.push(self.ctx.exprs.alloc(LogicExpr::UnaryOp {
                        op: TokenType::Not,
                        operand: id,
                    }));
                }
            }
        } else if self.check_article() || self.check_content_word() {
            // Distributive predication: each member satisfies the predicate NP.
            let pred_np = self.parse_noun_phrase(true)?;
            for t in &member_terms {
                conjuncts.push(self.ctx.exprs.alloc(LogicExpr::Predicate {
                    name: pred_np.noun,
                    args: self.ctx.terms.alloc_slice([*t]),
                    world: None,
                }));
            }
        } else {
            self.restore(cp);
            return Ok(None);
        }

        if conjuncts.is_empty() {
            self.restore(cp);
            return Ok(None);
        }
        let mut result = conjuncts[0];
        for c in &conjuncts[1..] {
            result = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                left: result,
                op: TokenType::And,
                right: c,
            });
        }
        if copula_past {
            result = self.ctx.exprs.alloc(LogicExpr::Temporal {
                operator: TemporalOperator::Past,
                body: result,
            });
        }
        // Bind each descriptive member's existential variable around the whole
        // conjunction (∃x∃y∃z(restrictors ∧ types ∧ ¬x=y ∧ …)).
        for &var in member_vars.iter().rev() {
            result = self.ctx.exprs.alloc(LogicExpr::Quantifier {
                kind: QuantifierKind::Existential,
                variable: var,
                body: result,
                island_id: self.current_island,
            });
        }
        Ok(Some(result))
    }

    fn parse_atom(&mut self) -> ParseResult<&'a LogicExpr<'a>> {
        // A fresh clause starts with no stashed subject restriction — guard
        // against a prior clause leaking one that its copula branch never
        // consumed.
        self.pending_subject_restriction = None;

        // Handle Focus particles: "Only John loves Mary", "Even John ran"
        if self.check_focus() {
            return self.parse_focus();
        }

        // Handle mass noun measure: "Much water flows", "Little time remains"
        if self.check_measure() {
            return self.parse_measure();
        }

        // Gerund subject ("Flying planes can be dangerous."): a sentence-initial
        // progressive verb + NP names an ACTIVITY; the matrix predicate applies
        // to that activity as a proposition. Gated on the full shape
        // (gerund + noun + modal/copula) so imperatives are untouched.
        if let TokenType::Verb {
            lemma,
            aspect: Aspect::Progressive,
            time: Time::None,
            ..
        } = self.peek().kind
        {
            let noun_next = matches!(
                self.tokens.get(self.current + 1).map(|t| t.kind.clone()),
                Some(TokenType::Noun(_))
            );
            let finite_after = matches!(
                self.tokens.get(self.current + 2).map(|t| t.kind.clone()),
                Some(
                    TokenType::Can
                        | TokenType::Could
                        | TokenType::May
                        | TokenType::Must
                        | TokenType::Should
                        | TokenType::Would
                        | TokenType::Is
                        | TokenType::Are
                )
            );
            if noun_next && finite_after {
                self.advance(); // gerund
                let noun_sym = match self.advance().kind {
                    TokenType::Noun(n) => n,
                    _ => unreachable!("guarded by noun_next"),
                };

                let event_var = self.get_event_var();
                let activity = self.ctx.exprs.alloc(LogicExpr::NeoEvent(Box::new(NeoEventData {
                    event_var,
                    verb: lemma,
                    roles: self
                        .ctx
                        .roles
                        .alloc_slice(vec![(ThematicRole::Theme, Term::Constant(noun_sym))]),
                    modifiers: self.ctx.syms.alloc_slice(vec![]),
                    suppress_existential: false,
                    world: None,
                })));

                let modal_tok = if matches!(
                    self.peek().kind,
                    TokenType::Can
                        | TokenType::Could
                        | TokenType::May
                        | TokenType::Must
                        | TokenType::Should
                        | TokenType::Would
                ) {
                    Some(self.advance().kind.clone())
                } else {
                    None
                };
                // Copula: bare "be" under a modal, or finite "is"/"are".
                if matches!(self.peek().kind, TokenType::Is | TokenType::Are | TokenType::Be) {
                    self.advance();
                } else if matches!(self.peek().kind, TokenType::Verb { .. })
                    && self
                        .interner
                        .resolve(self.peek().lexeme)
                        .eq_ignore_ascii_case("be")
                {
                    self.advance();
                }

                if let TokenType::Adjective(adj) = self.peek().kind {
                    self.advance();
                    let pred = self.ctx.exprs.alloc(LogicExpr::Predicate {
                        name: adj,
                        args: self.ctx.terms.alloc_slice([Term::Proposition(activity)]),
                        world: None,
                    });
                    let result = match modal_tok {
                        Some(tok) => {
                            let force = match tok {
                                TokenType::Must => 1.0,
                                TokenType::Should | TokenType::Would => 0.6,
                                TokenType::Could => 0.4,
                                _ => 0.5,
                            };
                            &*self.ctx.exprs.alloc(LogicExpr::Modal {
                                vector: crate::ast::ModalVector::new(
                                    crate::ast::ModalDomain::Alethic,
                                    force,
                                    crate::ast::ModalFlavor::Root,
                                ),
                                operand: pred,
                            })
                        }
                        None => pred,
                    };
                    return Ok(result);
                }
                return Err(ParseError {
                    kind: ParseErrorKind::ExpectedContentWord {
                        found: self.peek().kind.clone(),
                    },
                    span: self.current_span(),
                });
            }
        }

        if self.check_quantifier() {
            self.advance();
            return self.parse_quantified();
        }

        if self.check_npi_quantifier() {
            return self.parse_npi_quantified();
        }

        if self.check_temporal_npi() {
            return self.parse_temporal_npi();
        }

        if self.match_token(&[TokenType::LParen]) {
            let expr = self.parse_sentence()?;
            self.consume(TokenType::RParen)?;
            return Ok(expr);
        }

        // Handle pronoun as subject
        if self.check_pronoun() {
            let token = self.advance().clone();
            let (gender, number) = match &token.kind {
                TokenType::Pronoun { gender, number, .. } => (*gender, *number),
                TokenType::Ambiguous { primary, alternatives } => {
                    if let TokenType::Pronoun { gender, number, .. } = **primary {
                        (gender, number)
                    } else {
                        alternatives.iter().find_map(|t| {
                            if let TokenType::Pronoun { gender, number, .. } = t {
                                Some((*gender, *number))
                            } else {
                                None
                            }
                        }).unwrap_or((Gender::Unknown, Number::Singular))
                    }
                }
                _ => (Gender::Unknown, Number::Singular),
            };

            let token_text = self.interner.resolve(token.lexeme);

            // Weather verb + expletive "it" detection: "it rains" → ∃e(Rain(e))
            // Must check BEFORE pronoun resolution since "it" resolves to "?"
            if token_text.eq_ignore_ascii_case("it") && self.check_verb() {
                if let TokenType::Verb { lemma, time, .. } = &self.peek().kind {
                    let lemma_str = self.interner.resolve(*lemma);
                    if Lexer::is_weather_verb(lemma_str) {
                        let verb = *lemma;
                        let verb_time = *time;
                        self.advance(); // consume the weather verb

                        let event_var = self.get_event_var();
                        let suppress_existential = self.drs.in_conditional_antecedent();
                        if suppress_existential {
                            let event_class = self.interner.intern("Event");
                            self.drs.introduce_referent(event_var, event_class, Gender::Neuter, Number::Singular);
                        }
                        let neo_event = self.ctx.exprs.alloc(LogicExpr::NeoEvent(Box::new(NeoEventData {
                            event_var,
                            verb,
                            roles: self.ctx.roles.alloc_slice(vec![]), // No thematic roles
                            modifiers: self.ctx.syms.alloc_slice(vec![]),
                            suppress_existential,
                            world: None,
                        })));

                        return Ok(match verb_time {
                            Time::Past => self.ctx.exprs.alloc(LogicExpr::Temporal {
                                operator: TemporalOperator::Past,
                                body: neo_event,
                            }),
                            Time::Future => self.ctx.exprs.alloc(LogicExpr::Temporal {
                                operator: TemporalOperator::Future,
                                body: neo_event,
                            }),
                            _ => neo_event,
                        });
                    }
                }
            }

            // Handle deictic pronouns that don't need discourse resolution
            let resolved = if token_text.eq_ignore_ascii_case("i") {
                ResolvedPronoun::Constant(self.interner.intern("Speaker"))
            } else if token_text.eq_ignore_ascii_case("you") {
                ResolvedPronoun::Constant(self.interner.intern("Addressee"))
            } else {
                // Try discourse resolution for anaphoric pronouns
                self.resolve_pronoun(gender, number)?
            };

            // Skip the performativity marker "hereby": "I hereby resign."
            if self
                .interner
                .resolve(self.peek().lexeme)
                .eq_ignore_ascii_case("hereby")
            {
                self.advance();
            }

            // Check for performative: "I (hereby) promise to/that ...", "I hereby resign."
            if self.check_performative() {
                if let TokenType::Performative(act) = self.advance().kind.clone() {
                    let sym = match resolved {
                        ResolvedPronoun::Variable(s) | ResolvedPronoun::Constant(s) => s,
                    };

                    // Infinitive complement: "I promise to call you." The complement
                    // verb may be noun-tagged ("call"), so accept any content word and
                    // capture its object so the hearer survives (P3 structured content).
                    if self.check(&TokenType::To) {
                        self.advance(); // consume "to"

                        if !self.is_at_end() && !self.check(&TokenType::Period) {
                            // The complement verb may be lexed as a reserved keyword
                            // (e.g. "call" → TokenType::Call), so take the lexeme
                            // directly as the predicate name rather than requiring a
                            // content-word token.
                            let lexeme =
                                self.interner.resolve(self.peek().lexeme).to_string();
                            let verb_name = lexeme
                                .chars()
                                .next()
                                .map(|c| c.to_uppercase().collect::<String>() + &lexeme[1..])
                                .unwrap_or(lexeme);
                            let infinitive_verb = self.interner.intern(&verb_name);
                            self.advance(); // consume the complement verb
                            let content = self.performative_predicate(infinitive_verb, sym);
                            return Ok(self.ctx.exprs.alloc(LogicExpr::SpeechAct {
                                performer: sym,
                                act_type: act,
                                content,
                            }));
                        }
                    }

                    // Clausal complement: "I declare that S."
                    if self.check(&TokenType::That) {
                        self.advance();
                        let content = self.parse_sentence()?;
                        return Ok(self.ctx.exprs.alloc(LogicExpr::SpeechAct {
                            performer: sym,
                            act_type: act,
                            content,
                        }));
                    }

                    // Bare performative — the saying is the doing — but ONLY when the
                    // remainder is empty ("I hereby resign.") or a lone object NP
                    // ("I thank you."). Object-control performatives that take a
                    // further complement ("I order you to leave.") fall through to the
                    // standard clausal parse below so the complement is not truncated.
                    let at_end = self.check(&TokenType::Period) || self.is_at_end();
                    let lone_object_then_end = matches!(
                        self.peek().kind,
                        TokenType::Pronoun { .. } | TokenType::ProperName(_)
                    ) && self.current + 1 < self.tokens.len()
                        && matches!(
                            self.tokens[self.current + 1].kind,
                            TokenType::Period | TokenType::EOF
                        );
                    if at_end || lone_object_then_end {
                        let content = self.performative_predicate(act, sym);
                        return Ok(self.ctx.exprs.alloc(LogicExpr::SpeechAct {
                            performer: sym,
                            act_type: act,
                            content,
                        }));
                    }

                    // Fallback (object-control performatives, residual material):
                    // preserve the prior behavior of parsing the remainder as content.
                    let content = self.parse_sentence()?;
                    return Ok(self.ctx.exprs.alloc(LogicExpr::SpeechAct {
                        performer: sym,
                        act_type: act,
                        content,
                    }));
                }
            }

            // Continue parsing verb phrase with resolved subject
            // Use as_var=true for bound variables, as_var=false for constants
            return match resolved {
                ResolvedPronoun::Variable(sym) => self.parse_predicate_with_subject_as_var(sym),
                ResolvedPronoun::Constant(sym) => self.parse_predicate_with_subject(sym),
            };
        }

        // Consume "both" correlative marker if present: "both X and Y"
        // The existing try_parse_plural_subject will handle the "X and Y" pattern
        let _had_both = self.match_token(&[TokenType::Both]);

        let mut subject = self.parse_noun_phrase(true)?;

        // Floating (stranded) quantifier: "The boys all left.", "The students each
        // solved a problem.", "The boys both ran." A quantifier stranded after the
        // subject re-associates to it and distributes the predicate over its members.
        // Consume it so the (plural definite) subject's distributive reading applies.
        if self.check(&TokenType::All)
            || self.check(&TokenType::Both)
            || self.interner.resolve(self.peek().lexeme).eq_ignore_ascii_case("each")
        {
            self.advance();
            self.collective_mode = false; // force the distributive (per-member) reading
            self.distributive_marker = true;
        }

        // Introduce subject NP to DRS for cross-sentence pronoun resolution (accommodation)
        // This allows "A man walked. He fell." to work
        // Use noun as both variable and noun_class (like proper names) so pronouns resolve to it
        // NOTE: Definite NPs are NOT introduced here - they go through wrap_with_definiteness
        // where bridging anaphora can link them to prior wholes (e.g., "I bought a car. The engine smoked.")
        if subject.definiteness == Some(Definiteness::Indefinite)
            || subject.definiteness == Some(Definiteness::Distal) {
            let gender = Self::infer_noun_gender(self.interner.resolve(subject.noun));
            let number = if Self::is_plural_noun(self.interner.resolve(subject.noun)) {
                Number::Plural
            } else {
                Number::Singular
            };
            // Use noun as variable so pronoun resolution returns the noun name
            self.drs.introduce_referent(subject.noun, subject.noun, gender, number);
        }

        // Handle plural subjects: "John and Mary verb"
        if self.check(&TokenType::And) {
            match self.try_parse_plural_subject(&subject) {
                Ok(Some(result)) => return Ok(result),
                Ok(None) => {} // Not a plural subject, continue
                Err(e) => return Err(e), // Semantic error (e.g., respectively mismatch)
            }
        }

        // Handle scopal adverbs: "John almost died"
        if self.check_scopal_adverb() {
            return self.parse_scopal_adverb(&subject);
        }

        // Non-restrictive (appositive) RC (§3.1): "John, who loves Mary, left." — a
        // comma-delimited RC on a referential head is a SIDE-ASSERTION about the
        // head referent, conjoined with the main clause, NOT a restriction.
        if self.check(&TokenType::Comma)
            && matches!(
                self.tokens.get(self.current + 1).map(|t| &t.kind),
                Some(TokenType::Who) | Some(TokenType::That)
            )
        {
            self.advance(); // comma
            self.advance(); // who / which / that
            // The RC predication, with the head referent filling the gap.
            let rc = self.parse_relative_clause(subject.noun)?;
            if self.check(&TokenType::Comma) {
                self.advance(); // closing comma
            }
            // The main clause predicated of the same head.
            let main = self.parse_predicate_with_subject(subject.noun)?;
            let conj = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                left: main,
                op: TokenType::And,
                right: rc,
            });
            return self.wrap_with_definiteness_full(&subject, conj);
        }

        // Comma-coordinated list subject: "A, B and C are all different animals."
        // Also fire when a relativizer follows the first member ("The scent THAT
        // sold for $75, the white fragrance, and the purple perfume are three
        // different perfumes") — the list parser consumes the first member's
        // relative clause before the comma gate. It restores cleanly when this is
        // an ordinary relative-clause subject, so the normal handler still runs.
        if self.check(&TokenType::Comma)
            || self.check(&TokenType::Who)
            || self.check(&TokenType::That)
            // "and" too: try_parse_plural_subject (called above) handles the simple
            // "A and B verb"/"A and B are happy" and returned None here only when a
            // member it can't carry follows (a relative clause on the SECOND member:
            // "Mr. Gray's timepiece and the timepiece THAT sold for $1,800 were
            // different clocks"). The list parser carries descriptive members; it
            // restores cleanly if this is not a coordinated list.
            || self.check(&TokenType::And)
            // A reduced-relative participle on the first member ("The peak CLIMBED
            // in 1845, …, and X are three different mountains") — the bare NP stops
            // at the head, so the comma is hidden behind the participle; route in so
            // the list parser consumes the reduced relative per member. An enumerated
            // list needs a comma before the clause end, so gate on one: a plain main
            // clause ("The team won in 1989") then never triggers the speculation.
            || (self.peek_heads_reduced_relative_participle() && self.has_comma_before_clause_end())
        {
            if let Some(result) = self.try_parse_list_subject(&subject)? {
                return Ok(result);
            }
        }

        // Handle topicalization: "The cake, John ate." - first NP is object, not subject
        if self.check(&TokenType::Comma) {
            let saved_pos = self.current;
            self.advance(); // consume comma

            // Check if followed by pronoun subject (e.g., "The book, he read.")
            if self.check_pronoun() {
                let topic_attempt = self.try_parse(|p| {
                    let token = p.peek().clone();
                    let pronoun_features = match &token.kind {
                        TokenType::Pronoun { gender, number, .. } => Some((*gender, *number)),
                        TokenType::Ambiguous { primary, alternatives } => {
                            if let TokenType::Pronoun { gender, number, .. } = **primary {
                                Some((gender, number))
                            } else {
                                alternatives.iter().find_map(|t| {
                                    if let TokenType::Pronoun { gender, number, .. } = t {
                                        Some((*gender, *number))
                                    } else {
                                        None
                                    }
                                })
                            }
                        }
                        _ => None,
                    };

                    if let Some((gender, number)) = pronoun_features {
                        p.advance(); // consume pronoun
                        let resolved = p.resolve_pronoun(gender, number)?;
                        let resolved_term = match resolved {
                            ResolvedPronoun::Variable(s) => Term::Variable(s),
                            ResolvedPronoun::Constant(s) => Term::Constant(s),
                        };

                        if p.check_verb() {
                            let verb = p.consume_verb();
                            let predicate = p.ctx.exprs.alloc(LogicExpr::Predicate {
                                name: verb,
                                args: p.ctx.terms.alloc_slice([
                                    resolved_term,
                                    Term::Constant(subject.noun),
                                ]),
                                world: None,
                            });
                            p.wrap_with_definiteness_full(&subject, predicate)
                        } else {
                            Err(ParseError {
                                kind: ParseErrorKind::ExpectedVerb { found: p.peek().kind.clone() },
                                span: p.current_span(),
                            })
                        }
                    } else {
                        Err(ParseError {
                            kind: ParseErrorKind::ExpectedContentWord { found: token.kind },
                            span: p.current_span(),
                        })
                    }
                });

                if let Some(result) = topic_attempt {
                    return Ok(result);
                }
            }

            // Check if followed by another NP and then a verb (topicalization pattern)
            if self.check_content_word() {
                let topic_attempt = self.try_parse(|p| {
                    let real_subject = p.parse_noun_phrase(true)?;
                    if p.check_verb() {
                        let verb = p.consume_verb();
                        let predicate = p.ctx.exprs.alloc(LogicExpr::Predicate {
                            name: verb,
                            args: p.ctx.terms.alloc_slice([
                                Term::Constant(real_subject.noun),
                                Term::Constant(subject.noun),
                            ]),
                            world: None,
                        });
                        p.wrap_with_definiteness_full(&subject, predicate)
                    } else {
                        Err(ParseError {
                            kind: ParseErrorKind::ExpectedVerb { found: p.peek().kind.clone() },
                            span: p.current_span(),
                        })
                    }
                });

                if let Some(result) = topic_attempt {
                    return Ok(result);
                }
            }

            // Restore position if topicalization didn't match
            self.current = saved_pos;
        }

        // Handle relative clause after subject: "The cat that the dog chased ran."
        let mut relative_clause: Option<(Symbol, &'a LogicExpr<'a>)> = None;
        if self.check(&TokenType::That) || self.check(&TokenType::Who) {
            self.advance();
            let var_name = self.next_var_name();
            let rel_pred = self.parse_relative_clause(var_name)?;
            relative_clause = Some((var_name, rel_pred));
        } else if self.check(&TokenType::Where) {
            // Locative/circumstance relative: "the episode WHERE the survivor brought
            // the knife", "the trip WHERE they saw 16 stars". Unlike who/that (an
            // argument gap), the clause has its OWN subject and the head is the
            // LOCATION/occasion of the event — so parse the embedded subject + its full
            // VP and conjoin In(event, head) over the gap. Without this the clue
            // stranded at "where" (TrailingTokens).
            let var_name = self.next_var_name();
            let rel_pred = self.parse_where_relative(var_name)?;
            relative_clause = Some((var_name, rel_pred));
        } else if matches!(self.peek().kind, TokenType::Article(_)) && self.is_contact_clause_pattern() {
            // Contact clause (reduced relative): "The cat the dog chased ran."
            // NP + NP + Verb pattern indicates embedded relative without explicit "that"
            let var_name = self.next_var_name();
            let rel_pred = self.parse_relative_clause(var_name)?;
            relative_clause = Some((var_name, rel_pred));
        }

        // Handle main verb after relative clause: "The cat that the dog chased ran."
        if let Some((var_name, rel_clause)) = relative_clause {
            // Aspectual / presupposition-trigger matrix over a relativized subject
            // ("the person WHO WON STARTED skydiving 2 years after Leslie") — the
            // SAME presupposition grammar as a bare subject, via the term-parametric
            // form, so the feature composes with relative-clause subjects.
            if self.check_presup_trigger()
                && !self.is_followed_by_np_object()
                && self.is_followed_by_gerund()
            {
                let presup_kind = self.consume_presup_trigger();
                let main_pred =
                    self.parse_presupposition_for_term(Term::Variable(var_name), presup_kind, false)?;
                let type_pred = self.ctx.exprs.alloc(LogicExpr::Predicate {
                    name: subject.noun,
                    args: self.ctx.terms.alloc_slice([Term::Variable(var_name)]),
                    world: None,
                });
                let inner = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                    left: type_pred,
                    op: TokenType::And,
                    right: rel_clause,
                });
                let body = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                    left: inner,
                    op: TokenType::And,
                    right: main_pred,
                });
                return Ok(self.ctx.exprs.alloc(LogicExpr::Quantifier {
                    kind: QuantifierKind::Existential,
                    variable: var_name,
                    body,
                    island_id: self.current_island,
                }));
            }
            if self.check_verb() {
                let (verb, verb_time, _, _) = self.consume_verb_with_metadata();
                let var_term = Term::Variable(var_name);

                // A bare verb keeps the simple event; material after it
                // ("The farmer who saw a cat CHASED IT.") takes the full VP
                // grammar over the relativized variable.
                let main_pred = if self.at_clause_boundary() {
                    let event_var = self.get_event_var();
                    let suppress_existential = self.drs.in_conditional_antecedent();
                    let mut modifiers = vec![];
                    if verb_time == Time::Past {
                        modifiers.push(self.interner.intern("Past"));
                    }
                    &*self.ctx.exprs.alloc(LogicExpr::NeoEvent(Box::new(NeoEventData {
                        event_var,
                        verb,
                        roles: self.ctx.roles.alloc_slice(vec![
                            (ThematicRole::Agent, var_term),
                        ]),
                        modifiers: self.ctx.syms.alloc_slice(modifiers),
                        suppress_existential,
                        world: None,
                    })))
                } else {
                    self.current -= 1; // hand the verb back to the VP parser
                    self.parse_predicate_with_subject_as_var(var_name)?
                };

                let type_pred = self.ctx.exprs.alloc(LogicExpr::Predicate {
                    name: subject.noun,
                    args: self.ctx.terms.alloc_slice([Term::Variable(var_name)]),
                    world: None,
                });

                let inner = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                    left: type_pred,
                    op: TokenType::And,
                    right: rel_clause,
                });

                let body = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                    left: inner,
                    op: TokenType::And,
                    right: main_pred,
                });

                return Ok(self.ctx.exprs.alloc(LogicExpr::Quantifier {
                    kind: QuantifierKind::Existential,
                    variable: var_name,
                    body,
                    island_id: self.current_island,
                }));
            }

            // No main verb - just the relative clause: "The cat that runs" as a complete NP
            // Build: ∃x(Cat(x) ∧ Runs(x) ∧ ∀y(Cat(y) → y=x))
            if self.is_at_end() || self.check(&TokenType::Period) || self.check(&TokenType::Comma) {
                let type_pred = self.ctx.exprs.alloc(LogicExpr::Predicate {
                    name: subject.noun,
                    args: self.ctx.terms.alloc_slice([Term::Variable(var_name)]),
                    world: None,
                });

                let body = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                    left: type_pred,
                    op: TokenType::And,
                    right: rel_clause,
                });

                // Add uniqueness for definite description
                let uniqueness_body = if subject.definiteness == Some(Definiteness::Definite) {
                    let y_var = self.next_var_name();
                    let type_pred_y = self.ctx.exprs.alloc(LogicExpr::Predicate {
                        name: subject.noun,
                        args: self.ctx.terms.alloc_slice([Term::Variable(y_var)]),
                        world: None,
                    });
                    let identity = self.ctx.exprs.alloc(LogicExpr::Identity {
                        left: self.ctx.terms.alloc(Term::Variable(y_var)),
                        right: self.ctx.terms.alloc(Term::Variable(var_name)),
                    });
                    let uniqueness_cond = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                        left: type_pred_y,
                        op: TokenType::Implies,
                        right: identity,
                    });
                    let uniqueness = self.ctx.exprs.alloc(LogicExpr::Quantifier {
                        kind: QuantifierKind::Universal,
                        variable: y_var,
                        body: uniqueness_cond,
                        island_id: self.current_island,
                    });
                    self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                        left: body,
                        op: TokenType::And,
                        right: uniqueness,
                    })
                } else {
                    body
                };

                return Ok(self.ctx.exprs.alloc(LogicExpr::Quantifier {
                    kind: QuantifierKind::Existential,
                    variable: var_name,
                    body: uniqueness_body,
                    island_id: self.current_island,
                }));
            }

            // Re-store for copula handling below
            relative_clause = Some((var_name, rel_clause));
        }

        // Identity check: "Clark is equal to Superman"
        if self.check(&TokenType::Identity) {
            self.advance();
            let right = self.consume_content_word()?;
            return Ok(self.ctx.exprs.alloc(LogicExpr::Identity {
                left: self.ctx.terms.alloc(Term::Constant(subject.noun)),
                right: self.ctx.terms.alloc(Term::Constant(right)),
            }));
        }

        if self.check_modal() {
            if let Some((var_name, rel_clause)) = relative_clause {
                let modal_pred = self.parse_aspect_chain_with_term(Term::Variable(var_name))?;

                let type_pred = self.ctx.exprs.alloc(LogicExpr::Predicate {
                    name: subject.noun,
                    args: self.ctx.terms.alloc_slice([Term::Variable(var_name)]),
                    world: None,
                });

                let inner = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                    left: type_pred,
                    op: TokenType::And,
                    right: rel_clause,
                });

                let body = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                    left: inner,
                    op: TokenType::And,
                    right: modal_pred,
                });

                return Ok(self.ctx.exprs.alloc(LogicExpr::Quantifier {
                    kind: QuantifierKind::Existential,
                    variable: var_name,
                    body,
                    island_id: self.current_island,
                }));
            }

            let modal_pred = self.parse_aspect_chain(subject.noun)?;
            return self.wrap_with_definiteness_full(&subject, modal_pred);
        }

        // Reduced relative clause on the subject before a copular matrix
        // predicate: "The drug sourced from a beetle is X.", "The mushroom going
        // to Pete's is Y.", "The raptor belonging to Ivan is trained by Z." A
        // participle directly after the subject — followed, once its complements
        // are consumed, by the matrix copula — restricts the subject (it is NOT
        // the matrix verb). Parse it as restriction predicates over the subject
        // and fold them into the subject's PPs, so the existing copular path then
        // predicates the rest. Backtracking: commit only if a copula truly
        // follows, so a finite main verb ("The drug treats X") is untouched.
        // An auxiliary (have/be/do) heads a perfect/passive/progressive matrix
        // ("The apple has been eaten."), NOT a reduced relative — never treat it
        // as the participle.
        // A reduced relative may carry a leading ordinal/temporal adverb ("The peak
        // FIRST climbed in 1845 is tall.", "The island FIRST seen by Captain Norris
        // is small."). The adverb hides the participle from the verb check below; look
        // one token past a single leading adverb to find the participle that heads the
        // relative, and consume it inside the speculative parse so the token survives
        // as a modifier on the subject.
        let leading_adverb = if matches!(
            self.peek().kind,
            TokenType::Adverb(_) | TokenType::TemporalAdverb(_)
        ) && self
            .tokens
            .get(self.current + 1)
            .map_or(false, |t| self.kind_is_verb(&t.kind))
        {
            match self.peek().kind {
                TokenType::Adverb(s) | TokenType::TemporalAdverb(s) => Some(s),
                _ => None,
            }
        } else {
            None
        };
        let head_verb_idx = if leading_adverb.is_some() {
            self.current + 1
        } else {
            self.current
        };
        let head_verb_is_aux = if let Some(TokenType::Verb { lemma, .. }) =
            self.tokens.get(head_verb_idx).map(|t| &t.kind)
        {
            matches!(
                self.interner.resolve(*lemma).to_lowercase().as_str(),
                "have" | "be" | "do"
            )
        } else {
            false
        };
        let heads_reduced_rel = self
            .tokens
            .get(head_verb_idx)
            .map_or(false, |t| self.kind_is_verb(&t.kind));
        if subject.definiteness.is_some()
            && heads_reduced_rel
            && self.pending_time.is_none()
            && !head_verb_is_aux
        {
            if let Some(restrs) = self.try_parse(|p| {
                let placeholder = p.interner.intern("_PP_SELF_");
                let mut preds: Vec<&'a LogicExpr<'a>> = Vec::new();
                if let Some(adv) = leading_adverb {
                    p.advance();
                    preds.push(p.ctx.exprs.alloc(LogicExpr::Predicate {
                        name: adv,
                        args: p.ctx.terms.alloc_slice([Term::Variable(placeholder)]),
                        world: None,
                    }));
                }
                let (red_verb, _t, _a, _c) = p.consume_verb_with_metadata();
                preds.push(p.ctx.exprs.alloc(LogicExpr::Predicate {
                    name: red_verb,
                    args: p.ctx.terms.alloc_slice([Term::Variable(placeholder)]),
                    world: None,
                }));
                // Complements: PP objects ("from a beetle", "in March"),
                // directional "to <NP>" ("going to Pete's"), numeric measures.
                loop {
                    let prep = if p.check_preposition() {
                        match p.advance().kind {
                            TokenType::Preposition(s) => s,
                            _ => break,
                        }
                    } else if p.check(&TokenType::To)
                        && matches!(
                            p.tokens.get(p.current + 1).map(|t| &t.kind),
                            Some(TokenType::Article(_))
                                | Some(TokenType::Noun(_))
                                | Some(TokenType::ProperName(_))
                        )
                    {
                        p.advance(); // "to" (directional, NP object follows)
                        p.interner.intern("To")
                    } else {
                        break;
                    };
                    if p.check_number() {
                        let m = p.parse_measure_phrase()?;
                        preds.push(p.ctx.exprs.alloc(LogicExpr::Predicate {
                            name: prep,
                            args: p.ctx.terms.alloc_slice([Term::Variable(placeholder), *m]),
                            world: None,
                        }));
                    } else if p.check_article() || p.check_content_word() {
                        let obj = p.parse_noun_phrase(true)?;
                        preds.push(p.ctx.exprs.alloc(LogicExpr::Predicate {
                            name: prep,
                            args: p
                                .ctx
                                .terms
                                .alloc_slice([Term::Variable(placeholder), Term::Constant(obj.noun)]),
                            world: None,
                        }));
                    } else {
                        break;
                    }
                }
                // Commit only if the matrix predicate follows — a copula, a FINITE
                // main verb, or a do-support / perfect AUXILIARY heading the matrix
                // VP. The "participle (+ complements) THEN a matrix predicate" pattern
                // is the reduced-relative signature ("the box [found on May 3] HELD the
                // ring", "the book [priced at $55] DOESN'T have a cover", "the well
                // [cut through gravel] HAD a leak"); a lone main verb ("The box found
                // the key") has no matrix here, so it backtracks and keeps its verb
                // reading. The matrix verb must be FINITE — an -ing (progressive) form
                // is not a finite matrix verb but a gerund modifier of the verb's
                // object ("used BOWLING pins"), so it must NOT trigger the reading.
                let matrix_finite_verb = matches!(
                    p.peek().kind,
                    TokenType::Verb { aspect, .. } if !matches!(aspect, Aspect::Progressive)
                );
                if !(p.check(&TokenType::Is)
                    || p.check(&TokenType::Are)
                    || p.check(&TokenType::Was)
                    || p.check(&TokenType::Were)
                    || p.check(&TokenType::Does)
                    || p.check(&TokenType::Do)
                    || p.check(&TokenType::Had)
                    || matrix_finite_verb)
                {
                    return Err(ParseError {
                        kind: ParseErrorKind::ExpectedCopula,
                        span: p.current_span(),
                    });
                }
                Ok(preds)
            }) {
                let mut pps: Vec<&'a LogicExpr<'a>> = subject.pps.to_vec();
                pps.extend(restrs);
                subject = crate::ast::NounPhrase {
                    pps: self.ctx.pps.alloc_slice(pps),
                    ..subject
                };
            }
        }

        // Bare-plural copular subject = kind predication (§6.1):
        // "Penguins are birds." → Gen x(Penguin(x) → Bird(x)), never the
        // ordinary individual-level copular path.
        if (self.check(&TokenType::Are) || self.check(&TokenType::Is))
            && subject.definiteness.is_none()
            && subject.possessor.is_none()
        {
            let noun_str = self.interner.resolve(subject.noun);
            let lower = noun_str.to_lowercase();
            let is_known_plural = Self::is_plural_noun(noun_str)
                && (crate::lexicon::is_common_noun(&lower)
                    || matches!(
                        crate::lexicon::analyze_word(&lower),
                        Some(crate::lexicon::WordAnalysis::Noun(_))
                    ));
            let nominal_or_adj_follows = matches!(
                self.tokens.get(self.current + 1).map(|t| &t.kind),
                Some(TokenType::Noun(_))
                    | Some(TokenType::Adjective(_))
                    | Some(TokenType::Article(_))
            );
            if is_known_plural && nominal_or_adj_follows {
                self.advance(); // copula
                let negated = self.check(&TokenType::Not);
                if negated {
                    self.advance();
                }
                if self.check_article() {
                    self.advance();
                }
                let var_name = self.next_var_name();
                let type_pred = self.ctx.exprs.alloc(LogicExpr::Predicate {
                    name: subject.noun,
                    args: self.ctx.terms.alloc_slice([Term::Variable(var_name)]),
                    world: None,
                });
                let pred_name = match self.peek().kind {
                    TokenType::Noun(s) | TokenType::Adjective(s) => {
                        self.advance();
                        s
                    }
                    _ => self.consume_content_word()?,
                };
                let mut nucleus: &'a LogicExpr<'a> =
                    self.ctx.exprs.alloc(LogicExpr::Predicate {
                        name: pred_name,
                        args: self.ctx.terms.alloc_slice([Term::Variable(var_name)]),
                        world: None,
                    });
                if negated {
                    nucleus = self.ctx.exprs.alloc(LogicExpr::UnaryOp {
                        op: TokenType::Not,
                        operand: nucleus,
                    });
                }
                let body = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                    left: type_pred,
                    op: TokenType::Implies,
                    right: nucleus,
                });
                return Ok(self.ctx.exprs.alloc(LogicExpr::Quantifier {
                    kind: QuantifierKind::Generic,
                    variable: var_name,
                    body,
                    island_id: self.current_island,
                }));
            }
        }

        // A relative-clause subject feeding a copula ("The scent that sold for
        // $75 is the white fragrance.") — stash the restriction, rewritten over
        // the subject constant, so the copula's wrap_with_definiteness re-binds
        // it instead of silently dropping it. The copula branches all key their
        // predicate on Constant(subject.noun), so the fold unifies cleanly.
        if let Some((rc_var, rc_pred)) = relative_clause {
            if self.check(&TokenType::Is) || self.check(&TokenType::Are)
                || self.check(&TokenType::Was) || self.check(&TokenType::Were)
            {
                let restr =
                    self.substitute_variable_with_constant(rc_pred, rc_var, subject.noun)?;
                self.pending_subject_restriction = Some((subject.noun, restr));
            }
        }

        if self.check(&TokenType::Is) || self.check(&TokenType::Are)
            || self.check(&TokenType::Was) || self.check(&TokenType::Were)
        {
            let copula_time = if self.check(&TokenType::Was) || self.check(&TokenType::Were) {
                Time::Past
            } else {
                Time::Present
            };
            self.advance();

            // Check for negation: "was not caught", "is not happy"
            let is_negated = self.check(&TokenType::Not);
            if is_negated {
                self.advance(); // consume "not"
            }

            // Check for temporal adverbs after copula: "is always Y", "is never Y"
            let mut copula_temporal = None;
            if !is_negated {
                if self.check(&TokenType::Never) {
                    self.advance();
                    copula_temporal = Some(CopulaTemporal::Never);
                } else if let TokenType::Adverb(sym) | TokenType::ScopalAdverb(sym) | TokenType::TemporalAdverb(sym) = &self.peek().kind {
                    let resolved = self.interner.resolve(*sym).to_string();
                    if resolved == "Always" || resolved == "always" {
                        self.advance();
                        copula_temporal = Some(CopulaTemporal::Always);
                    } else if resolved == "Eventually" || resolved == "eventually" {
                        self.advance();
                        copula_temporal = Some(CopulaTemporal::Eventually);
                    }
                }
            }

            // Membership partitive: "Tom is one of the boys." → Boy(Tom).
            // Member-of-the-sum is atomic parthood in the Link lattice, which
            // for a definite plural is just the noun predicate (§5.4/§6.2).
            if matches!(self.peek().kind, TokenType::Cardinal(1)) {
                let of_follows = matches!(
                    self.tokens.get(self.current + 1).map(|t| &t.kind),
                    Some(TokenType::Preposition(p)) if self.interner.resolve(*p).eq_ignore_ascii_case("of")
                );
                let article_then_noun = matches!(
                    self.tokens.get(self.current + 2).map(|t| &t.kind),
                    Some(TokenType::Article(_))
                ) && matches!(
                    self.tokens.get(self.current + 3).map(|t| &t.kind),
                    Some(TokenType::Noun(_))
                );
                if of_follows && article_then_noun {
                    self.advance(); // "one"
                    self.advance(); // "of"
                    self.advance(); // "the"
                    let noun_sym = match self.advance().kind {
                        TokenType::Noun(s) => s,
                        _ => unreachable!("guarded by article_then_noun"),
                    };
                    let noun_str = self.interner.resolve(noun_sym).to_string();
                    let singular = Self::singularize_noun(&noun_str);
                    let name_sym = self.interner.intern(&singular);
                    let mut result: &'a LogicExpr<'a> =
                        self.ctx.exprs.alloc(LogicExpr::Predicate {
                            name: name_sym,
                            args: self.ctx.terms.alloc_slice([Term::Constant(subject.noun)]),
                            world: None,
                        });
                    if is_negated {
                        result = self.ctx.exprs.alloc(LogicExpr::UnaryOp {
                            op: TokenType::Not,
                            operand: result,
                        });
                    }
                    return self.wrap_with_definiteness_full(&subject, result);
                }
            }

            // A degree adverb directly before a comparative ("is somewhat shorter
            // than", "is slightly wider than") must be skipped here so the
            // comparative branch fires — otherwise it is read as a bare adjective
            // complement and the comparative strands. The degree-adverb class is a
            // closed lexical category (lexicon `degree_adverbs`), not a parser list,
            // so a real adjective complement ("is happy") is untouched.
            if matches!(
                self.tokens.get(self.current + 1).map(|t| &t.kind),
                Some(TokenType::Comparative(_))
            ) && lexicon::is_degree_adverb(
                &self.interner.resolve(self.peek().lexeme).to_lowercase(),
            ) {
                self.advance(); // degree adverb
            }

            // Check for Number token (measure phrase) before comparative or adjective
            // "John is 2 inches taller than Mary" or "The rope is 5 meters long"
            if self.check_number() {
                let measure = self.parse_measure_phrase()?;

                // Check if followed by comparative: "2 inches taller than"
                if self.check_comparative() {
                    return self.parse_comparative(&subject, copula_time, Some(measure));
                }

                // Check for dimensional adjective: "5 meters long"
                if self.check_content_word() {
                    let adj = self.consume_content_word()?;
                    let result = self.ctx.exprs.alloc(LogicExpr::Predicate {
                        name: adj,
                        args: self.ctx.terms.alloc_slice([
                            Term::Constant(subject.noun),
                            *measure,
                        ]),
                        world: None,
                    });
                    return self.wrap_with_definiteness_full(&subject, result);
                }

                // Bare measure phrase: "The temperature is 98.6 degrees."
                // Output: Identity(subject, measure)
                if self.check(&TokenType::Period) || self.is_at_end() {
                    // In imperative mode, reject "x is 5" - suggest "x equals 5"
                    if self.mode == ParserMode::Imperative {
                        let variable = self.interner.resolve(subject.noun).to_string();
                        let value = if let Term::Value { kind, .. } = measure {
                            format!("{:?}", kind)
                        } else {
                            "value".to_string()
                        };
                        return Err(ParseError {
                            kind: ParseErrorKind::IsValueEquality { variable, value },
                            span: self.current_span(),
                        });
                    }
                    let result = self.ctx.exprs.alloc(LogicExpr::Identity {
                        left: self.ctx.terms.alloc(Term::Constant(subject.noun)),
                        right: measure,
                    });
                    return self.wrap_with_definiteness_full(&subject, result);
                }
            }

            // Check for equative: "is as tall as Y" → an at-least (≥) comparison.
            if self.interner.resolve(self.peek().lexeme).eq_ignore_ascii_case("as") {
                return self.parse_equative(&subject);
            }

            // Check for comparative: "is taller than"
            if self.check_comparative() {
                return self.parse_comparative(&subject, copula_time, None);
            }

            // Check for existential "is": "God is." - bare copula followed by period/EOF
            if self.check(&TokenType::Period) || self.is_at_end() {
                let var = self.next_var_name();
                let body = self.ctx.exprs.alloc(LogicExpr::Identity {
                    left: self.ctx.terms.alloc(Term::Variable(var)),
                    right: self.ctx.terms.alloc(Term::Constant(subject.noun)),
                });
                return Ok(self.ctx.exprs.alloc(LogicExpr::Quantifier {
                    kind: QuantifierKind::Existential,
                    variable: var,
                    body,
                    island_id: self.current_island,
                }));
            }

            // Check for superlative: "is the tallest man"
            if self.check(&TokenType::Article(Definiteness::Definite)) {
                let saved_pos = self.current;
                self.advance();
                if self.check_superlative() {
                    return self.parse_superlative(&subject);
                }
                self.current = saved_pos;
            }

            // Check for predicate NP: "Juliet is the sun" or "John is a man"
            if self.check_article() {
                // The copula is already consumed, so a verb-word in the predicate
                // NP can never be the matrix verb — it is a deverbal noun head
                // ("is the orange PACK", "is the Russell Road PROJECT").
                let saved_ctx = self.nominal_np_context;
                self.nominal_np_context = true;
                let predicate_np_result = self.parse_noun_phrase(true);
                self.nominal_np_context = saved_ctx;
                let predicate_np = predicate_np_result?;
                let predicate_noun = predicate_np.noun;

                // Enumerated identity: "The four dances are the hustle, the
                // lindy, the twist, and the waltz." A genuine comma list (≥3
                // members) identifies the plural subject with the group; a bare
                // "is a doctor and wealthy" is predication conjunction, not a
                // group identity, so a comma is required to enter this path.
                // A who/that relative on the FIRST member hides the comma that
                // opens the list ("The four winners are the winner WHO won, the
                // runner-up, …"). Speculatively consume the member-with-relative and
                // commit only if a comma actually follows; otherwise restore exactly
                // so the single "X is the Y who Z" copula path below runs unchanged.
                if self.check(&TokenType::Who) || self.check(&TokenType::That) {
                    let rel_cp = self.checkpoint();
                    if let Ok(first) = self.parse_list_member_np(&predicate_np, false) {
                        if self.check(&TokenType::Comma) {
                            return self.finish_enumerated_identity(&subject, is_negated, first);
                        }
                    }
                    self.restore(rel_cp);
                }
                if self.check(&TokenType::Comma) {
                    let first = self.parse_list_member_np(&predicate_np, false)?;
                    return self.finish_enumerated_identity(&subject, is_negated, first);
                }

                // Phase 41: Event adjective reading
                // "beautiful dancer" in event mode → ∃e(Dance(e) ∧ Agent(e, x) ∧ Beautiful(e))
                if self.event_reading_mode {
                    let noun_str = self.interner.resolve(predicate_noun);
                    if let Some(base_verb) = lexicon::lookup_agentive_noun(noun_str) {
                        // Check if any adjective can modify events
                        let event_adj = predicate_np.adjectives.iter().find(|adj| {
                            lexicon::is_event_modifier_adjective(self.interner.resolve(**adj))
                        });

                        if let Some(&adj_sym) = event_adj {
                            // Build event reading: ∃e(Verb(e) ∧ Agent(e, subject) ∧ Adj(e))
                            let verb_sym = self.interner.intern(base_verb);
                            let event_var = self.get_event_var();

                            let verb_pred = self.ctx.exprs.alloc(LogicExpr::Predicate {
                                name: verb_sym,
                                args: self.ctx.terms.alloc_slice([Term::Variable(event_var)]),
                                world: None,
                            });

                            let agent_pred = self.ctx.exprs.alloc(LogicExpr::Predicate {
                                name: self.interner.intern("Agent"),
                                args: self.ctx.terms.alloc_slice([
                                    Term::Variable(event_var),
                                    Term::Constant(subject.noun),
                                ]),
                                world: None,
                            });

                            let adj_pred = self.ctx.exprs.alloc(LogicExpr::Predicate {
                                name: adj_sym,
                                args: self.ctx.terms.alloc_slice([Term::Variable(event_var)]),
                                world: None,
                            });

                            // Conjoin: Verb(e) ∧ Agent(e, x)
                            let verb_agent = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                                left: verb_pred,
                                op: TokenType::And,
                                right: agent_pred,
                            });

                            // Conjoin: (Verb(e) ∧ Agent(e, x)) ∧ Adj(e)
                            let body = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                                left: verb_agent,
                                op: TokenType::And,
                                right: adj_pred,
                            });

                            // Wrap in existential: ∃e(...)
                            let event_reading = self.ctx.exprs.alloc(LogicExpr::Quantifier {
                                kind: QuantifierKind::Existential,
                                variable: event_var,
                                body,
                                island_id: self.current_island,
                            });

                            return self.wrap_with_definiteness_full(&subject, event_reading);
                        }
                    }
                }

                let subject_sort = lexicon::lookup_sort(self.interner.resolve(subject.noun));
                let predicate_sort = lexicon::lookup_sort(self.interner.resolve(predicate_noun));

                if let (Some(s_sort), Some(p_sort)) = (subject_sort, predicate_sort) {
                    if !s_sort.is_compatible_with(p_sort) && !p_sort.is_compatible_with(s_sort) {
                        let metaphor: &'a LogicExpr<'a> = self.ctx.exprs.alloc(LogicExpr::Metaphor {
                            tenor: self.ctx.terms.alloc(Term::Constant(subject.noun)),
                            vehicle: self.ctx.terms.alloc(Term::Constant(predicate_noun)),
                        });
                        let metaphor = if is_negated {
                            &*self.ctx.exprs.alloc(LogicExpr::UnaryOp {
                                op: TokenType::Not,
                                operand: metaphor,
                            })
                        } else {
                            metaphor
                        };
                        return self.wrap_with_definiteness_full(&subject, metaphor);
                    }
                }

                // Default: intersective reading for adjectives
                // Build Adj1(x) ∧ Adj2(x) ∧ ... ∧ Noun(x)
                let mut predicates: Vec<&'a LogicExpr<'a>> = Vec::new();

                // Add adjective predicates
                for &adj_sym in predicate_np.adjectives {
                    let adj_pred = self.ctx.exprs.alloc(LogicExpr::Predicate {
                        name: adj_sym,
                        args: self.ctx.terms.alloc_slice([Term::Constant(subject.noun)]),
                        world: None,
                    });
                    predicates.push(adj_pred);
                }

                // Add noun predicate
                let noun_pred = self.ctx.exprs.alloc(LogicExpr::Predicate {
                    name: predicate_noun,
                    args: self.ctx.terms.alloc_slice([Term::Constant(subject.noun)]),
                    world: None,
                });
                predicates.push(noun_pred);

                // A predicate-nominal genitive ("X is the Woodard family's house",
                // "X is the red team's trophy") binds the possessor to the subject.
                // Routed through the shared possessor lowering so a MODIFIED possessor
                // keeps its restrictor (∃p(Team(p) ∧ Red(p) ∧ Possesses(p, X))) instead
                // of collapsing to a bare constant that drops "red" — a meaning-loss
                // parse the prover can't use.
                if let Some(possessor) = predicate_np.possessor {
                    let poss_pred =
                        self.possessor_predication(possessor, Term::Constant(subject.noun));
                    predicates.push(poss_pred);
                }

                // The predicate nominal's PP restrictors ("X is the gator FROM Lynn",
                // "the gator CAUGHT in Lynn", "the doll 80 years OLD") are predicated of
                // the subject; dropping them is meaning loss. Each pp is written over the
                // _PP_SELF_ placeholder — rebind it to the subject. Only the pps are
                // merged here (not the whole block via nominal_predication_with_pps),
                // because the metaphor / sort-incompatibility / event-adjective readings
                // above are intersective-reading-specific and must stay reachable.
                for pp in predicate_np.pps {
                    let pp_sub = self.substitute_pp_self_term(pp, Term::Constant(subject.noun));
                    predicates.push(pp_sub);
                }

                // Conjoin all predicates
                let mut result = if predicates.len() == 1 {
                    predicates[0]
                } else {
                    let mut combined = predicates[0];
                    for pred in &predicates[1..] {
                        combined = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                            left: combined,
                            op: TokenType::And,
                            right: *pred,
                        });
                    }
                    combined
                };

                // A relative clause on the predicate nominal ("X is the player
                // WHO played", "X was the one THAT won 9 games") is predicated of
                // the SUBJECT — being that player entails X played. The gap binds
                // to the subject constant, and the restriction-VP composes its own
                // features (objects, counting NPs). Previously "who"/"that" here
                // stranded (TrailingTokens), failing every "X is the Y who/that Z".
                let mut result = result;
                if let Some(rc) = self.try_attach_relative(Term::Constant(subject.noun))? {
                    result = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                        left: result,
                        op: TokenType::And,
                        right: rc,
                    });
                }

                // Non-parallel copula coordination: "Mary is a doctor and wealthy"
                // / "is a doctor and a lawyer" — each conjunct predicates the SAME
                // subject (a comma list ≥3 is group identity, handled above). Stop
                // at anything that isn't an adjective or article-NP complement so a
                // genuine clause coordination ("… and Bob runs") is left intact.
                loop {
                    if !self.check(&TokenType::And) {
                        break;
                    }
                    let save = self.current;
                    self.advance(); // "and"
                    // A bare predicate word (adjective, or a noun the lexicon
                    // didn't mark adjectival like "wealthy") is a shared predicate;
                    // a noun is only taken when a clause boundary / "and" follows,
                    // so "… and Bob runs" / "… and cats sleep" stay separate clauses.
                    let next_is_boundary = matches!(
                        self.tokens.get(self.current + 1).map(|t| &t.kind),
                        Some(TokenType::Period) | Some(TokenType::Comma) | Some(TokenType::And)
                            | Some(TokenType::EOF) | Some(TokenType::Exclamation) | None
                    );
                    let conjunct: Option<&'a LogicExpr<'a>> = match self.peek().kind {
                        TokenType::Adjective(a) | TokenType::NonIntersectiveAdjective(a) => {
                            self.advance();
                            Some(self.ctx.exprs.alloc(LogicExpr::Predicate {
                                name: a,
                                args: self.ctx.terms.alloc_slice([Term::Constant(subject.noun)]),
                                world: None,
                            }))
                        }
                        TokenType::Noun(a) if next_is_boundary => {
                            self.advance();
                            Some(self.ctx.exprs.alloc(LogicExpr::Predicate {
                                name: a,
                                args: self.ctx.terms.alloc_slice([Term::Constant(subject.noun)]),
                                world: None,
                            }))
                        }
                        _ if self.check_article() => match self.parse_noun_phrase(true) {
                            Ok(np) => {
                                Some(self.nominal_predication(Term::Constant(subject.noun), &np))
                            }
                            Err(_) => None,
                        },
                        _ => None,
                    };
                    match conjunct {
                        Some(c) => {
                            result = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                                left: result,
                                op: TokenType::And,
                                right: c,
                            });
                        }
                        None => {
                            self.current = save;
                            break;
                        }
                    }
                }

                // "is NOT a man" negates the whole nominal predication.
                let result = if is_negated {
                    &*self.ctx.exprs.alloc(LogicExpr::UnaryOp {
                        op: TokenType::Not,
                        operand: result,
                    })
                } else {
                    result
                };

                // Use the full NP so the SUBJECT's adjectives / PPs / possessor
                // survive — "X is the Y" must not drop them (e.g. "Ray Ricardo's
                // stamp is the Yellownose" keeps the genitive, "The red stamp is
                // the Yellownose" keeps "red"). Mirrors the enumerated-identity
                // (above) and adjective-complement (below) sites.
                return self.wrap_with_definiteness_full(&subject, result);
            }

            // After copula, prefer Adjective over simple-aspect Verb for ambiguous tokens
            // "is open" (Adj: state) is standard; "is open" (Verb: habitual) is ungrammatical here
            let prefer_adjective = if let TokenType::Ambiguous { primary, alternatives } = &self.peek().kind {
                let is_simple_verb = if let TokenType::Verb { aspect, .. } = **primary {
                    aspect == Aspect::Simple
                } else {
                    false
                };
                let has_adj_alt = alternatives.iter().any(|t| matches!(t, TokenType::Adjective(_)));
                is_simple_verb && has_adj_alt
            } else {
                false
            };

            if !prefer_adjective && self.check_verb() {
                let (verb, _verb_time, verb_aspect, verb_class) = self.consume_verb_with_metadata();

                // Stative verbs cannot be progressive
                if verb_class.is_stative() && verb_aspect == Aspect::Progressive {
                    return Err(ParseError {
                        kind: ParseErrorKind::StativeProgressiveConflict,
                        span: self.current_span(),
                    });
                }

                // Collect any prepositional phrases before "by" (for ditransitives)
                // "given to Mary by John" → goal = Mary, then agent = John
                let mut goal_args: Vec<Term<'a>> = Vec::new();
                while self.check_to_preposition() {
                    self.advance(); // consume "to"
                    let goal = self.parse_noun_phrase(true)?;
                    goal_args.push(self.noun_phrase_to_term(&goal));
                }

                // Check for passive: "was loved by John" or "was given to Mary by John"
                if self.check_by_preposition() {
                    self.advance(); // consume "by"
                    let agent = self.parse_noun_phrase(true)?;

                    // A DESCRIPTIVE by-agent ("the red team", "the Woodard family")
                    // becomes its own restrictor-carrying entity scoping the relation
                    // — `∃p(Restrictor(p) ∧ Verb(p, theme))` — instead of collapsing
                    // to the bare head. A bare agent keeps the constant form.
                    let (agent_term, agent_restr) = self.possessor_entity(&agent);
                    let mut args = vec![agent_term, self.noun_phrase_to_term(&subject)];
                    args.extend(goal_args);

                    let predicate = self.ctx.exprs.alloc(LogicExpr::Predicate {
                        name: verb,
                        args: self.ctx.terms.alloc_slice(args),
                        world: None,
                    });
                    let predicate = self.wrap_in_possessor_entity(agent_restr, predicate);

                    let with_time = if copula_time == Time::Past {
                        self.ctx.exprs.alloc(LogicExpr::Temporal {
                            operator: TemporalOperator::Past,
                            body: predicate,
                        })
                    } else {
                        predicate
                    };

                    return self.wrap_with_definiteness_full(&subject, with_time);
                }

                // Agentless passive: "The book was read" → ∃x.Read(x, Book)
                // For DEFINITE subjects ("The butler was caught"), use simpler reading
                // without existential over implicit agent: Past(catch(butler))
                // This makes negation cleaner for theorem proving: ¬Past(catch(butler))
                //
                // The existential-over-type reading is correct for a bare plural /
                // indefinite ("Drugs were approved", "A book was read") — a known
                // COMMON noun. A PROPER NAME ("Pluniden was approved") is a specific
                // referent, not a type, so it falls through to the constant path
                // below (which also carries trailing PP adjuncts and offsets).
                let subject_is_common_noun = {
                    let n = self.interner.resolve(subject.noun);
                    lexicon::lookup_noun_db(n).is_some()
                        || (n.ends_with('s')
                            && lexicon::lookup_noun_db(&n[..n.len() - 1]).is_some())
                };
                if copula_time == Time::Past && verb_aspect == Aspect::Simple
                    && subject.definiteness != Some(Definiteness::Definite)
                    && subject_is_common_noun {
                    // Indefinite agentless passive - treat as existential over implicit agent
                    let var_name = self.next_var_name();
                    let predicate = self.ctx.exprs.alloc(LogicExpr::Predicate {
                        name: verb,
                        args: self.ctx.terms.alloc_slice([
                            Term::Variable(var_name),
                            Term::Constant(subject.noun),
                        ]),
                        world: None,
                    });

                    let type_pred = self.ctx.exprs.alloc(LogicExpr::Predicate {
                        name: subject.noun,
                        args: self.ctx.terms.alloc_slice([Term::Variable(var_name)]),
                        world: None,
                    });

                    let temporal = self.ctx.exprs.alloc(LogicExpr::Temporal {
                        operator: TemporalOperator::Past,
                        body: predicate,
                    });

                    let body = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                        left: type_pred,
                        op: TokenType::And,
                        right: temporal,
                    });

                    let result = self.ctx.exprs.alloc(LogicExpr::Quantifier {
                        kind: QuantifierKind::Existential,
                        variable: var_name,
                        body,
                        island_id: self.current_island,
                    });

                    // Apply negation if "was not caught"
                    if is_negated {
                        return Ok(self.ctx.exprs.alloc(LogicExpr::UnaryOp {
                            op: TokenType::Not,
                            operand: result,
                        }));
                    }
                    return Ok(result);
                }

                // Check if verb is an intensional predicate (e.g., "rising", "changing")
                // Intensional predicates take intensions, not extensions
                let verb_str = self.interner.resolve(verb).to_lowercase();
                let subject_term = if lexicon::is_intensional_predicate(&verb_str) {
                    Term::Intension(subject.noun)
                } else {
                    Term::Constant(subject.noun)
                };

                let mut predicate: &'a LogicExpr<'a> = self.ctx.exprs.alloc(LogicExpr::Predicate {
                    name: verb,
                    args: self.ctx.terms.alloc_slice([subject_term]),
                    world: None,
                });

                // A PROGRESSIVE transitive ("is paying the rent", "is reading a
                // book", "is paying $700") takes a DIRECT OBJECT → Verb(subject,
                // object). A passive past-participle has none (its theme IS the
                // subject), so gate on Progressive. Not a preposition (that's a PP
                // adjunct, handled below) and not "by"/"to" (passive/dative above).
                if verb_aspect == Aspect::Progressive
                    && !self.check_preposition()
                    && (self.check_article() || self.check_number() || self.check_content_word())
                {
                    let obj_term = if self.check_number() {
                        *self.parse_measure_phrase()?
                    } else {
                        let obj_np = self.parse_noun_phrase(false)?;
                        self.noun_phrase_to_term(&obj_np)
                    };
                    predicate = self.ctx.exprs.alloc(LogicExpr::Predicate {
                        name: verb,
                        args: self.ctx.terms.alloc_slice([subject_term, obj_term]),
                        world: None,
                    });
                }

                // Trailing locative/temporal/material PP adjuncts on the passive ("was
                // taken on May 9", "was found in Spain", "was made OF rosewood") —
                // predicated of the theme (the subject). "of" after a passive participle
                // is the MATERIAL complement (Of(x, rosewood)), not a possessive.
                while self.check_preposition() {
                    let prep = match self.advance().kind {
                        TokenType::Preposition(s) => s,
                        _ => break,
                    };
                    let pp = if self.check_number() {
                        let m = self.parse_measure_phrase()?;
                        self.ctx.exprs.alloc(LogicExpr::Predicate {
                            name: prep,
                            args: self.ctx.terms.alloc_slice([subject_term, *m]),
                            world: None,
                        })
                    } else if self.check_content_word()
                        || matches!(self.peek().kind, TokenType::Article(_))
                    {
                        let obj = self.parse_noun_phrase(true)?;
                        self.ctx.exprs.alloc(LogicExpr::Predicate {
                            name: prep,
                            args: self.ctx.terms.alloc_slice([subject_term, Term::Constant(obj.noun)]),
                            world: None,
                        })
                    } else {
                        break;
                    };
                    predicate = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                        left: predicate,
                        op: TokenType::And,
                        right: pp,
                    });
                }

                // A trailing calendar-unit offset ("was taken 1 month after Y",
                // "was found 3 days before Z") relates the theme's temporal
                // position to a distinct standard — solver-ready, shared with the
                // active VP path.
                if let Some(constraint) = self.parse_temporal_offset_constraint(subject_term)? {
                    predicate = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                        left: predicate,
                        op: TokenType::And,
                        right: constraint,
                    });
                }
                // A bare temporal ordering ("was taken sometime before the photo of
                // the red panda", "was bought sometime before Faye's pet") relates
                // the theme to a distinct standard by time.
                else if let Some(constraint) = self.parse_bare_temporal_constraint(subject_term)? {
                    predicate = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                        left: predicate,
                        op: TokenType::And,
                        right: constraint,
                    });
                }

                // Manner adverbs after the participle ("was running quickly")
                // modify the event under the aspect operator.
                let adverbs = self.collect_adverbs();
                let predicate = if adverbs.is_empty() {
                    predicate
                } else {
                    self.ctx.exprs.alloc(LogicExpr::Event {
                        predicate,
                        adverbs: self.ctx.syms.alloc_slice(adverbs),
                    })
                };

                let with_aspect = if verb_aspect == Aspect::Progressive {
                    // Semelfactive + Progressive → Iterative
                    let operator = if verb_class == VerbClass::Semelfactive {
                        AspectOperator::Iterative
                    } else {
                        AspectOperator::Progressive
                    };
                    self.ctx.exprs.alloc(LogicExpr::Aspectual {
                        operator,
                        body: predicate,
                    })
                } else {
                    predicate
                };

                let with_time = if copula_time == Time::Past {
                    self.ctx.exprs.alloc(LogicExpr::Temporal {
                        operator: TemporalOperator::Past,
                        body: with_aspect,
                    })
                } else {
                    with_aspect
                };

                let final_expr = if is_negated {
                    self.ctx.exprs.alloc(LogicExpr::UnaryOp {
                        op: TokenType::Not,
                        operand: with_time,
                    })
                } else {
                    with_time
                };

                // For a BARE definite subject, return directly without the
                // Russellian wrapper: "The butler was caught" → Past(catch(butler)),
                // keeping the output simple for theorem proving. But a definite
                // subject WITH restrictions (adjectives, PPs like "at 40.5912 N",
                // a possessor) must go through the full wrapper so those
                // constraints survive — dropping them is meaning loss.
                if subject.definiteness == Some(Definiteness::Definite)
                    && subject.adjectives.is_empty()
                    && subject.pps.is_empty()
                    && subject.possessor.is_none()
                {
                    return Ok(final_expr);
                }

                return self.wrap_with_definiteness_full(&subject, final_expr);
            }

            // Handle relative clause with copula: "The book that John read is good."
            // The complement uses the same forms as a plain copula — proper-name
            // identity, "either A or B" disjunction, and (the)-NP predication —
            // predicated of the relative-clause variable, not just a bare adjective.
            if let Some((var_name, rel_clause)) = relative_clause {
                let var_term = Term::Variable(var_name);

                let main_pred: &'a LogicExpr<'a> = if self.check(&TokenType::Either) {
                    self.advance();
                    let np1 = self.parse_noun_phrase(true)?;
                    let p1 = self.nominal_predication_with_pps(var_term, &np1);
                    let p1 = self.conjoin_trailing_relative(p1, var_term)?;
                    if self.check(&TokenType::Or) {
                        self.advance();
                        let np2 = self.parse_noun_phrase(true)?;
                        let p2 = self.nominal_predication_with_pps(var_term, &np2);
                        let p2 = self.conjoin_trailing_relative(p2, var_term)?;
                        self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                            left: p1,
                            op: TokenType::Or,
                            right: p2,
                        })
                    } else {
                        p1
                    }
                } else if matches!(self.peek().kind, TokenType::ProperName(_))
                    && matches!(
                        self.tokens.get(self.current + 1).map(|t| &t.kind),
                        Some(TokenType::Possessive)
                    )
                {
                    // "is Kerry's project" — a possessive NP complement.
                    let np = self.parse_noun_phrase(true)?;
                    self.nominal_predication_with_pps(var_term, &np)
                } else if let TokenType::ProperName(pname) = self.peek().kind {
                    self.advance();
                    self.ctx.exprs.alloc(LogicExpr::Identity {
                        left: self.ctx.terms.alloc(var_term),
                        right: self.ctx.terms.alloc(Term::Constant(pname)),
                    })
                } else if self.check_article() {
                    let np = self.parse_noun_phrase(true)?;
                    let pred = self.nominal_predication_with_pps(var_term, &np);
                    self.conjoin_trailing_relative(pred, var_term)?
                } else if self.check_preposition() && !self.check_by_preposition() {
                    // PP predicate complement: "… is FROM Australia", "… is ON
                    // Holly Street", "… is AT 40 degrees" — predicated of the
                    // relativized variable. Mirrors the plain-copula PP path.
                    let prep_sym = match self.advance().kind {
                        TokenType::Preposition(s) => s,
                        _ => unreachable!("guarded by check_preposition()"),
                    };
                    if self.check_number() {
                        let measure = self.parse_measure_phrase()?;
                        self.ctx.exprs.alloc(LogicExpr::Predicate {
                            name: prep_sym,
                            args: self.ctx.terms.alloc_slice([var_term, *measure]),
                            world: None,
                        })
                    } else {
                        let obj = self.parse_noun_phrase(true)?;
                        self.ctx.exprs.alloc(LogicExpr::Predicate {
                            name: prep_sym,
                            args: self.ctx.terms.alloc_slice([var_term, Term::Constant(obj.noun)]),
                            world: None,
                        })
                    }
                } else {
                    let pred_word = self.consume_content_word()?;
                    self.ctx.exprs.alloc(LogicExpr::Predicate {
                        name: pred_word,
                        args: self.ctx.terms.alloc_slice([var_term]),
                        world: None,
                    })
                };
                let main_pred = if is_negated {
                    &*self.ctx.exprs.alloc(LogicExpr::UnaryOp {
                        op: TokenType::Not,
                        operand: main_pred,
                    })
                } else {
                    main_pred
                };

                let type_pred = self.ctx.exprs.alloc(LogicExpr::Predicate {
                    name: subject.noun,
                    args: self.ctx.terms.alloc_slice([Term::Variable(var_name)]),
                    world: None,
                });

                let inner = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                    left: type_pred,
                    op: TokenType::And,
                    right: rel_clause,
                });

                let body = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                    left: inner,
                    op: TokenType::And,
                    right: main_pred,
                });

                return Ok(self.ctx.exprs.alloc(LogicExpr::Quantifier {
                    kind: QuantifierKind::Existential,
                    variable: var_name,
                    body,
                    island_id: self.current_island,
                }));
            }

            // Note: is_negated was already set after copula consumption above

            // Possessive predicate with an elided noun: "The scent is Camille's." →
            // Possesses(Camille, scent) — the subject BELONGS to the named
            // possessor. Detected by a "'s" right after the name with no possessed
            // noun (a clause boundary follows); "X is Camille's perfume" (explicit
            // noun) falls through to the nominal-predicate paths.
            if let TokenType::ProperName(predicate_name) = self.peek().kind {
                let next_is_possessive = matches!(
                    self.tokens.get(self.current + 1).map(|t| &t.kind),
                    Some(TokenType::Possessive)
                );
                let elided = matches!(
                    self.tokens.get(self.current + 2).map(|t| &t.kind),
                    Some(TokenType::Period)
                        | Some(TokenType::EOF)
                        | Some(TokenType::Comma)
                        | Some(TokenType::And)
                        | Some(TokenType::Or)
                        | None
                );
                if next_is_possessive && elided {
                    self.advance(); // proper name
                    self.advance(); // "'s"
                    let poss = self.ctx.exprs.alloc(LogicExpr::Predicate {
                        name: self.interner.intern("Possesses"),
                        args: self.ctx.terms.alloc_slice([
                            Term::Constant(predicate_name),
                            Term::Constant(subject.noun),
                        ]),
                        world: None,
                    });
                    let result = if is_negated {
                        self.ctx.exprs.alloc(LogicExpr::UnaryOp {
                            op: TokenType::Not,
                            operand: poss,
                        })
                    } else {
                        poss
                    };
                    return self.wrap_with_definiteness_full(&subject, result);
                }
            }

            // Possessive NP predicate with an EXPLICIT noun: "The box is Kerry's
            // project" → Project(box) ∧ Possesses(Kerry, box). (The elided form "is
            // Camille's" is handled above; the bare identity below.)
            if matches!(self.peek().kind, TokenType::ProperName(_))
                && matches!(
                    self.tokens.get(self.current + 1).map(|t| &t.kind),
                    Some(TokenType::Possessive)
                )
            {
                let np = self.parse_noun_phrase(true)?;
                let pred = self.nominal_predication_with_pps(Term::Constant(subject.noun), &np);
                let result = if is_negated {
                    self.ctx.exprs.alloc(LogicExpr::UnaryOp {
                        op: TokenType::Not,
                        operand: pred,
                    })
                } else {
                    pred
                };
                return self.wrap_with_definiteness_full(&subject, result);
            }

            // Handle identity: "Clark is Superman" - NP copula ProperName → Identity
            // This enables Leibniz's Law: if Clark = Superman and mortal(Clark), then mortal(Superman)
            if let TokenType::ProperName(predicate_name) = self.peek().kind {
                self.advance(); // consume the proper name
                // Absorb subsequent capitalized words into one multi-word proper
                // name ("Porcher Place", "Highland Drive") so the identity does
                // not strand the second word.
                let predicate_name = self.absorb_multiword_proper_name(predicate_name);

                // Enumerated identity whose FIRST member is a proper name: "The four
                // people are Anthony, the waiter, the musician and the dentist." A
                // comma list (≥2 members) identifies the plural subject with the
                // group; members may be proper names OR definite descriptions. Mirrors
                // the common-noun-first enumerated-identity path above so a leading
                // proper name no longer strands the rest of the list.
                if self.check(&TokenType::Comma) {
                    let mut members: Vec<Term<'a>> = vec![Term::Constant(predicate_name)];
                    let mut member_rels: Vec<&'a LogicExpr<'a>> = Vec::new();
                    while self.check(&TokenType::Comma) || self.check(&TokenType::And) {
                        while self.check(&TokenType::Comma) || self.check(&TokenType::And) {
                            self.advance();
                        }
                        if let TokenType::ProperName(pn) = self.peek().kind {
                            self.advance();
                            let pn = self.absorb_multiword_proper_name(pn);
                            members.push(Term::Constant(pn));
                        } else if self.check_article() || self.check_content_word() {
                            let item = self.parse_noun_phrase(true)?;
                            members.push(Term::Constant(item.noun));
                            if let Some(rc) = self.try_attach_relative(Term::Constant(item.noun))? {
                                member_rels.push(rc);
                            }
                        } else {
                            break;
                        }
                    }
                    let group = Term::Group(self.ctx.terms.alloc_slice(members));
                    let identity: &'a LogicExpr<'a> = self.ctx.exprs.alloc(LogicExpr::Identity {
                        left: self.ctx.terms.alloc(Term::Constant(subject.noun)),
                        right: self.ctx.terms.alloc(group),
                    });
                    let mut result = if is_negated {
                        &*self.ctx.exprs.alloc(LogicExpr::UnaryOp {
                            op: TokenType::Not,
                            operand: identity,
                        })
                    } else {
                        identity
                    };
                    for rc in member_rels {
                        result = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                            left: result,
                            op: TokenType::And,
                            right: rc,
                        });
                    }
                    return self.wrap_with_definiteness_full(&subject, result);
                }

                let identity = self.ctx.exprs.alloc(LogicExpr::Identity {
                    left: self.ctx.terms.alloc(Term::Constant(subject.noun)),
                    right: self.ctx.terms.alloc(Term::Constant(predicate_name)),
                });
                let result = if is_negated {
                    self.ctx.exprs.alloc(LogicExpr::UnaryOp {
                        op: TokenType::Not,
                        operand: identity,
                    })
                } else {
                    identity
                };
                return self.wrap_with_definiteness_full(&subject, result);
            }

            // Handle "X is either A or B" — disjunctive predication in copula position.
            // "The dancer is either Tara or Bessie" → Tara(dancer) ∨ Bessie(dancer)
            if self.check(&TokenType::Either) {
                self.advance(); // consume "either"
                // Parse one disjunct: an NP optionally restricted by a relative
                // clause predicated of the subject ("the player who wore number
                // 29" → Player(Frank) ∧ ∃e(Wore(e) ∧ Agent(e, Frank) ∧ …)).
                let parse_disjunct = |p: &mut Self| -> ParseResult<&'a LogicExpr<'a>> {
                    // The copula is consumed, so a verb-word in the disjunct NP is a
                    // deverbal noun head ("either Leroy's PACK or the silver PACK").
                    let saved_ctx = p.nominal_np_context;
                    p.nominal_np_context = true;
                    let np_result = p.parse_noun_phrase(true);
                    p.nominal_np_context = saved_ctx;
                    let np = np_result?;
                    // nominal_predication keeps the disjunct NP's possessor and
                    // adjectives ("Elodie's perfume" → Perfume(x) ∧
                    // Possesses(Elodie, x)) — a bare Predicate would drop them and
                    // collapse "either A's perfume or B's perfume" to Perfume ∨
                    // Perfume (a vacuous, prover-useless disjunction).
                    let mut pred: &'a LogicExpr<'a> =
                        p.nominal_predication_with_pps(Term::Constant(subject.noun), &np);
                    if let Some(rel) = p.try_attach_relative(Term::Constant(subject.noun))? {
                        pred = p.ctx.exprs.alloc(LogicExpr::BinaryOp {
                            left: pred,
                            op: TokenType::And,
                            right: rel,
                        });
                    }
                    // A reduced relative on the disjunct ("either the mountain FIRST
                    // CLIMBED in 1845 or …") restricts the subject — the disjunct NP
                    // cannot be a main clause here.
                    if let Some(rr) = p.try_consume_reduced_relative(Term::Constant(subject.noun))? {
                        pred = p.ctx.exprs.alloc(LogicExpr::BinaryOp {
                            left: pred,
                            op: TokenType::And,
                            right: rr,
                        });
                    }
                    Ok(pred)
                };
                let pred1 = parse_disjunct(self)?;
                if self.check(&TokenType::Or) {
                    self.advance(); // consume "or"
                    let pred2 = parse_disjunct(self)?;
                    let disj = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                        left: pred1,
                        op: TokenType::Or,
                        right: pred2,
                    });
                    let with_time = if copula_time == Time::Past {
                        self.ctx.exprs.alloc(LogicExpr::Temporal {
                            operator: TemporalOperator::Past,
                            body: disj,
                        })
                    } else {
                        disj
                    };
                    let result = if is_negated {
                        self.ctx.exprs.alloc(LogicExpr::UnaryOp {
                            op: TokenType::Not,
                            operand: with_time,
                        })
                    } else {
                        with_time
                    };
                    // Full NP so the subject's adjectives / PPs / possessor survive
                    // ("the class with 15 people is either …" must keep the PP).
                    return self.wrap_with_definiteness_full(&subject, result);
                }
            }

            // Handle "X is from Y" / "X is on Y" — PP predicate in copula position.
            // Excludes "by" which is passive-agent and handled above.
            if self.check_preposition() && !self.check_by_preposition() {
                let prep_token = self.advance().clone();
                let prep_sym = match prep_token.kind {
                    TokenType::Preposition(s) => s,
                    _ => unreachable!("guarded by check_preposition()"),
                };
                // A numeric PP object is a measure ("is at 40.5912 N", "is at 385
                // degrees") — keep the amount and its unit/direction; otherwise an
                // ordinary NP object.
                let base = if self.check_number() {
                    let m = self.parse_measure_phrase()?;
                    self.ctx.exprs.alloc(LogicExpr::Predicate {
                        name: prep_sym,
                        args: self.ctx.terms.alloc_slice([Term::Constant(subject.noun), *m]),
                        world: None,
                    })
                } else {
                    // A copula + preposition rules out the matrix verb, so a
                    // verb-tagged head in the PP object is a deverbal noun ("was
                    // after the skydiving TRIP", "is from New Guinea").
                    let saved_ctx = self.nominal_np_context;
                    self.nominal_np_context = true;
                    let pp_obj_result = self.parse_noun_phrase(true);
                    self.nominal_np_context = saved_ctx;
                    let pp_obj = pp_obj_result?;
                    let pred: &'a LogicExpr<'a> = self.ctx.exprs.alloc(LogicExpr::Predicate {
                        name: prep_sym,
                        args: self.ctx.terms.alloc_slice([
                            Term::Constant(subject.noun),
                            Term::Constant(pp_obj.noun),
                        ]),
                        world: None,
                    });
                    // The PP object's own ADJECTIVES ("is on the BIG table" →
                    // On(x, Table) ∧ Big(Table)) and nested PPs survive via the shared
                    // helper, dropping them would be meaning loss.
                    self.attach_pp_object_modifiers(pred, &pp_obj)
                };
                // Disjunctive PP complement — "is in Florida OR in Maine" / "is in
                // A or B" → In(x,A) ∨ In(x,B): the domain-closure shape a logic-grid
                // bijection eliminates over ("not Florida ⇒ Maine"). "or in B"
                // repeats the preposition; "or B" reuses the first one.
                let mut base: &'a LogicExpr<'a> = base;
                while self.check(&TokenType::Or) {
                    let cp = self.checkpoint();
                    self.advance(); // "or"
                    let disj_prep = if self.check_preposition() && !self.check_by_preposition() {
                        match self.advance().kind {
                            TokenType::Preposition(s) => s,
                            _ => prep_sym,
                        }
                    } else {
                        prep_sym
                    };
                    if !(self.check_content_word()
                        || self.check_number()
                        || matches!(self.peek().kind, TokenType::Article(_)))
                    {
                        self.restore(cp);
                        break;
                    }
                    let saved_ctx = self.nominal_np_context;
                    self.nominal_np_context = true;
                    let disj_obj_res = self.parse_noun_phrase(true);
                    self.nominal_np_context = saved_ctx;
                    let disj_obj = disj_obj_res?;
                    let disj_pred: &'a LogicExpr<'a> = self.ctx.exprs.alloc(LogicExpr::Predicate {
                        name: disj_prep,
                        args: self
                            .ctx
                            .terms
                            .alloc_slice([Term::Constant(subject.noun), Term::Constant(disj_obj.noun)]),
                        world: None,
                    });
                    let disj_pred = self.attach_pp_object_modifiers(disj_pred, &disj_obj);
                    base = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                        left: base,
                        op: TokenType::Or,
                        right: disj_pred,
                    });
                }
                let with_time = if copula_time == Time::Past {
                    self.ctx.exprs.alloc(LogicExpr::Temporal {
                        operator: TemporalOperator::Past,
                        body: base,
                    })
                } else {
                    base
                };
                let result = if is_negated {
                    self.ctx.exprs.alloc(LogicExpr::UnaryOp {
                        op: TokenType::Not,
                        operand: with_time,
                    })
                } else {
                    with_time
                };
                // Use the full NP so a subject genitive ("The Alvarado family's
                // house is on Cora Street.") keeps its possession presupposition.
                return self.wrap_with_definiteness_full(&subject, result);
            }

            // Copula complement led by a temporal/ordinal adverb: "was FIRST", "is
            // NOW the leader". Shared with parse_predicate's copula path; wrapped here
            // with parse_atom's own tense / negation / definiteness.
            if let Some(base) =
                self.copula_temporal_adverb_complement(Term::Constant(subject.noun))?
            {
                let with_time = if copula_time == Time::Past {
                    self.ctx.exprs.alloc(LogicExpr::Temporal {
                        operator: TemporalOperator::Past,
                        body: base,
                    })
                } else {
                    base
                };
                let result = if is_negated {
                    self.ctx.exprs.alloc(LogicExpr::UnaryOp {
                        op: TokenType::Not,
                        operand: with_time,
                    })
                } else {
                    with_time
                };
                return self.wrap_with_definiteness_full(&subject, result);
            }

            // Handle "The king is bald" or "Alice is not guilty" - NP copula (not)? ADJ/NOUN
            // Also handles bare noun predicates like "Time is money"
            let predicate_name = self.consume_content_word()?;

            // Coordinated predicate adjectives — "is black and red" → Black(x) ∧
            // Red(x). The copula complement must consume the whole coordination;
            // otherwise "and red" is mis-parsed as a separate clause. Requires an
            // "and" before each extra adjective (a bare juxtaposed pair is left
            // alone — it may be a compound shade like "dark green").
            {
                let mut coord_adjs: Vec<Symbol> = vec![predicate_name];
                while self.check(&TokenType::And) {
                    let cp = self.checkpoint();
                    self.advance(); // "and"
                    if let TokenType::Adjective(a) = self.peek().kind {
                        // "and ADJ is/are/verb …" — ADJ is the SUBJECT of a new
                        // clause ("valid is high AND ready is high"), not a
                        // coordinated predicate adjective. Only a clause-final
                        // adjective ("is black AND red.") coordinates.
                        if matches!(
                            self.tokens.get(self.current + 1).map(|t| &t.kind),
                            Some(TokenType::Is) | Some(TokenType::Are)
                                | Some(TokenType::Was) | Some(TokenType::Were)
                                | Some(TokenType::Verb { .. })
                        ) {
                            self.restore(cp);
                            break;
                        }
                        self.advance();
                        coord_adjs.push(a);
                    } else {
                        self.restore(cp); // "and X" is not adjective coordination
                        break;
                    }
                }
                if coord_adjs.len() > 1 {
                    let mut conj: &'a LogicExpr<'a> = self.ctx.exprs.alloc(LogicExpr::Predicate {
                        name: coord_adjs[0],
                        args: self.ctx.terms.alloc_slice([Term::Constant(subject.noun)]),
                        world: None,
                    });
                    for &a in &coord_adjs[1..] {
                        let p = self.ctx.exprs.alloc(LogicExpr::Predicate {
                            name: a,
                            args: self.ctx.terms.alloc_slice([Term::Constant(subject.noun)]),
                            world: None,
                        });
                        conj = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                            left: conj,
                            op: TokenType::And,
                            right: p,
                        });
                    }
                    let conj = if is_negated {
                        self.ctx.exprs.alloc(LogicExpr::UnaryOp { op: TokenType::Not, operand: conj })
                    } else {
                        conj
                    };
                    let conj = if copula_time == Time::Past {
                        self.ctx.exprs.alloc(LogicExpr::Temporal {
                            operator: TemporalOperator::Past,
                            body: conj,
                        })
                    } else {
                        conj
                    };
                    return self.wrap_with_definiteness_full(&subject, conj);
                }
            }

            // A predicate adjective taking a POSTPOSED measure complement — "is
            // worth $26 billion", "is worth 5 dollars". The measure-BEFORE-adjective
            // form ("is 5 feet tall") is handled earlier; here the amount follows
            // the adjective and is its degree argument: Worth(subject, $26 billion).
            // A number after a predicate adjective is never a separate clause.
            if self.check_number() {
                let measure = self.parse_measure_phrase()?;
                let pred = self.ctx.exprs.alloc(LogicExpr::Predicate {
                    name: predicate_name,
                    args: self.ctx.terms.alloc_slice([Term::Constant(subject.noun), *measure]),
                    world: None,
                });
                let pred = if is_negated {
                    self.ctx.exprs.alloc(LogicExpr::UnaryOp { op: TokenType::Not, operand: pred })
                } else {
                    pred
                };
                let pred = if copula_time == Time::Past {
                    self.ctx.exprs.alloc(LogicExpr::Temporal {
                        operator: TemporalOperator::Past,
                        body: pred,
                    })
                } else {
                    pred
                };
                return self.wrap_with_definiteness_full(&subject, pred);
            }

            // Check for sort violation (metaphor detection)
            let subject_sort = lexicon::lookup_sort(self.interner.resolve(subject.noun));
            let predicate_str = self.interner.resolve(predicate_name);

            // Check ontology's predicate sort requirements (for adjectives like "happy")
            if let Some(s_sort) = subject_sort {
                if !crate::ontology::check_sort_compatibility(predicate_str, s_sort) {
                    let metaphor = self.ctx.exprs.alloc(LogicExpr::Metaphor {
                        tenor: self.ctx.terms.alloc(Term::Constant(subject.noun)),
                        vehicle: self.ctx.terms.alloc(Term::Constant(predicate_name)),
                    });
                    return self.wrap_with_definiteness_full(&subject, metaphor);
                }
            }

            // Check copular NP predicate sort compatibility (for "Time is money")
            let predicate_sort = lexicon::lookup_sort(predicate_str);
            if let (Some(s_sort), Some(p_sort)) = (subject_sort, predicate_sort) {
                if s_sort != p_sort && !s_sort.is_compatible_with(p_sort) && !p_sort.is_compatible_with(s_sort) {
                    let metaphor = self.ctx.exprs.alloc(LogicExpr::Metaphor {
                        tenor: self.ctx.terms.alloc(Term::Constant(subject.noun)),
                        vehicle: self.ctx.terms.alloc(Term::Constant(predicate_name)),
                    });
                    return self.wrap_with_definiteness_full(&subject, metaphor);
                }
            }

            // Bare gradable predication (§7.2) relies on a contextual standard: a
            // GRADABLE adjective ("tall", "heavy" — lexicon-tagged) is `∃d(Adj(x,d)
            // ∧ d > θ_C)`, exceeding a context standard θ_C, not a crisp predicate.
            let predicate = if self.pragmatic
                && crate::lexicon::is_gradable_adjective(
                    &self.interner.resolve(predicate_name).to_lowercase(),
                ) {
                let d = self.next_var_name();
                let theta = self.interner.intern("θ_C");
                let adj_d = self.ctx.exprs.alloc(LogicExpr::Predicate {
                    name: predicate_name,
                    args: self
                        .ctx
                        .terms
                        .alloc_slice([Term::Constant(subject.noun), Term::Variable(d)]),
                    world: None,
                });
                let exceeds = self.ctx.exprs.alloc(LogicExpr::Predicate {
                    name: self.interner.intern(">"),
                    args: self
                        .ctx
                        .terms
                        .alloc_slice([Term::Variable(d), Term::Constant(theta)]),
                    world: None,
                });
                let mut body = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                    left: adj_d,
                    op: TokenType::And,
                    right: exceeds,
                });
                // Vagueness (§8.5): a vague adjective's threshold has a PENUMBRA —
                // a borderline region — marked Borderline(θ_C). Sorites-susceptible.
                if crate::lexicon::is_vague_adjective(
                    &self.interner.resolve(predicate_name).to_lowercase(),
                ) {
                    let borderline = self.ctx.exprs.alloc(LogicExpr::Predicate {
                        name: self.interner.intern("Borderline"),
                        args: self.ctx.terms.alloc_slice([Term::Constant(theta)]),
                        world: None,
                    });
                    body = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                        left: body,
                        op: TokenType::And,
                        right: borderline,
                    });
                }
                self.ctx.exprs.alloc(LogicExpr::Quantifier {
                    kind: QuantifierKind::Existential,
                    variable: d,
                    body,
                    island_id: self.current_island,
                })
            } else {
                self.ctx.exprs.alloc(LogicExpr::Predicate {
                    name: predicate_name,
                    args: self.ctx.terms.alloc_slice([Term::Constant(subject.noun)]),
                    world: None,
                })
            };

            // Apply negation if "is not"
            let result = if is_negated {
                self.ctx.exprs.alloc(LogicExpr::UnaryOp {
                    op: TokenType::Not,
                    operand: predicate,
                })
            } else {
                predicate
            };

            // Apply temporal wrapper for "is always Y" → G(Y(X)) or "is never Y" → G(¬Y(X))
            let result = match copula_temporal {
                Some(CopulaTemporal::Always) => {
                    self.ctx.exprs.alloc(LogicExpr::Temporal {
                        operator: TemporalOperator::Always,
                        body: result,
                    })
                }
                Some(CopulaTemporal::Never) => {
                    let negated = self.ctx.exprs.alloc(LogicExpr::UnaryOp {
                        op: TokenType::Not,
                        operand: predicate,
                    });
                    self.ctx.exprs.alloc(LogicExpr::Temporal {
                        operator: TemporalOperator::Always,
                        body: negated,
                    })
                }
                Some(CopulaTemporal::Eventually) => {
                    self.ctx.exprs.alloc(LogicExpr::Temporal {
                        operator: TemporalOperator::Eventually,
                        body: result,
                    })
                }
                None => result,
            };

            // Use the full NP so the subject's adjectives/PPs are applied to the
            // restriction — copular predication must not drop them (e.g. the
            // adjective in "A red car is fast." → ∃x((Car(x) ∧ Red(x)) ∧ Fast(x))).
            return self.wrap_with_definiteness_full(&subject, result);
        }

        // "did" as a MAIN verb ("Philip did the dishes", "the diver did 49
        // previous jumps") — an Auxiliary(Past) followed by an object NP, not
        // do-support. parse_predicate_impl (verb.rs) already handles this; the
        // simple-clause path here did not, so proper-name-subject "did X"
        // stranded. (Object NPs only; "did not"/"did run" stay auxiliary.)
        if self.check_auxiliary_as_main_verb() {
            let subject_term = self.noun_phrase_to_term(&subject);
            let result = self.parse_do_as_main_verb(subject_term)?;
            return self.wrap_with_definiteness_full(&subject, result);
        }

        // Handle auxiliary: set pending_time, handle negation
        // BUT: "did it" should be parsed as verb "do" with object "it"
        // We lookahead to check if this is truly an auxiliary usage
        if self.check_auxiliary() && self.is_true_auxiliary_usage() {
            let aux_time = if let TokenType::Auxiliary(time) = self.advance().kind {
                time
            } else {
                Time::None
            };
            self.pending_time = Some(aux_time);

            // Handle negation: "John did not see dogs"
            if self.match_token(&[TokenType::Not]) {
                self.negative_depth += 1;

                // Skip "ever" if present: "John did not ever run"
                if self.check(&TokenType::Ever) {
                    self.advance();
                }

                // Presupposition trigger under negation: the presupposition PROJECTS
                // through the ¬ (Van der Sandt). "Mary does not regret lying." →
                // ¬Regret(Mary) [Presup: P(Lie(Mary))] — the lying survives.
                if self.check_presup_trigger()
                    && !self.is_followed_by_np_object()
                    && self.is_followed_by_gerund()
                {
                    let presup_kind = self.consume_presup_trigger();
                    self.negative_depth -= 1; // parse_presupposition handles the negation
                    return self.parse_presupposition(&subject, presup_kind, true);
                }

                // A bare verb the lexicon ALSO lists as a performative ("didn't ORDER")
                // is the clause's main verb after do-support, not a speech act — re-tag
                // it so check_verb consumes it (tense comes from the "did" auxiliary).
                if let TokenType::Performative(_) = self.peek().kind {
                    let lemma = self
                        .interner
                        .intern(&self.interner.resolve(self.peek().lexeme).to_lowercase());
                    self.tokens[self.current].kind = TokenType::Verb {
                        lemma,
                        time: Time::None,
                        aspect: Aspect::Simple,
                        class: crate::lexicon::VerbClass::Activity,
                    };
                }
                // Check for verb or "do" (TokenType::Do is separate from TokenType::Verb)
                if self.check_verb() || self.check(&TokenType::Do) {
                    let (verb, verb_time, verb_aspect, verb_class) =
                        if self.check(&TokenType::Do) {
                            self.advance(); // consume "do"
                            (
                                self.interner.intern("Do"),
                                Time::None,
                                Aspect::Simple,
                                crate::lexicon::VerbClass::Activity,
                            )
                        } else {
                            self.consume_verb_with_metadata()
                        };
                    let subject_term = self.noun_phrase_to_term(&subject);

                    // Check for NPI object first: "John did not see anything"
                    if self.check_npi_object() {
                        let npi_token = self.advance().kind.clone();
                        let obj_var = self.next_var_name();

                        let restriction_name = match npi_token {
                            TokenType::Anything => "Thing",
                            TokenType::Anyone => "Person",
                            _ => "Thing",
                        };

                        let restriction_sym = self.interner.intern(restriction_name);
                        let obj_restriction = self.ctx.exprs.alloc(LogicExpr::Predicate {
                            name: restriction_sym,
                            args: self.ctx.terms.alloc_slice([Term::Variable(obj_var)]),
                            world: None,
                        });

                        let verb_pred = self.ctx.exprs.alloc(LogicExpr::Predicate {
                            name: verb,
                            args: self.ctx.terms.alloc_slice([subject_term.clone(), Term::Variable(obj_var)]),
                            world: None,
                        });

                        let body = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                            left: obj_restriction,
                            op: TokenType::And,
                            right: verb_pred,
                        });

                        let quantified = self.ctx.exprs.alloc(LogicExpr::Quantifier {
                            kind: QuantifierKind::Existential,
                            variable: obj_var,
                            body,
                            island_id: self.current_island,
                        });

                        let effective_time = self.pending_time.take().unwrap_or(Time::None);
                        let with_time = match effective_time {
                            Time::Past => self.ctx.exprs.alloc(LogicExpr::Temporal {
                                operator: TemporalOperator::Past,
                                body: quantified,
                            }),
                            Time::Future => self.ctx.exprs.alloc(LogicExpr::Temporal {
                                operator: TemporalOperator::Future,
                                body: quantified,
                            }),
                            _ => quantified,
                        };

                        self.negative_depth -= 1;
                        return Ok(self.ctx.exprs.alloc(LogicExpr::UnaryOp {
                            op: TokenType::Not,
                            operand: with_time,
                        }));
                    }

                    // Check for quantifier object: "John did not see any dogs"
                    if self.check_quantifier() {
                        let quantifier_token = self.advance().kind.clone();
                        let object_np = self.parse_noun_phrase(false)?;
                        let obj_var = self.next_var_name();

                        let obj_restriction = self.ctx.exprs.alloc(LogicExpr::Predicate {
                            name: object_np.noun,
                            args: self.ctx.terms.alloc_slice([Term::Variable(obj_var)]),
                            world: None,
                        });

                        let verb_pred = self.ctx.exprs.alloc(LogicExpr::Predicate {
                            name: verb,
                            args: self.ctx.terms.alloc_slice([subject_term.clone(), Term::Variable(obj_var)]),
                            world: None,
                        });

                        let (kind, body) = match quantifier_token {
                            TokenType::Any => {
                                if self.is_negative_context() {
                                    (
                                        QuantifierKind::Existential,
                                        self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                                            left: obj_restriction,
                                            op: TokenType::And,
                                            right: verb_pred,
                                        }),
                                    )
                                } else {
                                    (
                                        QuantifierKind::Universal,
                                        self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                                            left: obj_restriction,
                                            op: TokenType::Implies,
                                            right: verb_pred,
                                        }),
                                    )
                                }
                            }
                            TokenType::Some => (
                                QuantifierKind::Existential,
                                self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                                    left: obj_restriction,
                                    op: TokenType::And,
                                    right: verb_pred,
                                }),
                            ),
                            TokenType::All => (
                                QuantifierKind::Universal,
                                self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                                    left: obj_restriction,
                                    op: TokenType::Implies,
                                    right: verb_pred,
                                }),
                            ),
                            _ => (
                                QuantifierKind::Existential,
                                self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                                    left: obj_restriction,
                                    op: TokenType::And,
                                    right: verb_pred,
                                }),
                            ),
                        };

                        let quantified = self.ctx.exprs.alloc(LogicExpr::Quantifier {
                            kind,
                            variable: obj_var,
                            body,
                            island_id: self.current_island,
                        });

                        let effective_time = self.pending_time.take().unwrap_or(Time::None);
                        let with_time = match effective_time {
                            Time::Past => self.ctx.exprs.alloc(LogicExpr::Temporal {
                                operator: TemporalOperator::Past,
                                body: quantified,
                            }),
                            Time::Future => self.ctx.exprs.alloc(LogicExpr::Temporal {
                                operator: TemporalOperator::Future,
                                body: quantified,
                            }),
                            _ => quantified,
                        };

                        self.negative_depth -= 1;
                        return Ok(self.ctx.exprs.alloc(LogicExpr::UnaryOp {
                            op: TokenType::Not,
                            operand: with_time,
                        }));
                    }

                    // A pronoun object ("did not do it") stays LITERAL, and the
                    // negation is returned UNWRAPPED. Resolving the pronoun or
                    // wrapping the definite subject in a uniqueness clause would
                    // desync a modus-tollens goal from the conditional antecedent it
                    // must refute ("if the butler did it …" keeps Theme(e, it)).
                    if self.check_pronoun() {
                        let pronoun_token = self.advance();
                        let pronoun_sym = pronoun_token.lexeme;
                        let roles = vec![
                            (ThematicRole::Agent, subject_term.clone()),
                            (ThematicRole::Theme, Term::Constant(pronoun_sym)),
                        ];
                        let effective_time = self.pending_time.take().unwrap_or(Time::None);
                        let mut modifiers: Vec<Symbol> = vec![];
                        match effective_time {
                            Time::Past => modifiers.push(self.interner.intern("Past")),
                            Time::Future => modifiers.push(self.interner.intern("Future")),
                            _ => {}
                        }
                        let event_var = self.get_event_var();
                        let suppress_existential = self.drs.in_conditional_antecedent();
                        let neo_event = self.ctx.exprs.alloc(LogicExpr::NeoEvent(Box::new(
                            NeoEventData {
                                event_var,
                                verb,
                                roles: self.ctx.roles.alloc_slice(roles),
                                modifiers: self.ctx.syms.alloc_slice(modifiers),
                                suppress_existential,
                                world: None,
                            },
                        )));
                        self.negative_depth -= 1;
                        return Ok(self.ctx.exprs.alloc(LogicExpr::UnaryOp {
                            op: TokenType::Not,
                            operand: neo_event,
                        }));
                    }

                    // The remaining complement forms (NP / measure / PP / aspect)
                    // fold through the shared finite-verb builder so "did not VERB …"
                    // folds exactly like the positive path; the auxiliary tense rides
                    // in via pending_time. The result is returned UNWRAPPED — a
                    // negated definite subject is not given a uniqueness clause here,
                    // keeping proof goals structurally clean.
                    let vp = self.build_verb_vp(
                        subject.noun,
                        subject_term,
                        false,
                        verb,
                        verb_time,
                        verb_aspect,
                        verb_class,
                    )?;

                    self.negative_depth -= 1;
                    return Ok(self.ctx.exprs.alloc(LogicExpr::UnaryOp {
                        op: TokenType::Not,
                        operand: vp,
                    }));
                }

                self.negative_depth -= 1;
            }
            // Non-negated auxiliary: pending_time is set, fall through to normal verb handling
        }

        // Check for presupposition triggers: "stopped", "started", "regrets", "knows"
        // Factive verbs like "know" only trigger presupposition with clausal complements
        // "John knows that..." → presupposition, "John knows Mary" → regular verb
        // Only trigger presupposition if followed by a gerund (e.g., "stopped smoking")
        // "John stopped." alone should parse as intransitive verb, not presupposition
        if self.check_presup_trigger() && !self.is_followed_by_np_object() && self.is_followed_by_gerund() {
            let presup_kind = self.consume_presup_trigger();
            return self.parse_presupposition(&subject, presup_kind, false);
        }

        // Handle bare plurals: "Birds fly." → Gen x. Bird(x) → Fly(x)
        let noun_str = self.interner.resolve(subject.noun);
        // Only a KNOWN plural common noun is a generic restrictor — an
        // unknown s-final proper name ("Opus flies.") is not a bare plural.
        let is_known_plural = {
            let lower = noun_str.to_lowercase();
            Self::is_plural_noun(noun_str)
                && (crate::lexicon::is_common_noun(&lower)
                    || matches!(
                        crate::lexicon::analyze_word(&lower),
                        Some(crate::lexicon::WordAnalysis::Noun(_))
                    ))
        };
        // GEN also covers do-negated characterizing sentences
        // ("Penguins do not fly."); the copular kind-predication case
        // ("Penguins are birds.") is intercepted at the copular dispatch.
        let generic_do_not = matches!(self.peek().kind, TokenType::Does | TokenType::Do)
            && matches!(
                self.tokens.get(self.current + 1).map(|t| &t.kind),
                Some(TokenType::Not)
            );
        let is_bare_plural = subject.definiteness.is_none()
            && subject.possessor.is_none()
            && is_known_plural
            && (self.check_verb() || generic_do_not);

        if is_bare_plural && generic_do_not {
            // "Penguins do not fly." → Gen x(Penguin(x) → ¬∃e(Fly(e) ∧ Agent(e, x))).
            // The nucleus is a real event so the generic matches what an
            // instance sentence ("Opus does not fly.") parses to.
            self.advance(); // do/does
            self.advance(); // not
            let var_name = self.next_var_name();
            let (verb, _t, _a, _) = self.consume_verb_with_metadata();
            let type_pred = self.ctx.exprs.alloc(LogicExpr::Predicate {
                name: subject.noun,
                args: self.ctx.terms.alloc_slice([Term::Variable(var_name)]),
                world: None,
            });
            let event_var = self.get_event_var();
            let verb_pred = self.ctx.exprs.alloc(LogicExpr::NeoEvent(Box::new(NeoEventData {
                event_var,
                verb,
                roles: self
                    .ctx
                    .roles
                    .alloc_slice(vec![(ThematicRole::Agent, Term::Variable(var_name))]),
                modifiers: self.ctx.syms.alloc_slice(vec![]),
                suppress_existential: false,
                world: None,
            })));
            let negated = self.ctx.exprs.alloc(LogicExpr::UnaryOp {
                op: TokenType::Not,
                operand: verb_pred,
            });
            let body = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                left: type_pred,
                op: TokenType::Implies,
                right: negated,
            });
            return Ok(self.ctx.exprs.alloc(LogicExpr::Quantifier {
                kind: QuantifierKind::Generic,
                variable: var_name,
                body,
                island_id: self.current_island,
            }));
        }

        if is_bare_plural {
            let var_name = self.next_var_name();
            let (verb, verb_time, verb_aspect, _) = self.consume_verb_with_metadata();

            let type_pred = self.ctx.exprs.alloc(LogicExpr::Predicate {
                name: subject.noun,
                args: self.ctx.terms.alloc_slice([Term::Variable(var_name)]),
                world: None,
            });

            // The generic nucleus is a real event — the same shape an
            // instance sentence parses to, so GEN defaults are derivable for
            // individuals ("Birds fly." + Bird(Tweety) ⊨~ Tweety flies).
            let mut roles = vec![(ThematicRole::Agent, Term::Variable(var_name))];
            if self.check_content_word() {
                let object = self.parse_noun_phrase(false)?;
                roles.push((ThematicRole::Theme, self.noun_phrase_to_term(&object)));
            }

            // A trailing manner adverb attaches to the generic nucleus's event
            // ("Dogs bark loudly." → Gen x(Dog(x) → ∃e(Bark(e) ∧ … ∧ Loudly(e)))),
            // the same event modifier an instance sentence produces.
            let manner_adverbs = self.collect_adverbs();

            let event_var = self.get_event_var();
            let verb_pred = self.ctx.exprs.alloc(LogicExpr::NeoEvent(Box::new(NeoEventData {
                event_var,
                verb,
                roles: self.ctx.roles.alloc_slice(roles),
                modifiers: self.ctx.syms.alloc_slice(manner_adverbs),
                suppress_existential: false,
                world: None,
            })));

            let effective_time = self.pending_time.take().unwrap_or(verb_time);
            let with_time = match effective_time {
                Time::Past => self.ctx.exprs.alloc(LogicExpr::Temporal {
                    operator: TemporalOperator::Past,
                    body: verb_pred,
                }),
                Time::Future => self.ctx.exprs.alloc(LogicExpr::Temporal {
                    operator: TemporalOperator::Future,
                    body: verb_pred,
                }),
                _ => verb_pred,
            };

            let with_aspect = if verb_aspect == Aspect::Progressive {
                self.ctx.exprs.alloc(LogicExpr::Aspectual {
                    operator: AspectOperator::Progressive,
                    body: with_time,
                })
            } else {
                with_time
            };

            let body = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                left: type_pred,
                op: TokenType::Implies,
                right: with_aspect,
            });

            return Ok(self.ctx.exprs.alloc(LogicExpr::Quantifier {
                kind: QuantifierKind::Generic,
                variable: var_name,
                body,
                island_id: self.current_island,
            }));
        }

        // Handle do-support: "John does not exist" or "John does run"
        if self.check(&TokenType::Does) || self.check(&TokenType::Do) {
            self.advance(); // consume does/do
            let is_negated = self.match_token(&[TokenType::Not]);

            // Presupposition trigger under do-support negation projects (Van der
            // Sandt): "Mary does not regret lying." → ¬Regret(Mary) [Presup: Lie(Mary)].
            if self.check_presup_trigger()
                && !self.is_followed_by_np_object()
                && self.is_followed_by_gerund()
            {
                let presup_kind = self.consume_presup_trigger();
                return self.parse_presupposition(&subject, presup_kind, is_negated);
            }

            if self.check_verb() {
                let (verb, verb_time, verb_aspect, verb_class) =
                    self.consume_verb_with_metadata();
                let verb_lemma = self.interner.resolve(verb).to_lowercase();

                // Check for embedded wh-clause with negation: "I don't know who"
                if self.check_wh_word() {
                    let wh_token = self.advance().kind.clone();
                    let is_who = matches!(wh_token, TokenType::Who);
                    let is_what = matches!(wh_token, TokenType::What);

                    let is_sluicing = self.is_at_end() ||
                        self.check(&TokenType::Period) ||
                        self.check(&TokenType::Comma);

                    if is_sluicing {
                        if let Some(template) = self.last_event_template.clone() {
                            let wh_var = self.next_var_name();
                            let subject_term = self.noun_phrase_to_term(&subject);

                            let roles: Vec<_> = if is_who {
                                std::iter::once((ThematicRole::Agent, Term::Variable(wh_var)))
                                    .chain(template.non_agent_roles.iter().cloned())
                                    .collect()
                            } else if is_what {
                                vec![
                                    (ThematicRole::Agent, subject_term.clone()),
                                    (ThematicRole::Theme, Term::Variable(wh_var)),
                                ]
                            } else {
                                std::iter::once((ThematicRole::Agent, Term::Variable(wh_var)))
                                    .chain(template.non_agent_roles.iter().cloned())
                                    .collect()
                            };

                            let event_var = self.get_event_var();
                            let suppress_existential = self.drs.in_conditional_antecedent();
                            if suppress_existential {
                                let event_class = self.interner.intern("Event");
                                self.drs.introduce_referent(event_var, event_class, Gender::Neuter, Number::Singular);
                            }
                            let reconstructed = self.ctx.exprs.alloc(LogicExpr::NeoEvent(Box::new(NeoEventData {
                                event_var,
                                verb: template.verb,
                                roles: self.ctx.roles.alloc_slice(roles),
                                modifiers: self.ctx.syms.alloc_slice(template.modifiers.clone()),
                                suppress_existential,
                                world: None,
                            })));

                            let question = self.ctx.exprs.alloc(LogicExpr::Question {
                                wh_variable: wh_var,
                                body: reconstructed,
                            });

                            let know_event_var = self.get_event_var();
                            let suppress_existential2 = self.drs.in_conditional_antecedent();
                            if suppress_existential2 {
                                let event_class = self.interner.intern("Event");
                                self.drs.introduce_referent(know_event_var, event_class, Gender::Neuter, Number::Singular);
                            }
                            let know_event = self.ctx.exprs.alloc(LogicExpr::NeoEvent(Box::new(NeoEventData {
                                event_var: know_event_var,
                                verb,
                                roles: self.ctx.roles.alloc_slice(vec![
                                    (ThematicRole::Agent, subject_term),
                                    (ThematicRole::Theme, Term::Proposition(question)),
                                ]),
                                modifiers: self.ctx.syms.alloc_slice(vec![]),
                                suppress_existential: suppress_existential2,
                                world: None,
                            })));

                            let result = if is_negated {
                                self.ctx.exprs.alloc(LogicExpr::UnaryOp {
                                    op: TokenType::Not,
                                    operand: know_event,
                                })
                            } else {
                                know_event
                            };

                            return self.wrap_with_definiteness_full(&subject, result);
                        }
                    }
                }

                // Special handling for "exist" with negation
                if verb_lemma == "exist" && is_negated {
                    // "The King of France does not exist" -> ¬∃x(KingOfFrance(x))
                    let var_name = self.next_var_name();
                    let restriction = self.ctx.exprs.alloc(LogicExpr::Predicate {
                        name: subject.noun,
                        args: self.ctx.terms.alloc_slice([Term::Variable(var_name)]),
                        world: None,
                    });
                    let exists = self.ctx.exprs.alloc(LogicExpr::Quantifier {
                        kind: QuantifierKind::Existential,
                        variable: var_name,
                        body: restriction,
                        island_id: self.current_island,
                    });
                    return Ok(self.ctx.exprs.alloc(LogicExpr::UnaryOp {
                        op: TokenType::Not,
                        operand: exists,
                    }));
                }

                // Regular do-support: "John does run" or "John does not run"
                // Also handles transitive: "John does not shave any man"
                let subject_term = self.noun_phrase_to_term(&subject);
                let modifiers: Vec<Symbol> = vec![];

                // Check for reflexive object
                if self.check(&TokenType::Reflexive) {
                    self.advance();
                    let roles = vec![
                        (ThematicRole::Agent, subject_term.clone()),
                        (ThematicRole::Theme, subject_term),
                    ];
                    let event_var = self.get_event_var();
                    let suppress_existential = self.drs.in_conditional_antecedent();
                    if suppress_existential {
                        let event_class = self.interner.intern("Event");
                        self.drs.introduce_referent(event_var, event_class, Gender::Neuter, Number::Singular);
                    }
                    let neo_event = self.ctx.exprs.alloc(LogicExpr::NeoEvent(Box::new(NeoEventData {
                        event_var,
                        verb,
                        roles: self.ctx.roles.alloc_slice(roles),
                        modifiers: self.ctx.syms.alloc_slice(modifiers),
                        suppress_existential,
                        world: None,
                    })));

                    let result = if is_negated {
                        self.ctx.exprs.alloc(LogicExpr::UnaryOp {
                            op: TokenType::Not,
                            operand: neo_event,
                        })
                    } else {
                        neo_event
                    };
                    return self.wrap_with_definiteness_full(&subject, result);
                }

                // Check for quantified object: "does not shave any man"
                if self.check_npi_quantifier() || self.check_quantifier() || self.check_article() {
                    let (obj_quantifier, was_definite_article) = if self.check_npi_quantifier() {
                        // "any" is an NPI quantifier in negative contexts
                        let tok = self.advance().kind.clone();
                        (Some(tok), false)
                    } else if self.check_quantifier() {
                        (Some(self.advance().kind.clone()), false)
                    } else {
                        let art = self.advance().kind.clone();
                        if let TokenType::Article(def) = art {
                            if def == Definiteness::Indefinite {
                                (Some(TokenType::Some), false)
                            } else {
                                (None, true)
                            }
                        } else {
                            (None, false)
                        }
                    };

                    let object_np = self.parse_noun_phrase(false)?;
                    let obj_var = self.next_var_name();

                    let mut type_pred: &'a LogicExpr<'a> = self.ctx.exprs.alloc(LogicExpr::Predicate {
                        name: object_np.noun,
                        args: self.ctx.terms.alloc_slice([Term::Variable(obj_var)]),
                        world: None,
                    });
                    // A quantified object's adjectives and PP restrictors ("has a
                    // RED book", "has a maximum range OF 475 ft") are part of the
                    // object's description — dropping them is a meaning-loss parse.
                    for &adj in object_np.adjectives {
                        let adj_pred = self.adjective_restriction(adj, obj_var, object_np.noun);
                        type_pred = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                            left: type_pred,
                            op: TokenType::And,
                            right: adj_pred,
                        });
                    }
                    for pp in object_np.pps {
                        let pp_sub = self.substitute_pp_placeholder(pp, obj_var);
                        type_pred = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                            left: type_pred,
                            op: TokenType::And,
                            right: pp_sub,
                        });
                    }

                    // Check for relative clause on object
                    let obj_restriction = if self.check(&TokenType::That) || self.check(&TokenType::Who) {
                        self.advance();
                        let rel_clause = self.parse_relative_clause(obj_var)?;
                        self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                            left: type_pred,
                            op: TokenType::And,
                            right: rel_clause,
                        })
                    } else {
                        type_pred
                    };

                    let event_var = self.get_event_var();
                    let suppress_existential = self.drs.in_conditional_antecedent();
                    if suppress_existential {
                        let event_class = self.interner.intern("Event");
                        self.drs.introduce_referent(event_var, event_class, Gender::Neuter, Number::Singular);
                    }

                    let roles = vec![
                        (ThematicRole::Agent, subject_term),
                        (ThematicRole::Theme, Term::Variable(obj_var)),
                    ];

                    let neo_event = self.ctx.exprs.alloc(LogicExpr::NeoEvent(Box::new(NeoEventData {
                        event_var,
                        verb,
                        roles: self.ctx.roles.alloc_slice(roles),
                        modifiers: self.ctx.syms.alloc_slice(modifiers),
                        suppress_existential,
                        world: None,
                    })));

                    // Build quantified expression
                    // For "does not shave any man" with negation + any:
                    // ¬∃x(Man(x) ∧ Shave(barber, x)) = "there is no man the barber shaves"
                    let quantifier_kind = match &obj_quantifier {
                        Some(TokenType::Any) if is_negated => QuantifierKind::Existential,
                        Some(TokenType::All) => QuantifierKind::Universal,
                        Some(TokenType::No) => QuantifierKind::Universal,
                        _ => QuantifierKind::Existential,
                    };

                    let obj_body = match &obj_quantifier {
                        Some(TokenType::All) => self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                            left: obj_restriction,
                            op: TokenType::Implies,
                            right: neo_event,
                        }),
                        Some(TokenType::No) => {
                            let neg = self.ctx.exprs.alloc(LogicExpr::UnaryOp {
                                op: TokenType::Not,
                                operand: neo_event,
                            });
                            self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                                left: obj_restriction,
                                op: TokenType::Implies,
                                right: neg,
                            })
                        }
                        _ => self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                            left: obj_restriction,
                            op: TokenType::And,
                            right: neo_event,
                        }),
                    };

                    let obj_quantified = self.ctx.exprs.alloc(LogicExpr::Quantifier {
                        kind: quantifier_kind,
                        variable: obj_var,
                        body: obj_body,
                        island_id: self.current_island,
                    });

                    // Apply negation at sentence level for "does not ... any"
                    let result = if is_negated && matches!(obj_quantifier, Some(TokenType::Any)) {
                        self.ctx.exprs.alloc(LogicExpr::UnaryOp {
                            op: TokenType::Not,
                            operand: obj_quantified,
                        })
                    } else if is_negated {
                        // For other quantifiers, negate the whole thing
                        self.ctx.exprs.alloc(LogicExpr::UnaryOp {
                            op: TokenType::Not,
                            operand: obj_quantified,
                        })
                    } else {
                        obj_quantified
                    };

                    return self.wrap_with_definiteness_full(&subject, result);
                }

                // Remaining complement forms — bare-noun object ("contain clove"),
                // measure/money ("cost $29.99", "measure 60 inches"), trailing PPs
                // ("happen in May", "go to Kansas"), aspect — are folded by the
                // shared finite-verb builder, exactly as in the positive path. The
                // negative scope stays open across the complement so NPIs inside it
                // are licensed; the result is wrapped in ¬ when "not" was present.
                if is_negated {
                    self.negative_depth += 1;
                }
                let vp = self.build_verb_vp(
                    subject.noun,
                    subject_term,
                    false,
                    verb,
                    verb_time,
                    verb_aspect,
                    verb_class,
                )?;
                if is_negated {
                    self.negative_depth -= 1;
                }
                // Returned UNWRAPPED: a definite subject is not given a uniqueness
                // clause here, keeping negated do-support goals structurally clean
                // for the proof engine (matches the pre-existing intransitive form).
                let result = if is_negated {
                    self.ctx.exprs.alloc(LogicExpr::UnaryOp {
                        op: TokenType::Not,
                        operand: vp,
                    })
                } else {
                    vp
                };
                return Ok(result);
            }
        }

        // Garden path detection: "The horse raced past the barn fell."
        // If we have a definite NP + past verb + more content + another verb,
        // try reduced relative interpretation
        // Skip if pending_time is set (auxiliary like "will" was just consumed)
        // Skip if verb is has/have/had (perfect aspect, not reduced relative)
        let is_perfect_aux = if self.check_verb() {
            let word = self.interner.resolve(self.peek().lexeme).to_lowercase();
            word == "has" || word == "have" || word == "had"
        } else {
            false
        };
        if subject.definiteness == Some(Definiteness::Definite) && self.check_verb() && self.pending_time.is_none() && !is_perfect_aux {
            let saved_pos = self.current;

            // Try parsing as reduced relative: first verb is modifier, look for main verb after
            if let Some(garden_path_result) = self.try_parse(|p| {
                let (modifier_verb, _modifier_time, _, _) = p.consume_verb_with_metadata();

                // Collect any PP modifiers on the reduced relative
                let mut pp_mods: Vec<&'a LogicExpr<'a>> = Vec::new();
                while p.check_preposition() {
                    let prep = if let TokenType::Preposition(prep) = p.advance().kind {
                        prep
                    } else {
                        break;
                    };
                    if p.check_article() || p.check_content_word() {
                        let pp_obj = p.parse_noun_phrase(false)?;
                        let pp_pred = p.ctx.exprs.alloc(LogicExpr::Predicate {
                            name: prep,
                            args: p.ctx.terms.alloc_slice([Term::Variable(p.interner.intern("x")), Term::Constant(pp_obj.noun)]),
                            world: None,
                        });
                        pp_mods.push(pp_pred);
                    }
                }

                // Now check if there's ANOTHER verb (the real main verb)
                if !p.check_verb() {
                    return Err(ParseError {
                        kind: ParseErrorKind::ExpectedVerb { found: p.peek().kind.clone() },
                        span: p.current_span(),
                    });
                }

                let (main_verb, main_time, _, _) = p.consume_verb_with_metadata();

                // Adjective complement of the main verb ("proved FALSE") is
                // its predicated result.
                let main_complement = if let TokenType::Adjective(a) = p.peek().kind {
                    p.advance();
                    Some(a)
                } else {
                    None
                };

                // The reanalysis must account for the WHOLE clause, or it is
                // not the right reading.
                if !p.at_clause_boundary() {
                    return Err(ParseError {
                        kind: ParseErrorKind::TrailingTokens {
                            found: p.peek().kind.clone(),
                        },
                        span: p.current_span(),
                    });
                }

                // Build: ∃x((Horse(x) ∧ ∀y(Horse(y) → y=x)) ∧ Raced(x) ∧ Past(x, Barn) ∧ Fell(x))
                let var = p.interner.intern("x");

                // Type predicate
                let type_pred = p.ctx.exprs.alloc(LogicExpr::Predicate {
                    name: subject.noun,
                    args: p.ctx.terms.alloc_slice([Term::Variable(var)]),
                    world: None,
                });

                // Modifier verb predicate (reduced relative)
                let mod_pred = p.ctx.exprs.alloc(LogicExpr::Predicate {
                    name: modifier_verb,
                    args: p.ctx.terms.alloc_slice([Term::Variable(var)]),
                    world: None,
                });

                // Main verb predicate
                let main_pred = p.ctx.exprs.alloc(LogicExpr::Predicate {
                    name: main_verb,
                    args: match main_complement {
                        Some(adj) => p
                            .ctx
                            .terms
                            .alloc_slice([Term::Variable(var), Term::Constant(adj)]),
                        None => p.ctx.terms.alloc_slice([Term::Variable(var)]),
                    },
                    world: None,
                });

                // Combine type + modifier
                let mut body = p.ctx.exprs.alloc(LogicExpr::BinaryOp {
                    left: type_pred,
                    op: TokenType::And,
                    right: mod_pred,
                });

                // Add PP modifiers
                for pp in pp_mods {
                    body = p.ctx.exprs.alloc(LogicExpr::BinaryOp {
                        left: body,
                        op: TokenType::And,
                        right: pp,
                    });
                }

                // Add main predicate
                body = p.ctx.exprs.alloc(LogicExpr::BinaryOp {
                    left: body,
                    op: TokenType::And,
                    right: main_pred,
                });

                // Wrap with temporal if needed
                let with_time = match main_time {
                    Time::Past => p.ctx.exprs.alloc(LogicExpr::Temporal {
                        operator: TemporalOperator::Past,
                        body,
                    }),
                    Time::Future => p.ctx.exprs.alloc(LogicExpr::Temporal {
                        operator: TemporalOperator::Future,
                        body,
                    }),
                    _ => body,
                };

                // Wrap in existential quantifier for definite
                Ok(p.ctx.exprs.alloc(LogicExpr::Quantifier {
                    kind: QuantifierKind::Existential,
                    variable: var,
                    body: with_time,
                    island_id: p.current_island,
                }))
            }) {
                return Ok(garden_path_result);
            }

            // Restore position if garden path didn't work
            self.current = saved_pos;
        }

        if self.check_modal() {
            return self.parse_aspect_chain(subject.noun);
        }

        // Handle "has/have/had" perfect aspect: "John has run"
        if self.check_content_word() {
            let word = self.interner.resolve(self.peek().lexeme).to_lowercase();
            if word == "has" || word == "have" || word == "had" {
                // Lookahead to distinguish perfect aspect ("has eaten") from possession ("has 3 children")
                let is_perfect_aspect = if self.current + 1 < self.tokens.len() {
                    let next_token = &self.tokens[self.current + 1].kind;
                    matches!(
                        next_token,
                        TokenType::Verb { .. } | TokenType::Not
                    ) && !matches!(next_token, TokenType::Number(_))
                } else {
                    false
                };
                if is_perfect_aspect {
                    return self.parse_aspect_chain(subject.noun);
                }
                // Otherwise fall through to verb parsing below
            }
        }

        // "John had RUN" is the past perfect; "Bob had THE PORT" (an object, no
        // participle) is possessive HAVE in the PAST — re-tag "had" as the verb so
        // the normal verb+object grammar builds ∃e(Have(e) ∧ Agent ∧ Theme ∧ Past)
        // instead of mis-reading "the port" as a perfect participle.
        if self.check(&TokenType::Had) {
            let next_is_participle = matches!(
                self.tokens.get(self.current + 1).map(|t| &t.kind),
                Some(TokenType::Verb { .. })
            );
            if next_is_participle {
                return self.parse_aspect_chain(subject.noun);
            }
            let have_lemma = self.interner.intern("Have");
            self.tokens[self.current].kind = TokenType::Verb {
                lemma: have_lemma,
                time: Time::Past,
                aspect: Aspect::Simple,
                class: VerbClass::State,
            };
            // fall through to the normal verb+object handling
        }

        // Handle "never" temporal negation: "John never runs"
        if self.check(&TokenType::Never) {
            self.advance();
            let verb = self.consume_verb();
            let subject_term = self.noun_phrase_to_term(&subject);

            // Optional object: quantified ("two requests") raises past the
            // negation; a plain NP fills Theme. Bare "never V" keeps the
            // classical ¬Verb(subject) shape.
            let mut object_quant: Option<(QuantifierKind, Symbol, Symbol)> = None;
            let mut object_term: Option<Term<'a>> = None;
            if let TokenType::Cardinal(n) = self.peek().kind {
                self.advance();
                let np = self.parse_noun_phrase(false)?;
                let var = self.next_var_name();
                object_quant = Some((QuantifierKind::Cardinal(n), var, np.noun));
                object_term = Some(Term::Variable(var));
            } else if matches!(self.peek().kind, TokenType::All | TokenType::Some) {
                let universal = matches!(self.advance().kind, TokenType::All);
                let np = self.parse_noun_phrase(false)?;
                let var = self.next_var_name();
                let kind = if universal {
                    QuantifierKind::Universal
                } else {
                    QuantifierKind::Existential
                };
                object_quant = Some((kind, var, np.noun));
                object_term = Some(Term::Variable(var));
            } else if self.check_content_word() || self.check_article() {
                let np = self.parse_noun_phrase(false)?;
                object_term = Some(self.noun_phrase_to_term(&np));
            }

            if object_term.is_none() {
                let verb_pred = self.ctx.exprs.alloc(LogicExpr::Predicate {
                    name: verb,
                    args: self.ctx.terms.alloc_slice([subject_term]),
                    world: None,
                });
                let result = self.ctx.exprs.alloc(LogicExpr::UnaryOp {
                    op: TokenType::Not,
                    operand: verb_pred,
                });
                return self.wrap_with_definiteness_full(&subject, result);
            }

            let mut roles = vec![(crate::ast::ThematicRole::Agent, subject_term)];
            if let Some(t) = object_term {
                roles.push((crate::ast::ThematicRole::Theme, t));
            }
            let modifiers = self.collect_adverbs();
            let event_var = self.get_event_var();
            let suppress_existential = self.drs.in_conditional_antecedent();
            let event = self.ctx.exprs.alloc(LogicExpr::NeoEvent(Box::new(NeoEventData {
                event_var,
                verb,
                roles: self.ctx.roles.alloc_slice(roles),
                modifiers: self.ctx.syms.alloc_slice(modifiers),
                suppress_existential,
                world: None,
            })));
            let mut result = self.ctx.exprs.alloc(LogicExpr::UnaryOp {
                op: TokenType::Not,
                operand: event,
            });
            if let Some((kind, var, noun)) = object_quant {
                let restriction = self.ctx.exprs.alloc(LogicExpr::Predicate {
                    name: noun,
                    args: self.ctx.terms.alloc_slice([Term::Variable(var)]),
                    world: None,
                });
                let connective = if matches!(kind, QuantifierKind::Universal) {
                    TokenType::Implies
                } else {
                    TokenType::And
                };
                let body = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                    left: restriction,
                    op: connective,
                    right: result,
                });
                result = self.ctx.exprs.alloc(LogicExpr::Quantifier {
                    kind,
                    variable: var,
                    body,
                    island_id: self.current_island,
                });
            }
            return self.wrap_with_definiteness_full(&subject, result);
        }

        // Adverbs of quantification ("usually", "often", "always", "generally", …)
        // before the verb mark a characterizing/habitual clause ("John usually
        // smokes."). Consume the adverb so the predicate parse proceeds; the
        // habitual operator falls out of the simple-present eventive reading. Only
        // consumed when a verb follows, so it never strands other constructions.
        if let TokenType::Adverb(sym)
        | TokenType::ScopalAdverb(sym)
        | TokenType::TemporalAdverb(sym) = self.peek().kind
        {
            // Adverbs of quantification are a lexical category (tagged in the
            // lexicon), not a hardcoded parser list.
            let w = self.interner.resolve(sym).to_lowercase();
            if crate::lexicon::is_quantificational_adverb(&w)
                && self.current + 1 < self.tokens.len()
                && matches!(self.tokens[self.current + 1].kind, TokenType::Verb { .. })
            {
                self.advance();
            }
        }

        if self.check_verb() {
            let (mut verb, verb_time, verb_aspect, verb_class) = self.consume_verb_with_metadata();

            // Check for verb sort violation (metaphor detection)
            let subject_sort = lexicon::lookup_sort(self.interner.resolve(subject.noun));
            let verb_str = self.interner.resolve(verb);
            if let Some(s_sort) = subject_sort {
                if !crate::ontology::check_sort_compatibility(verb_str, s_sort) {
                    let metaphor = self.ctx.exprs.alloc(LogicExpr::Metaphor {
                        tenor: self.ctx.terms.alloc(Term::Constant(subject.noun)),
                        vehicle: self.ctx.terms.alloc(Term::Constant(verb)),
                    });
                    return self.wrap_with_definiteness_full(&subject, metaphor);
                }
            }

            // Arithmetic / vague verbal comparative ("Tara scored 3 points lower
            // than Bessie"): the same construction parse_predicate_impl handles,
            // shared so a proper-name / definite subject parsed inline here keeps
            // the offset and the comparison instead of stranding the comparative.
            if let Some(cmp) =
                self.try_arithmetic_comparative(verb, Term::Constant(subject.noun), verb_time)?
            {
                return self.wrap_with_definiteness_full(&subject, cmp);
            }

            // Temporal offset ("Tara performed 2 weeks after Bessie").
            if let Some(off) =
                self.try_temporal_offset(verb, Term::Constant(subject.noun), verb_time)?
            {
                return self.wrap_with_definiteness_full(&subject, off);
            }

            // Ordinal-position offset ("finished 2 places ahead of Bob").
            if let Some(off) =
                self.try_positional_offset(verb, Term::Constant(subject.noun), verb_time)?
            {
                return self.wrap_with_definiteness_full(&subject, off);
            }

            // Raising / evidential verbs (seem, appear, look — tagged `Raising` in
            // the lexicon): "John seems happy." marks an evidence source; the
            // complement is NOT asserted but embedded under the evidential:
            // Seem(⟨Happy(John)⟩). So "seems happy" does not entail "happy". This is
            // checked BEFORE the control-verb path because seem/appear are raising
            // (subject-to-subject), not control, even if also tagged control.
            // The EVIDENTIAL use has a SMALL-CLAUSE complement: "seems happy",
            // "seems to be happy", "seems a fool". A bare intransitive ("a cat
            // appeared.") and a raising-to-control "seems to <verb>" ("seems to want
            // to stay") both fall through to the existing verb handling.
            let is_raising =
                crate::lexicon::is_raising_verb(&self.interner.resolve(verb).to_lowercase());
            let next_is_to_be = self.check(&TokenType::To)
                && self.current + 1 < self.tokens.len()
                && matches!(self.tokens[self.current + 1].kind, TokenType::Be);
            let raising_with_complement = is_raising
                && (matches!(self.peek().kind, TokenType::Adjective(_))
                    || next_is_to_be
                    || (self.check_content_word() && !self.check(&TokenType::To)));
            if raising_with_complement {
                // Optional "to be": "seems to be happy".
                if self.check(&TokenType::To) {
                    self.advance();
                    if self.check(&TokenType::Be) {
                        self.advance();
                    }
                }
                let complement = if let TokenType::Adjective(adj) = self.peek().kind {
                    self.advance();
                    self.ctx.exprs.alloc(LogicExpr::Predicate {
                        name: adj,
                        args: self.ctx.terms.alloc_slice([Term::Constant(subject.noun)]),
                        world: None,
                    })
                } else if self.check_content_word() {
                    self.parse_predicate_with_subject(subject.noun)?
                } else {
                    self.ctx.exprs.alloc(LogicExpr::Atom(self.interner.intern("?")))
                };
                let evidential = self.ctx.exprs.alloc(LogicExpr::Modal {
                    vector: crate::ast::ModalVector::new(
                        crate::ast::ModalDomain::Alethic,
                        1.0,
                        crate::ast::ModalFlavor::Evidential,
                    )
                    .with_base(verb),
                    operand: complement,
                });
                return self.wrap_with_definiteness_full(&subject, evidential);
            }

            // Perception complement (§3.2): a perception verb ("hear", "see" —
            // lexicon-tagged) takes an "NP bare-VP" small clause naming the PERCEIVED
            // EVENT: "Mary heard the bell ring." → Hear(Mary, ⟨Ring(bell)⟩). The bare
            // VP head is the LAST verb-capable token before the clause end (so the
            // perceived NP "the bell" is not greedily merged with "ring"); a clause
            // with no such trailing verb ("heard the bell") is an ordinary object.
            if crate::lexicon::is_perception_verb(&self.interner.resolve(verb).to_lowercase()) {
                let is_verb_capable = |kind: &TokenType| match kind {
                    TokenType::Verb { .. } => true,
                    TokenType::Ambiguous { primary, alternatives } => {
                        matches!(**primary, TokenType::Verb { .. })
                            || alternatives.iter().any(|t| matches!(t, TokenType::Verb { .. }))
                    }
                    _ => false,
                };
                let mut vp_idx = None;
                let mut i = self.current;
                while i < self.tokens.len() {
                    if matches!(
                        self.tokens[i].kind,
                        TokenType::Period | TokenType::EOF | TokenType::Comma
                    ) {
                        break;
                    }
                    // Verb-capable by token kind OR by lexicon (a word like "ring"
                    // may be tokenized as a noun after "the bell" yet head the VP).
                    let lex = self.interner.resolve(self.tokens[i].lexeme).to_lowercase();
                    if is_verb_capable(&self.tokens[i].kind)
                        || crate::lexicon::lookup_verb_db(&lex).is_some()
                    {
                        vp_idx = Some(i);
                    }
                    i += 1;
                }
                if let Some(vp_i) = vp_idx {
                    // The perceived subject is the noun/name immediately before the VP.
                    if vp_i > self.current {
                        let subj_kind = self.tokens[vp_i - 1].kind.clone();
                        let psubj = match subj_kind {
                            TokenType::Noun(n) | TokenType::ProperName(n) => Some(n),
                            // A function word cannot be the perceived subject.
                            TokenType::Article(_)
                            | TokenType::Preposition(_)
                            | TokenType::Period
                            | TokenType::Comma => None,
                            // An ADJECTIVE or NUMBER/CARDINAL before the candidate
                            // VP means this is NOT a small clause ("saw 6 previous
                            // JUMPS" — "previous" cannot be a clause subject); the
                            // verb-word is a deverbal noun head. Bail so the object
                            // NP path (counting NP / deverbal noun) handles it.
                            TokenType::Adjective(_)
                            | TokenType::NonIntersectiveAdjective(_)
                            | TokenType::Cardinal(_)
                            | TokenType::Number(_)
                            | TokenType::AtLeast(_)
                            | TokenType::AtMost(_) => None,
                            // A content word tokenized otherwise (e.g. a noun-or-verb
                            // ambiguity) — use its lexeme as the entity name.
                            _ => {
                                let lx = self
                                    .interner
                                    .resolve(self.tokens[vp_i - 1].lexeme)
                                    .to_lowercase();
                                let cap = lx
                                    .chars()
                                    .next()
                                    .map(|c| c.to_uppercase().collect::<String>() + &lx[1..])
                                    .unwrap_or(lx);
                                Some(self.interner.intern(&cap))
                            }
                        };
                        if let Some(psubj) = psubj {
                            let vlex = self.interner.resolve(self.tokens[vp_i].lexeme).to_lowercase();
                            let vname = vlex
                                .chars()
                                .next()
                                .map(|c| c.to_uppercase().collect::<String>() + &vlex[1..])
                                .unwrap_or(vlex);
                            let inner_verb = self.interner.intern(&vname);
                            self.current = vp_i + 1; // consume through the VP head
                            let perceived = self.ctx.exprs.alloc(LogicExpr::Predicate {
                                name: inner_verb,
                                args: self.ctx.terms.alloc_slice([Term::Constant(psubj)]),
                                world: None,
                            });
                            // A trailing adverb modifies the PERCEIVED event
                            // ("heard the bell ring LOUDLY").
                            let perceived_advs = self.collect_adverbs();
                            let perceived = if perceived_advs.is_empty() {
                                perceived
                            } else {
                                self.ctx.exprs.alloc(LogicExpr::Event {
                                    predicate: perceived,
                                    adverbs: self.ctx.syms.alloc_slice(perceived_advs),
                                })
                            };
                            let event_var = self.get_event_var();
                            let roles = vec![
                                (ThematicRole::Agent, Term::Constant(subject.noun)),
                                (ThematicRole::Theme, Term::Proposition(perceived)),
                            ];
                            let mut modifiers: Vec<Symbol> = Vec::new();
                            match verb_time {
                                Time::Past => modifiers.push(self.interner.intern("Past")),
                                Time::Future => modifiers.push(self.interner.intern("Future")),
                                _ => {}
                            }
                            let neo =
                                self.ctx.exprs.alloc(LogicExpr::NeoEvent(Box::new(NeoEventData {
                                    event_var,
                                    verb,
                                    roles: self.ctx.roles.alloc_slice(roles),
                                    modifiers: self.ctx.syms.alloc_slice(modifiers),
                                    suppress_existential: false,
                                    world: None,
                                })));
                            return self.wrap_with_definiteness_full(&subject, neo);
                        }
                    }
                }
            }

            // Check for control verb + infinitive (raising verbs handled above).
            // A SUBJECT-control verb only takes the control structure when an
            // infinitival complement actually follows ("started TO run"). Used as a
            // plain eventive verb ("The outing started at Greektown"), it falls
            // through to the regular VP grammar so its PP adjuncts attach. An
            // OBJECT-control verb keeps the control path even without an immediate
            // "to" — its object comes first ("persuaded Mary to be examined").
            if self.is_control_verb(verb)
                && (self.check_to()
                    || lexicon::is_object_control_verb(
                        &self.interner.resolve(verb).to_lowercase(),
                    ))
            {
                return self.parse_control_structure(&subject, verb, verb_time);
            }

            // If we have a relative clause, use variable binding
            if let Some((var_name, rel_clause)) = relative_clause {
                // A bare verb keeps the simple predication; material after it
                // ("The farmer who saw a cat CHASED IT.") takes the full VP
                // grammar over the relativized variable.
                let with_time = if self.at_clause_boundary() {
                    let main_pred = self.ctx.exprs.alloc(LogicExpr::Predicate {
                        name: verb,
                        args: self.ctx.terms.alloc_slice([Term::Variable(var_name)]),
                        world: None,
                    });

                    let effective_time = self.pending_time.take().unwrap_or(verb_time);
                    match effective_time {
                        Time::Past => &*self.ctx.exprs.alloc(LogicExpr::Temporal {
                            operator: TemporalOperator::Past,
                            body: main_pred,
                        }),
                        Time::Future => &*self.ctx.exprs.alloc(LogicExpr::Temporal {
                            operator: TemporalOperator::Future,
                            body: main_pred,
                        }),
                        _ => main_pred,
                    }
                } else {
                    self.current -= 1; // hand the verb back to the VP parser
                    self.parse_predicate_with_subject_as_var(var_name)?
                };

                // Build: ∃x(Type(x) ∧ RelClause(x) ∧ MainPred(x))
                let type_pred = self.ctx.exprs.alloc(LogicExpr::Predicate {
                    name: subject.noun,
                    args: self.ctx.terms.alloc_slice([Term::Variable(var_name)]),
                    world: None,
                });

                let inner = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                    left: type_pred,
                    op: TokenType::And,
                    right: rel_clause,
                });

                let body = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                    left: inner,
                    op: TokenType::And,
                    right: with_time,
                });

                return Ok(self.ctx.exprs.alloc(LogicExpr::Quantifier {
                    kind: QuantifierKind::Existential,
                    variable: var_name,
                    body,
                    island_id: self.current_island,
                }));
            }

            let subject_term = self.noun_phrase_to_term(&subject);
            let mut args = vec![subject_term.clone()];

            let unknown = self.interner.intern("?");

            // Check for embedded wh-clause: "I know who/what"
            if self.check_wh_word() {
                let wh_token = self.advance().kind.clone();

                // Determine wh-type for slot matching
                let is_who = matches!(wh_token, TokenType::Who);
                let is_what = matches!(wh_token, TokenType::What);

                // Check for sluicing: wh-word followed by terminator
                let is_sluicing = self.is_at_end() ||
                    self.check(&TokenType::Period) ||
                    self.check(&TokenType::Comma);

                if is_sluicing {
                    // Reconstruct from template
                    if let Some(template) = self.last_event_template.clone() {
                        let wh_var = self.next_var_name();

                        // Build roles with wh-variable in appropriate slot
                        let roles: Vec<_> = if is_who {
                            // "who" replaces Agent
                            std::iter::once((ThematicRole::Agent, Term::Variable(wh_var)))
                                .chain(template.non_agent_roles.iter().cloned())
                                .collect()
                        } else if is_what {
                            // "what" replaces Theme - use Agent from context, Theme is variable
                            vec![
                                (ThematicRole::Agent, subject_term.clone()),
                                (ThematicRole::Theme, Term::Variable(wh_var)),
                            ]
                        } else {
                            // Default: wh-variable as Agent
                            std::iter::once((ThematicRole::Agent, Term::Variable(wh_var)))
                                .chain(template.non_agent_roles.iter().cloned())
                                .collect()
                        };

                        let event_var = self.get_event_var();
                        let suppress_existential = self.drs.in_conditional_antecedent();
                        if suppress_existential {
                            let event_class = self.interner.intern("Event");
                            self.drs.introduce_referent(event_var, event_class, Gender::Neuter, Number::Singular);
                        }
                        let reconstructed = self.ctx.exprs.alloc(LogicExpr::NeoEvent(Box::new(NeoEventData {
                            event_var,
                            verb: template.verb,
                            roles: self.ctx.roles.alloc_slice(roles),
                            modifiers: self.ctx.syms.alloc_slice(template.modifiers.clone()),
                            suppress_existential,
                            world: None,
                        })));

                        let question = self.ctx.exprs.alloc(LogicExpr::Question {
                            wh_variable: wh_var,
                            body: reconstructed,
                        });

                        // Build: Know(subject, question)
                        let know_event_var = self.get_event_var();
                        let suppress_existential2 = self.drs.in_conditional_antecedent();
                        if suppress_existential2 {
                            let event_class = self.interner.intern("Event");
                            self.drs.introduce_referent(know_event_var, event_class, Gender::Neuter, Number::Singular);
                        }
                        let know_event = self.ctx.exprs.alloc(LogicExpr::NeoEvent(Box::new(NeoEventData {
                            event_var: know_event_var,
                            verb,
                            roles: self.ctx.roles.alloc_slice(vec![
                                (ThematicRole::Agent, subject_term),
                                (ThematicRole::Theme, Term::Proposition(question)),
                            ]),
                            modifiers: self.ctx.syms.alloc_slice(vec![]),
                            suppress_existential: suppress_existential2,
                            world: None,
                        })));

                        return self.wrap_with_definiteness_full(&subject, know_event);
                    }
                }

                // Non-sluicing embedded question: "I know who runs"
                let embedded = self.parse_embedded_wh_clause()?;
                let question = self.ctx.exprs.alloc(LogicExpr::Question {
                    wh_variable: self.interner.intern("x"),
                    body: embedded,
                });

                // Build: Know(subject, question)
                let know_event_var = self.get_event_var();
                let suppress_existential = self.drs.in_conditional_antecedent();
                if suppress_existential {
                    let event_class = self.interner.intern("Event");
                    self.drs.introduce_referent(know_event_var, event_class, Gender::Neuter, Number::Singular);
                }
                let know_event = self.ctx.exprs.alloc(LogicExpr::NeoEvent(Box::new(NeoEventData {
                    event_var: know_event_var,
                    verb,
                    roles: self.ctx.roles.alloc_slice(vec![
                        (ThematicRole::Agent, subject_term),
                        (ThematicRole::Theme, Term::Proposition(question)),
                    ]),
                    modifiers: self.ctx.syms.alloc_slice(vec![]),
                    suppress_existential,
                    world: None,
                })));

                return self.wrap_with_definiteness_full(&subject, know_event);
            }

            // Opaque attitude verbs take a finite clausal complement as a STRUCTURED
            // PROPOSITION (P3), not an extensional object: "John believes Mary left."
            // → Believe(John, ⟨Left(Mary)⟩). A pure-token lookahead detects an embedded
            // proper-name/pronoun subject directly followed by a verb (optionally after
            // the complementizer "that"); article-headed embedded clauses ("a spy
            // exists") keep their existing de re/de dicto treatment downstream.
            if crate::lexicon::is_opaque_verb(&self.interner.resolve(verb).to_lowercase()) {
                let mut i = self.current;
                if i < self.tokens.len() && matches!(self.tokens[i].kind, TokenType::That) {
                    i += 1;
                }
                let subj_ok = i < self.tokens.len()
                    && matches!(
                        self.tokens[i].kind,
                        TokenType::ProperName(_) | TokenType::Pronoun { .. }
                    );
                let verb_follows = subj_ok
                    && i + 1 < self.tokens.len()
                    && (matches!(
                        self.tokens[i + 1].kind,
                        TokenType::Verb { .. } | TokenType::Auxiliary(_)
                    )
                        // Noun/verb-ambiguous surface forms ("saw", "ring")
                        // tokenize as nouns; the irregular table identifies
                        // them as verb forms.
                        || crate::lexicon::lookup_irregular_verb(
                            &self
                                .interner
                                .resolve(self.tokens[i + 1].lexeme)
                                .to_lowercase(),
                        )
                        .is_some());
                if verb_follows {
                    if self.check(&TokenType::That) {
                        self.advance();
                    }
                    let embedded_subject = match self.peek().kind {
                        TokenType::ProperName(s) => {
                            self.advance();
                            s
                        }
                        TokenType::Pronoun { gender, number, .. } => {
                            self.advance();
                            match self.resolve_pronoun(gender, number)? {
                                ResolvedPronoun::Variable(s) | ResolvedPronoun::Constant(s) => s,
                            }
                        }
                        _ => unreachable!("guarded by subj_ok"),
                    };
                    let embedded_pred = self.parse_predicate_with_subject(embedded_subject)?;
                    let subject_term_for_event = self.coerce_agent(&subject);
                    let main_pred = self.ctx.exprs.alloc(LogicExpr::Predicate {
                        name: verb,
                        args: self.ctx.terms.alloc_slice([
                            subject_term_for_event,
                            Term::Proposition(embedded_pred),
                        ]),
                        world: None,
                    });
                    let effective_time = self.pending_time.take().unwrap_or(verb_time);
                    let with_time = match effective_time {
                        Time::Past => self.ctx.exprs.alloc(LogicExpr::Temporal {
                            operator: TemporalOperator::Past,
                            body: main_pred,
                        }),
                        Time::Future => self.ctx.exprs.alloc(LogicExpr::Temporal {
                            operator: TemporalOperator::Future,
                            body: main_pred,
                        }),
                        _ => main_pred,
                    };
                    return self.wrap_with_definiteness_full(&subject, with_time);
                }
            }

            let mut object_term: Option<Term<'a>> = None;
            // A definite/constant object's own adjectives and PP restrictors ("ate
            // the RED apple", "the frat ON Holly Street") — predicated of the
            // object term in the shared event build below; dropping them loses a
            // constraint (meaning-loss).
            let mut object_adjectives: &[Symbol] = &[];
            let mut object_desc_pps: &[&'a LogicExpr<'a>] = &[];
            // Secondary predication (§3.3): a post-object adjective ("painted the
            // door red", "ate the meat raw") captured during object parsing and
            // attached as a Result (change-of-state verb) or Depictive role below.
            let mut secondary_adj: Option<Symbol> = None;
            // Resultative vs depictive is a LEXICAL property of the verb (causative
            // change-of-state verbs are tagged `Resultative` in the lexicon).
            let secondary_role = |verb_lemma: &str| -> ThematicRole {
                if crate::lexicon::is_resultative_verb(verb_lemma) {
                    ThematicRole::Result
                } else {
                    ThematicRole::Depictive
                }
            };
            let mut second_object_term: Option<Term<'a>> = None;
            let mut object_superlative: Option<(Symbol, Symbol)> = None; // (adjective, noun)
            if self.check(&TokenType::Reflexive) {
                self.advance();
                let term = self.noun_phrase_to_term(&subject);
                object_term = Some(term.clone());
                args.push(term);

                // Check for distanced phrasal verb particle: "gave himself up"
                if let TokenType::Particle(particle_sym) = self.peek().kind {
                    let verb_str = self.interner.resolve(verb).to_lowercase();
                    let particle_str = self.interner.resolve(particle_sym).to_lowercase();
                    if let Some((phrasal_lemma, _class)) = crate::lexicon::lookup_phrasal_verb(&verb_str, &particle_str) {
                        self.advance();
                        verb = self.interner.intern(phrasal_lemma);
                    }
                }
            } else if self.check_pronoun() {
                let token = self.advance().clone();
                // See through an Ambiguous wrapper ("her" = object pronoun /
                // possessive): check_pronoun already ruled out the possessive
                // NP reading, so the primary pronoun analysis applies here.
                let pronoun_analysis = match &token.kind {
                    TokenType::Pronoun { gender, number, .. } => Some((*gender, *number)),
                    TokenType::Ambiguous { primary, .. } => match primary.as_ref() {
                        TokenType::Pronoun { gender, number, .. } => Some((*gender, *number)),
                        _ => None,
                    },
                    _ => None,
                };
                if let Some((gender, number)) = pronoun_analysis {
                    // Person deictics (§8.4) resolve to the discourse roles in ANY
                    // position: "Mary saw you." → Addressee, not a discourse referent.
                    let plex = self.interner.resolve(token.lexeme).to_lowercase();
                    let deictic_role = match plex.as_str() {
                        "you" | "yourself" => Some("Addressee"),
                        "i" | "me" | "myself" => Some("Speaker"),
                        _ => None,
                    };
                    if let Some(role) = deictic_role {
                        let term = Term::Constant(self.interner.intern(role));
                        object_term = Some(term.clone());
                        args.push(term);
                        // fall past the resolve-pronoun handling below
                    } else {
                    let resolved = self.resolve_pronoun(gender, number)?;
                    let resolved_sym = match resolved {
                        ResolvedPronoun::Variable(s) | ResolvedPronoun::Constant(s) => s,
                    };
                    // Binding Principle B: a plain (non-reflexive) object pronoun is
                    // free in its local clause — it must not corefer with the local
                    // subject. "John saw him." ⇒ him ≠ John. If resolution picked the
                    // subject, use a fresh distinct individual instead.
                    let term = if resolved_sym == subject.noun {
                        let deictic = match (gender, number) {
                            (Gender::Male, Number::Singular) => "Him",
                            (Gender::Female, Number::Singular) => "Her",
                            (Gender::Neuter, Number::Singular) => "It",
                            _ => "Them",
                        };
                        let sym = self.interner.intern(deictic);
                        self.drs.introduce_referent_with_source(
                            sym,
                            sym,
                            gender,
                            number,
                            crate::drs::ReferentSource::ProperName,
                        );
                        Term::Constant(sym)
                    } else {
                        match resolved {
                            ResolvedPronoun::Variable(s) => Term::Variable(s),
                            ResolvedPronoun::Constant(s) => Term::Constant(s),
                        }
                    };
                    object_term = Some(term.clone());
                    args.push(term);

                    // Check for distanced phrasal verb particle: "gave it up"
                    if let TokenType::Particle(particle_sym) = self.peek().kind {
                        let verb_str = self.interner.resolve(verb).to_lowercase();
                        let particle_str = self.interner.resolve(particle_sym).to_lowercase();
                        if let Some((phrasal_lemma, _class)) = crate::lexicon::lookup_phrasal_verb(&verb_str, &particle_str) {
                            self.advance();
                            verb = self.interner.intern(phrasal_lemma);
                        }
                    }
                    } // end non-deictic pronoun branch
                }
            } else if self.check(&TokenType::Either) {
                // "Tara danced either the hustle or the lindy." — disjunctive theme
                self.advance(); // consume "either"
                let np1 = self.parse_noun_phrase(true)?;
                if self.check(&TokenType::Or) {
                    self.advance(); // consume "or"
                    let np2 = self.parse_noun_phrase(true)?;

                    let effective_time = self.pending_time.take().unwrap_or(verb_time);
                    let subject_term1 = self.coerce_agent(&subject);
                    let subject_term2 = self.coerce_agent(&subject);
                    let suppress_existential = self.drs.in_conditional_antecedent();

                    let past_sym = self.interner.intern("Past");
                    let future_sym = self.interner.intern("Future");
                    let mut mods1 = vec![];
                    let mut mods2 = vec![];
                    match effective_time {
                        Time::Past => { mods1.push(past_sym); mods2.push(past_sym); }
                        Time::Future => { mods1.push(future_sym); mods2.push(future_sym); }
                        _ => {}
                    }

                    let event_var1 = self.get_event_var();
                    let event_var2 = self.get_event_var();

                    let neo1 = self.ctx.exprs.alloc(LogicExpr::NeoEvent(Box::new(NeoEventData {
                        event_var: event_var1,
                        verb,
                        roles: self.ctx.roles.alloc_slice(vec![
                            (ThematicRole::Agent, subject_term1),
                            (ThematicRole::Theme, Term::Constant(np1.noun)),
                        ]),
                        modifiers: self.ctx.syms.alloc_slice(mods1),
                        suppress_existential,
                        world: None,
                    })));
                    let neo2 = self.ctx.exprs.alloc(LogicExpr::NeoEvent(Box::new(NeoEventData {
                        event_var: event_var2,
                        verb,
                        roles: self.ctx.roles.alloc_slice(vec![
                            (ThematicRole::Agent, subject_term2),
                            (ThematicRole::Theme, Term::Constant(np2.noun)),
                        ]),
                        modifiers: self.ctx.syms.alloc_slice(mods2),
                        suppress_existential,
                        world: None,
                    })));

                    // Keep each disjunct object NP's possessor and PPs — "either
                    // the hustle from Spain or …" must not drop "from Spain";
                    // "either Tara's routine or …" must not drop the possessor.
                    let placeholder = self.interner.intern("_PP_SELF_");
                    let possesses = self.interner.intern("Possesses");
                    let mut augment = |p: &mut Self, neo: &'a LogicExpr<'a>, np: &crate::ast::NounPhrase<'a>| -> &'a LogicExpr<'a> {
                        let obj = Term::Constant(np.noun);
                        let mut e = neo;
                        if let Some(possessor) = np.possessor {
                            let poss = p.ctx.exprs.alloc(LogicExpr::Predicate {
                                name: possesses,
                                args: p
                                    .ctx
                                    .terms
                                    .alloc_slice([Term::Constant(possessor.noun), obj]),
                                world: None,
                            });
                            e = p.ctx.exprs.alloc(LogicExpr::BinaryOp {
                                left: e,
                                op: TokenType::And,
                                right: poss,
                            });
                        }
                        for pp in np.pps {
                            let pp_sub = match pp {
                                LogicExpr::Predicate { name, args, world } => {
                                    let new_args: Vec<Term<'a>> = args
                                        .iter()
                                        .map(|a| match a {
                                            Term::Variable(v) if *v == placeholder => obj,
                                            other => *other,
                                        })
                                        .collect();
                                    p.ctx.exprs.alloc(LogicExpr::Predicate {
                                        name: *name,
                                        args: p.ctx.terms.alloc_slice(new_args),
                                        world: *world,
                                    })
                                }
                                other => *other,
                            };
                            e = p.ctx.exprs.alloc(LogicExpr::BinaryOp {
                                left: e,
                                op: TokenType::And,
                                right: pp_sub,
                            });
                        }
                        e
                    };
                    let neo1 = augment(self, neo1, &np1);
                    let neo2 = augment(self, neo2, &np2);
                    let disj = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                        left: neo1,
                        op: TokenType::Or,
                        right: neo2,
                    });
                    return self.wrap_with_definiteness_full(&subject, disj);
                }
                return Err(ParseError {
                    kind: ParseErrorKind::UnexpectedToken {
                        expected: TokenType::Or,
                        found: self.peek().kind.clone(),
                    },
                    span: self.current_span(),
                });
            } else if self.counting_np_lookahead().is_some()
                || self.check_quantifier()
                || self.check_article()
                || self.check_possessive_pronoun()
            {
                // Quantified object: "John loves every woman" or "John saw a dog"
                let (obj_quantifier, was_definite_article) = if let Some(n) =
                    self.counting_np_lookahead()
                {
                    // A digit-led counting NP object ("saw 6 brown manatees"):
                    // consume the integer and quantify the remaining
                    // "(adjective)+ noun" as ∃=n, reusing the canonical
                    // quantified-object construction below. Without this the
                    // adjective is mis-read as a measure unit (→ a bogus
                    // Recipient role and a dropped count).
                    self.advance();
                    (Some(TokenType::Cardinal(n)), false)
                } else if self.check_possessive_pronoun() {
                    // Possessive NP object ("her dog"): parse_noun_phrase
                    // consumes the possessor; semantically definite.
                    (None, true)
                } else if self.check_quantifier() {
                    (Some(self.advance().kind.clone()), false)
                } else {
                    let art = self.advance().kind.clone();
                    if let TokenType::Article(def) = art {
                        if def == Definiteness::Indefinite {
                            (Some(TokenType::Some), false)
                        } else {
                            (None, true)  // Was a definite article
                        }
                    } else {
                        (None, false)
                    }
                };

                // The quantifier/article/cardinal just established this as an NP,
                // so a verb-word head after an adjective is a deverbal noun.
                self.nominal_np_context = true;
                let object_np_result = self.parse_noun_phrase(false);
                self.nominal_np_context = false;
                let object_np = object_np_result?;

                // Capture superlative info for constraint generation
                if let Some(adj) = object_np.superlative {
                    object_superlative = Some((adj, object_np.noun));
                }

                // Capture a post-object secondary-predicate adjective (consuming it).
                if let TokenType::Adjective(a) = self.peek().kind {
                    self.advance();
                    secondary_adj = Some(a);
                }

                // Check for distanced phrasal verb particle: "gave the book up"
                if let TokenType::Particle(particle_sym) = self.peek().kind {
                    let verb_str = self.interner.resolve(verb).to_lowercase();
                    let particle_str = self.interner.resolve(particle_sym).to_lowercase();
                    if let Some((phrasal_lemma, _class)) = crate::lexicon::lookup_phrasal_verb(&verb_str, &particle_str) {
                        self.advance(); // consume the particle
                        verb = self.interner.intern(phrasal_lemma);
                    }
                }

                if let Some(obj_q) = obj_quantifier {
                    // Check for opaque verb with indefinite object (de dicto reading)
                    // For verbs like "seek", "want", "believe" with indefinite objects,
                    // use Term::Intension to represent the intensional (concept) reading
                    let verb_str = self.interner.resolve(verb).to_lowercase();
                    let is_opaque = lexicon::lookup_verb_db(&verb_str)
                        .map(|meta| meta.features.contains(&lexicon::Feature::Opaque))
                        .unwrap_or(false);

                    // A finite verb after the NP makes it the subject of a
                    // CLAUSAL complement, not an object: "believes a spy
                    // exists" → Believe(s, ⟨∃y(Spy(y) ∧ Exist(y))⟩).
                    if is_opaque && self.check_verb() {
                        let emb_var = self.next_var_name();
                        let emb_restriction = self.ctx.exprs.alloc(LogicExpr::Predicate {
                            name: object_np.noun,
                            args: self.ctx.terms.alloc_slice([Term::Variable(emb_var)]),
                            world: None,
                        });
                        let emb_vp = self.parse_predicate_with_subject_as_var(emb_var)?;
                        let (emb_kind, emb_op) = match obj_q {
                            TokenType::All => (QuantifierKind::Universal, TokenType::Implies),
                            _ => (QuantifierKind::Existential, TokenType::And),
                        };
                        let emb_body = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                            left: emb_restriction,
                            op: emb_op,
                            right: emb_vp,
                        });
                        let embedded = self.ctx.exprs.alloc(LogicExpr::Quantifier {
                            kind: emb_kind,
                            variable: emb_var,
                            body: emb_body,
                            island_id: self.current_island,
                        });
                        let subject_term_for_event = self.coerce_agent(&subject);
                        let main_pred = self.ctx.exprs.alloc(LogicExpr::Predicate {
                            name: verb,
                            args: self.ctx.terms.alloc_slice([
                                subject_term_for_event,
                                Term::Proposition(embedded),
                            ]),
                            world: None,
                        });
                        let effective_time = self.pending_time.take().unwrap_or(verb_time);
                        let with_time = match effective_time {
                            Time::Past => self.ctx.exprs.alloc(LogicExpr::Temporal {
                                operator: TemporalOperator::Past,
                                body: main_pred,
                            }),
                            _ => main_pred,
                        };
                        return self.wrap_with_definiteness_full(&subject, with_time);
                    }

                    if is_opaque && matches!(obj_q, TokenType::Some) {
                        // De dicto reading: use Term::Intension for the theme
                        let intension_term = Term::Intension(object_np.noun);

                        // Register intensional entity for anaphora resolution
                        let event_var = self.get_event_var();
                        let mut modifiers = self.collect_adverbs();
                        let effective_time = self.pending_time.take().unwrap_or(verb_time);
                        match effective_time {
                            Time::Past => modifiers.push(self.interner.intern("Past")),
                            Time::Future => modifiers.push(self.interner.intern("Future")),
                            _ => {}
                        }

                        let subject_term_for_event = self.coerce_agent(&subject);
                        let roles = vec![
                            (ThematicRole::Agent, subject_term_for_event),
                            (ThematicRole::Theme, intension_term),
                        ];

                        let suppress_existential = self.drs.in_conditional_antecedent();
                        if suppress_existential {
                            let event_class = self.interner.intern("Event");
                            self.drs.introduce_referent(event_var, event_class, Gender::Neuter, Number::Singular);
                        }
                        let neo_event = self.ctx.exprs.alloc(LogicExpr::NeoEvent(Box::new(NeoEventData {
                            event_var,
                            verb,
                            roles: self.ctx.roles.alloc_slice(roles),
                            modifiers: self.ctx.syms.alloc_slice(modifiers),
                            suppress_existential,
                            world: None,
                        })));

                        return self.wrap_with_definiteness_full(&subject, neo_event);
                    }

                    let obj_var = self.next_var_name();

                    // Introduce object referent in DRS for cross-sentence anaphora
                    let obj_gender = Self::infer_noun_gender(self.interner.resolve(object_np.noun));
                    let obj_number = if Self::is_plural_noun(self.interner.resolve(object_np.noun)) {
                        Number::Plural
                    } else {
                        Number::Singular
                    };
                    // Definite descriptions presuppose existence, so they should be globally accessible
                    if object_np.definiteness == Some(Definiteness::Definite) {
                        self.drs.introduce_referent_with_source(obj_var, object_np.noun, obj_gender, obj_number, ReferentSource::MainClause);
                    } else {
                        self.drs.introduce_referent(obj_var, object_np.noun, obj_gender, obj_number);
                    }

                    let mut type_pred: &'a LogicExpr<'a> = self.ctx.exprs.alloc(LogicExpr::Predicate {
                        name: object_np.noun,
                        args: self.ctx.terms.alloc_slice([Term::Variable(obj_var)]),
                        world: None,
                    });

                    // Mass→count coercion (§6.2): a count determiner on a mass noun
                    // ("a water", "two waters") introduces a PORTION of the stuff:
                    // ∃x(Portion(x) ∧ Water(x) ∧ …). The mass noun itself stays
                    // non-atomic; the portion is the atom the determiner counts.
                    if crate::lexicon::is_mass_noun(&self.interner.resolve(object_np.noun).to_lowercase()) {
                        let portion_sym = self.interner.intern("Portion");
                        let portion_pred = self.ctx.exprs.alloc(LogicExpr::Predicate {
                            name: portion_sym,
                            args: self.ctx.terms.alloc_slice([Term::Variable(obj_var)]),
                            world: None,
                        });
                        type_pred = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                            left: portion_pred,
                            op: TokenType::And,
                            right: type_pred,
                        });
                    }

                    // Preserve the object's adjectives and PP restrictors ("has a
                    // RED book", "has a maximum range OF 475 ft") — the description
                    // is part of the object, and dropping it is a meaning-loss parse.
                    for &adj in object_np.adjectives {
                        let adj_pred = self.adjective_restriction(adj, obj_var, object_np.noun);
                        type_pred = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                            left: type_pred,
                            op: TokenType::And,
                            right: adj_pred,
                        });
                    }
                    for pp in object_np.pps {
                        let pp_sub = self.substitute_pp_placeholder(pp, obj_var);
                        type_pred = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                            left: type_pred,
                            op: TokenType::And,
                            right: pp_sub,
                        });
                    }

                    let obj_restriction = if self.check(&TokenType::That) || self.check(&TokenType::Who) {
                        self.advance();
                        let rel_clause = self.parse_relative_clause(obj_var)?;
                        self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                            left: type_pred,
                            op: TokenType::And,
                            right: rel_clause,
                        })
                    } else {
                        type_pred
                    };

                    // Continuations inside the object quantifier's scope: a
                    // recipient ("gave a book to Mary") or an object-control
                    // infinitive ("caused a fire to spread").
                    let mut recipient: Option<Term<'a>> = None;
                    let mut control_infinitive: Option<Symbol> = None;
                    if self.check_to_marker() {
                        let after_to = self.tokens.get(self.current + 1).map(|t| t.kind.clone());
                        match after_to {
                            Some(TokenType::Verb { lemma, .. }) => {
                                self.advance(); // to
                                self.advance(); // infinitive verb
                                control_infinitive = Some(lemma);
                            }
                            Some(TokenType::Noun(word))
                                if crate::lexicon::lookup_verb_db(
                                    &self.interner.resolve(word).to_lowercase(),
                                )
                                .is_some() =>
                            {
                                let lemma_str = crate::lexicon::lookup_verb_db(
                                    &self.interner.resolve(word).to_lowercase(),
                                )
                                .map(|m| m.lemma)
                                .unwrap();
                                self.advance(); // to
                                self.advance(); // infinitive verb (noun-classified)
                                control_infinitive = Some(self.interner.intern(lemma_str));
                            }
                            Some(kind)
                                if Lexer::is_ditransitive_verb(&self.interner.resolve(verb))
                                    && matches!(
                                        kind,
                                        TokenType::ProperName(_)
                                            | TokenType::Noun(_)
                                            | TokenType::Article(_)
                                    ) =>
                            {
                                self.advance(); // to
                                let r_np = self.parse_noun_phrase(false)?;
                                recipient = Some(Term::Constant(r_np.noun));
                            }
                            _ => {}
                        }
                    }

                    let event_var = self.get_event_var();
                    let mut modifiers = self.collect_adverbs();
                    let effective_time = self.pending_time.take().unwrap_or(verb_time);
                    match effective_time {
                        Time::Past => modifiers.push(self.interner.intern("Past")),
                        Time::Future => modifiers.push(self.interner.intern("Future")),
                        _ => {}
                    }

                    let subject_term_for_event = self.coerce_agent(&subject);
                    let mut roles = vec![
                        (ThematicRole::Agent, subject_term_for_event),
                        (ThematicRole::Theme, Term::Variable(obj_var)),
                    ];
                    if let Some(r) = recipient {
                        roles.push((ThematicRole::Recipient, r));
                    }

                    // Secondary predication over the (quantified) object variable.
                    if let Some(adj) = secondary_adj {
                        let sec_pred = self.ctx.exprs.alloc(LogicExpr::Predicate {
                            name: adj,
                            args: self.ctx.terms.alloc_slice([Term::Variable(obj_var)]),
                            world: None,
                        });
                        let role = secondary_role(&self.interner.resolve(verb).to_lowercase());
                        roles.push((role, Term::Proposition(sec_pred)));
                    }

                    // Capture template with object type for ellipsis reconstruction
                    // Use the object noun type instead of variable for reconstruction
                    let template_roles = vec![
                        (ThematicRole::Agent, subject_term_for_event),
                        (ThematicRole::Theme, Term::Constant(object_np.noun)),
                    ];
                    self.capture_event_template(verb, &template_roles, &modifiers);

                    let suppress_existential = self.drs.in_conditional_antecedent();
                    if suppress_existential {
                        let event_class = self.interner.intern("Event");
                        self.drs.introduce_referent(event_var, event_class, Gender::Neuter, Number::Singular);
                    }
                    let neo_event = if let Some(inf) = control_infinitive {
                        let inf_pred = self.ctx.exprs.alloc(LogicExpr::Predicate {
                            name: inf,
                            args: self.ctx.terms.alloc_slice([Term::Variable(obj_var)]),
                            world: None,
                        });
                        let control = self.ctx.exprs.alloc(LogicExpr::Control {
                            verb,
                            subject: self.ctx.terms.alloc(subject_term_for_event),
                            object: Some(&*self.ctx.terms.alloc(Term::Variable(obj_var))),
                            infinitive: inf_pred,
                        });
                        match effective_time {
                            Time::Past => &*self.ctx.exprs.alloc(LogicExpr::Temporal {
                                operator: TemporalOperator::Past,
                                body: control,
                            }),
                            Time::Future => &*self.ctx.exprs.alloc(LogicExpr::Temporal {
                                operator: TemporalOperator::Future,
                                body: control,
                            }),
                            _ => control,
                        }
                    } else {
                        let plain = &*self.ctx.exprs.alloc(LogicExpr::NeoEvent(Box::new(NeoEventData {
                            event_var,
                            verb,
                            roles: self.ctx.roles.alloc_slice(roles),
                            modifiers: self.ctx.syms.alloc_slice(modifiers),
                            suppress_existential,
                            world: None,
                        })));
                        // Trailing event-PP adjuncts ("takes a holiday WITH a friend
                        // TO some location") attach to the event INSIDE the object's
                        // existential scope — the definite-object path consumes these
                        // inline; without this they strand after an indefinite object.
                        self.attach_trailing_event_pps(plain, event_var)?
                    };

                    let obj_kind = match obj_q {
                        TokenType::All => QuantifierKind::Universal,
                        TokenType::Some => QuantifierKind::Existential,
                        TokenType::No => QuantifierKind::Universal,
                        TokenType::Most => QuantifierKind::Most,
                        TokenType::Few => QuantifierKind::Few,
                        TokenType::Many => QuantifierKind::Many,
                        TokenType::Cardinal(n) => QuantifierKind::Cardinal(n),
                        TokenType::AtLeast(n) => QuantifierKind::AtLeast(n),
                        TokenType::AtMost(n) => QuantifierKind::AtMost(n),
                        _ => QuantifierKind::Existential,
                    };

                    let obj_body = match obj_q {
                        TokenType::All => self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                            left: obj_restriction,
                            op: TokenType::Implies,
                            right: neo_event,
                        }),
                        TokenType::No => {
                            let neg = self.ctx.exprs.alloc(LogicExpr::UnaryOp {
                                op: TokenType::Not,
                                operand: neo_event,
                            });
                            self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                                left: obj_restriction,
                                op: TokenType::Implies,
                                right: neg,
                            })
                        }
                        _ => self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                            left: obj_restriction,
                            op: TokenType::And,
                            right: neo_event,
                        }),
                    };

                    // Wrap object with its quantifier
                    let obj_quantified = self.ctx.exprs.alloc(LogicExpr::Quantifier {
                        kind: obj_kind,
                        variable: obj_var,
                        body: obj_body,
                        island_id: self.current_island,
                    });

                    // A trailing temporal offset after an INDEFINITE/quantified
                    // object ("has a birthday 4 days before Rosemarie") — the
                    // constraint relates the SUBJECT's position to the standard's,
                    // so it conjoins OUTSIDE the object quantifier. Mirrors the
                    // constant-object temporal check; self-guards (no-op without
                    // an offset).
                    let obj_quantified = {
                        let subj = self.coerce_agent(&subject);
                        // A trailing temporal OFFSET ("4 days before X") or a BARE
                        // temporal ordering ("after Inez", "sometime before Guy") after
                        // the quantified object relates the SUBJECT to the standard, so
                        // it conjoins OUTSIDE the object quantifier. Without this, an
                        // indefinite object ("has an appointment after Inez") stranded
                        // the ordering. Both self-guard (no-op when absent).
                        let temporal = match self.parse_temporal_offset_constraint(subj)? {
                            Some(off) => Some(off),
                            None => self.parse_bare_temporal_constraint(subj)?,
                        };
                        match temporal {
                            Some(t) => self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                                left: obj_quantified,
                                op: TokenType::And,
                                right: t,
                            }),
                            None => obj_quantified,
                        }
                    };
                    // Now wrap the SUBJECT (don't skip it with early return!)
                    return self.wrap_with_definiteness_full(&subject, obj_quantified);
                } else {
                    // Definite object NP (e.g., "the house")
                    // Introduce to DRS for cross-sentence bridging anaphora
                    // E.g., "John entered the house. The door was open." - door bridges to house
                    // Note: was_definite_article is true because the article was consumed before parse_noun_phrase
                    if was_definite_article {
                        let obj_gender = Self::infer_noun_gender(self.interner.resolve(object_np.noun));
                        let obj_number = if Self::is_plural_noun(self.interner.resolve(object_np.noun)) {
                            Number::Plural
                        } else {
                            Number::Singular
                        };
                        // Definite descriptions presuppose existence, so they should be globally accessible
                        self.drs.introduce_referent_with_source(object_np.noun, object_np.noun, obj_gender, obj_number, ReferentSource::MainClause);
                    }

                    let term = self.noun_phrase_to_term(&object_np);
                    object_term = Some(term.clone());
                    object_adjectives = object_np.adjectives;
                    object_desc_pps = object_np.pps;
                    args.push(term);

                    // Ditransitive with a DEFINITE indirect object: "gave the
                    // winner the prize" — the definite IO took this non-quantified
                    // branch (a definite article carries no obj_quantifier), so the
                    // direct object must still be picked up here. The double-object
                    // builder below then assigns Recipient(IO) ∧ Theme(DO); without
                    // this the DO strands as a trailing token.
                    let verb_str = self.interner.resolve(verb);
                    if Lexer::is_ditransitive_verb(verb_str)
                        && (self.check_content_word() || self.check_article())
                    {
                        let second_np = self.parse_noun_phrase(false)?;
                        let second_term = Term::Constant(second_np.noun);
                        second_object_term = Some(second_term);
                        args.push(second_term);
                    }
                }
            } else if self.check_focus() {
                let focus_kind = if let TokenType::Focus(k) = self.advance().kind {
                    k
                } else {
                    FocusKind::Only
                };

                let event_var = self.get_event_var();
                let mut modifiers = self.collect_adverbs();
                let effective_time = self.pending_time.take().unwrap_or(verb_time);
                match effective_time {
                    Time::Past => modifiers.push(self.interner.intern("Past")),
                    Time::Future => modifiers.push(self.interner.intern("Future")),
                    _ => {}
                }

                let subject_term_for_event = self.coerce_agent(&subject);

                if self.check_preposition() {
                    let prep_token = self.advance().clone();
                    let prep_name = if let TokenType::Preposition(sym) = prep_token.kind {
                        sym
                    } else {
                        self.interner.intern("to")
                    };
                    let pp_obj = self.parse_noun_phrase(false)?;
                    let pp_obj_term = Term::Constant(pp_obj.noun);

                    let roles = vec![(ThematicRole::Agent, subject_term_for_event)];
                    let suppress_existential = self.drs.in_conditional_antecedent();
                    if suppress_existential {
                        let event_class = self.interner.intern("Event");
                        self.drs.introduce_referent(event_var, event_class, Gender::Neuter, Number::Singular);
                    }
                    let neo_event = self.ctx.exprs.alloc(LogicExpr::NeoEvent(Box::new(NeoEventData {
                        event_var,
                        verb,
                        roles: self.ctx.roles.alloc_slice(roles),
                        modifiers: self.ctx.syms.alloc_slice(modifiers),
                        suppress_existential,
                        world: None,
                    })));

                    let pp_pred = self.ctx.exprs.alloc(LogicExpr::Predicate {
                        name: prep_name,
                        args: self.ctx.terms.alloc_slice([Term::Variable(event_var), pp_obj_term]),
                        world: None,
                    });

                    let with_pp = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                        left: neo_event,
                        op: TokenType::And,
                        right: pp_pred,
                    });

                    let focused_ref = self.ctx.terms.alloc(pp_obj_term);
                    return Ok(self.ctx.exprs.alloc(LogicExpr::Focus {
                        kind: focus_kind,
                        focused: focused_ref,
                        scope: with_pp,
                    }));
                }

                let focused_np = self.parse_noun_phrase(false)?;
                let focused_term = self.noun_phrase_to_term(&focused_np);
                args.push(focused_term.clone());

                let roles = vec![
                    (ThematicRole::Agent, subject_term_for_event),
                    (ThematicRole::Theme, focused_term.clone()),
                ];

                let suppress_existential = self.drs.in_conditional_antecedent();
                if suppress_existential {
                    let event_class = self.interner.intern("Event");
                    self.drs.introduce_referent(event_var, event_class, Gender::Neuter, Number::Singular);
                }
                let neo_event = self.ctx.exprs.alloc(LogicExpr::NeoEvent(Box::new(NeoEventData {
                    event_var,
                    verb,
                    roles: self.ctx.roles.alloc_slice(roles),
                    modifiers: self.ctx.syms.alloc_slice(modifiers),
                    suppress_existential,
                    world: None,
                })));

                let focused_ref = self.ctx.terms.alloc(focused_term);
                return Ok(self.ctx.exprs.alloc(LogicExpr::Focus {
                    kind: focus_kind,
                    focused: focused_ref,
                    scope: neo_event,
                }));
            } else if self.check_number() {
                // Handle "has 3 children" or "has cardinality aleph_0"
                let measure = self.parse_measure_phrase()?;

                // If there's a noun after the measure (for "3 children" where
                // children wasn't a unit). An ARTICLE is NOT that noun — it begins
                // a rate denominator ("$700 A month", handled below) — so leave it.
                if self.check_content_word() && !self.check_article() {
                    let noun_sym = self.consume_content_word()?;
                    // Build: Has(Subject, 3, Children) where 3 is the count
                    let count_term = *measure;
                    object_term = Some(count_term.clone());
                    args.push(count_term);
                    second_object_term = Some(Term::Constant(noun_sym));
                    args.push(Term::Constant(noun_sym));
                } else {
                    // Just the measure: "has cardinality 5"
                    object_term = Some(*measure);
                    args.push(*measure);
                }
            } else if self.check_content_word() || self.check_article() {
                let object = self.parse_noun_phrase(false)?;
                if let Some(adj) = object.superlative {
                    object_superlative = Some((adj, object.noun));
                }

                // Collect all objects for potential "respectively" handling
                let mut all_objects: Vec<Symbol> = vec![object.noun];

                // Check for coordinated objects: "Tom and Jerry and Bob"
                while self.check(&TokenType::And) {
                    let saved = self.current;
                    self.advance(); // consume "and"
                    if self.check_content_word() || self.check_article() {
                        let next_obj = match self.parse_noun_phrase(false) {
                            Ok(np) => np,
                            Err(_) => {
                                self.current = saved;
                                break;
                            }
                        };
                        all_objects.push(next_obj.noun);
                    } else {
                        self.current = saved;
                        break;
                    }
                }

                // Check for "respectively" with single subject
                if self.check(&TokenType::Respectively) {
                    let respectively_span = self.peek().span;
                    // Single subject with multiple objects + respectively = error
                    if all_objects.len() > 1 {
                        return Err(ParseError {
                            kind: ParseErrorKind::RespectivelyLengthMismatch {
                                subject_count: 1,
                                object_count: all_objects.len(),
                            },
                            span: respectively_span,
                        });
                    }
                    // Single subject, single object + respectively is valid (trivially pairwise)
                    self.advance(); // consume "respectively"
                }

                // Use the first object (or only object) for normal processing
                let term = self.noun_phrase_to_term(&object);
                object_term = Some(term.clone());
                args.push(term.clone());

                // For multiple objects without "respectively", use group semantics
                if all_objects.len() > 1 {
                    let obj_members: Vec<Term<'a>> = all_objects.iter()
                        .map(|o| Term::Constant(*o))
                        .collect();
                    let obj_group = Term::Group(self.ctx.terms.alloc_slice(obj_members));
                    // Replace the single object with the group
                    args.pop();
                    args.push(obj_group);
                }

                // Check for distanced phrasal verb particle: "gave the book up"
                if let TokenType::Particle(particle_sym) = self.peek().kind {
                    let verb_str = self.interner.resolve(verb).to_lowercase();
                    let particle_str = self.interner.resolve(particle_sym).to_lowercase();
                    if let Some((phrasal_lemma, _class)) = crate::lexicon::lookup_phrasal_verb(&verb_str, &particle_str) {
                        self.advance(); // consume the particle
                        verb = self.interner.intern(phrasal_lemma);
                    }
                }

                // Check for "has cardinality aleph_0" pattern: noun followed by number
                if self.check_number() {
                    let measure = self.parse_measure_phrase()?;
                    second_object_term = Some(*measure);
                    args.push(*measure);
                }
                // Check for ditransitive: "John gave Mary a book"
                else {
                    let verb_str = self.interner.resolve(verb);
                    if Lexer::is_ditransitive_verb(verb_str) && (self.check_content_word() || self.check_article()) {
                        let second_np = self.parse_noun_phrase(false)?;
                        let second_term = self.noun_phrase_to_term(&second_np);
                        second_object_term = Some(second_term.clone());
                        args.push(second_term);
                    }
                }
            }

            let mut pp_predicates: Vec<&'a LogicExpr<'a>> = Vec::new();

            // Rate denominator after a MEASURE object ("$700 A month", "5 miles
            // PER hour", "$2.50 PER pound") → Per(event, unit), a solver-ready
            // rate. "a"/"an" or "per" + a CalendarUnit/unit-noun. Guarded to a
            // measure object so a bare "a <noun>" elsewhere is not a false rate.
            if matches!(object_term, Some(Term::Value { .. })) {
                let rate = self.check_preposition_is("per")
                    || (matches!(
                        self.peek().kind,
                        TokenType::Article(Definiteness::Indefinite)
                    ) && matches!(
                        self.tokens.get(self.current + 1).map(|t| &t.kind),
                        Some(TokenType::CalendarUnit(_)) | Some(TokenType::Noun(_))
                    ));
                if rate {
                    self.advance(); // "per" / "a"
                    let unit_lexeme = self.peek().lexeme;
                    self.advance(); // the unit
                    let unit_cap = {
                        let s = self.interner.resolve(unit_lexeme).to_string();
                        let mut c = s.chars();
                        match c.next() {
                            Some(f) => f.to_uppercase().collect::<String>() + c.as_str(),
                            None => s,
                        }
                    };
                    let event_sym = self.get_event_var();
                    pp_predicates.push(self.ctx.exprs.alloc(LogicExpr::Predicate {
                        name: self.interner.intern("Per"),
                        args: self.ctx.terms.alloc_slice([
                            Term::Variable(event_sym),
                            Term::Constant(self.interner.intern(&unit_cap)),
                        ]),
                        world: None,
                    }));
                }
            }

            while self.check_preposition() || self.check_to() {
                // "within N cycles" is a temporal bound, not a PP
                if self.check_preposition_is("within") && self.current + 1 < self.tokens.len()
                    && matches!(self.tokens[self.current + 1].kind, TokenType::Cardinal(_) | TokenType::Number(_))
                {
                    break;
                }
                let prep_token = self.advance().clone();
                let prep_name = if let TokenType::Preposition(sym) = prep_token.kind {
                    sym
                } else if matches!(prep_token.kind, TokenType::To) {
                    self.interner.intern("To")
                } else {
                    continue;
                };

                let pp_obj_term = if self.check(&TokenType::Reflexive) {
                    self.advance();
                    self.noun_phrase_to_term(&subject)
                } else if self.check_pronoun() {
                    let token = self.advance().clone();
                    if let TokenType::Pronoun { gender, number, .. } = token.kind {
                        let resolved = self.resolve_pronoun(gender, number)?;
                        match resolved {
                            ResolvedPronoun::Variable(s) => Term::Variable(s),
                            ResolvedPronoun::Constant(s) => Term::Constant(s),
                        }
                    } else {
                        continue;
                    }
                } else if self.check_content_word() || self.check_article() {
                    let prep_obj = self.parse_noun_phrase(false)?;
                    self.noun_phrase_to_term(&prep_obj)
                } else if self.check_number() {
                    // Numeric PP object ("sold for $105", "sell for $2.60").
                    *self.parse_measure_phrase()?
                } else if self.at_clause_boundary()
                    && crate::lexicon::is_particle(
                        &self.interner.resolve(prep_name).to_lowercase(),
                    )
                {
                    // A clause-final object-less PARTICLE preposition is an
                    // intransitive directional ("walked in", "sat down") — a
                    // lexically listed class; "of"/"to" cannot end a clause.
                    let event_sym = self.get_event_var();
                    pp_predicates.push(self.ctx.exprs.alloc(LogicExpr::Predicate {
                        name: prep_name,
                        args: self.ctx.terms.alloc_slice([Term::Variable(event_sym)]),
                        world: None,
                    }));
                    continue;
                } else {
                    // A mid-clause preposition with no object is not a PP —
                    // hand it back so the sentence-level parse reports it
                    // instead of silently dropping it.
                    self.current -= 1;
                    break;
                };

                if self.pp_attach_to_noun {
                    if let Some(ref obj) = object_term {
                        // NP-attachment: PP modifies the object noun
                        let pp_pred = self.ctx.exprs.alloc(LogicExpr::Predicate {
                            name: prep_name,
                            args: self.ctx.terms.alloc_slice([obj.clone(), pp_obj_term]),
                            world: None,
                        });
                        pp_predicates.push(pp_pred);
                    } else {
                        args.push(pp_obj_term);
                    }
                } else {
                    // VP-attachment: PP modifies the event (instrument/manner)
                    let event_sym = self.get_event_var();
                    let pp_pred = self.ctx.exprs.alloc(LogicExpr::Predicate {
                        name: prep_name,
                        args: self.ctx.terms.alloc_slice([Term::Variable(event_sym), pp_obj_term]),
                        world: None,
                    });
                    pp_predicates.push(pp_pred);
                }

                // Manner adverbs interleaved with PPs ("with a key quietly in
                // the house") modify the same event; absorbing them here lets
                // the loop continue to the next PP.
                for adv in self.collect_adverbs() {
                    let event_sym = self.get_event_var();
                    pp_predicates.push(self.ctx.exprs.alloc(LogicExpr::Predicate {
                        name: adv,
                        args: self.ctx.terms.alloc_slice([Term::Variable(event_sym)]),
                        world: None,
                    }));
                }
            }

            // Check for trailing relative clause on object NP: "the girl with the telescope that laughed"
            if self.check(&TokenType::That) || self.check(&TokenType::Who) {
                self.advance();
                let rel_var = self.next_var_name();
                let rel_pred = self.parse_relative_clause(rel_var)?;
                pp_predicates.push(rel_pred);
            }

            // A trailing temporal offset on the VP ("has a birthday 4 days before
            // Rosemarie", "set sail 2 years after Glenda") — N <unit> after/before
            // STANDARD relates the subject's position to the standard's
            // (solver-ready add/sub). It trails the object, so it is checked here
            // after the object/PP loop. A BARE ordering with no count ("won the prize
            // before the winner who won in chemistry", "graduated before Orlando")
            // takes the same slot — the indefinite-object path already chains both, so
            // the definite/possessive-object path (which falls through here) must too,
            // or the ordering strands (TrailingTokens at Before/After). Both
            // self-guard (return None without consuming unless the pattern matches).
            {
                let subj = self.coerce_agent(&subject);
                let off = match self.parse_temporal_offset_constraint(subj)? {
                    Some(o) => Some(o),
                    None => self.parse_bare_temporal_constraint(subj)?,
                };
                if let Some(off) = off {
                    pp_predicates.push(off);
                }
            }

            // Collect any trailing adverbs FIRST (before building NeoEvent)
            let mut modifiers = self.collect_adverbs();

            // Add temporal modifier as part of event semantics
            let effective_time = self.pending_time.take().unwrap_or(verb_time);
            match effective_time {
                Time::Past => modifiers.push(self.interner.intern("Past")),
                Time::Future => modifiers.push(self.interner.intern("Future")),
                _ => {}
            }

            // Add aspect modifier if applicable
            if verb_aspect == Aspect::Progressive {
                modifiers.push(self.interner.intern("Progressive"));
            } else if verb_aspect == Aspect::Perfect {
                modifiers.push(self.interner.intern("Perfect"));
            }

            // Build thematic roles for Neo-Davidsonian event semantics
            let mut roles: Vec<(ThematicRole, Term<'a>)> = Vec::new();

            // Check if verb is unaccusative (intransitive subject is Theme, not Agent)
            let verb_str_for_check = self.interner.resolve(verb).to_lowercase();
            let is_unaccusative = crate::lexicon::lookup_verb_db(&verb_str_for_check)
                .map(|meta| meta.features.contains(&crate::lexicon::Feature::Unaccusative))
                .unwrap_or(false);

            // Unaccusative verbs used intransitively: subject is Theme
            let has_object = object_term.is_some() || second_object_term.is_some();
            let subject_role = if is_unaccusative && !has_object {
                ThematicRole::Theme
            } else {
                ThematicRole::Agent
            };

            roles.push((subject_role, subject_term));
            if let Some(second_obj) = second_object_term {
                // Ditransitive: first object is Recipient, second is Theme
                if let Some(first_obj) = object_term {
                    roles.push((ThematicRole::Recipient, first_obj));
                }
                roles.push((ThematicRole::Theme, second_obj));
            } else if let Some(obj) = object_term {
                // Normal transitive: object is Theme
                roles.push((ThematicRole::Theme, obj));
            }

            // Secondary predication: attach the captured post-object adjective as a
            // Result/Depictive role over the object ("painted the door red").
            if let (Some(adj), Some(obj)) = (secondary_adj, object_term) {
                let sec_pred = self.ctx.exprs.alloc(LogicExpr::Predicate {
                    name: adj,
                    args: self.ctx.terms.alloc_slice([obj]),
                    world: None,
                });
                let role = secondary_role(&self.interner.resolve(verb).to_lowercase());
                roles.push((role, Term::Proposition(sec_pred)));
            }

            // Create event variable
            let event_var = self.get_event_var();

            // Capture template for ellipsis reconstruction before consuming roles
            self.capture_event_template(verb, &roles, &modifiers);

            // Create NeoEvent structure with all modifiers including time/aspect
            let suppress_existential = self.drs.in_conditional_antecedent();
            if suppress_existential {
                let event_class = self.interner.intern("Event");
                self.drs.introduce_referent(event_var, event_class, Gender::Neuter, Number::Singular);
            }
            let neo_event = self.ctx.exprs.alloc(LogicExpr::NeoEvent(Box::new(NeoEventData {
                event_var,
                verb,
                roles: self.ctx.roles.alloc_slice(roles),
                modifiers: self.ctx.syms.alloc_slice(modifiers),
                suppress_existential,
                world: None,
            })));

            // Combine with PP predicates if any
            let with_pps = if pp_predicates.is_empty() {
                neo_event
            } else {
                let mut combined = neo_event;
                for pp in pp_predicates {
                    combined = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                        left: combined,
                        op: TokenType::And,
                        right: pp,
                    });
                }
                combined
            };

            // Predicate a definite/constant object's adjectives + PP restrictors
            // of it ("ate the RED apple" → Red(Apple); "is the frat ON Holly
            // Street" → On(·, Holly Street)). Dropping them is meaning loss.
            let with_pps = if let Some(obj_term) = object_term {
                let placeholder = self.interner.intern("_PP_SELF_");
                let mut combined = with_pps;
                for &adj in object_adjectives {
                    let adj_pred = self.ctx.exprs.alloc(LogicExpr::Predicate {
                        name: adj,
                        args: self.ctx.terms.alloc_slice([obj_term]),
                        world: None,
                    });
                    combined = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                        left: combined,
                        op: TokenType::And,
                        right: adj_pred,
                    });
                }
                for pp in object_desc_pps {
                    if let LogicExpr::Predicate { name, args, world } = pp {
                        let new_args: Vec<Term<'a>> = args
                            .iter()
                            .map(|a| match a {
                                Term::Variable(v) if *v == placeholder => obj_term,
                                other => *other,
                            })
                            .collect();
                        let sub = self.ctx.exprs.alloc(LogicExpr::Predicate {
                            name: *name,
                            args: self.ctx.terms.alloc_slice(new_args),
                            world: *world,
                        });
                        combined = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                            left: combined,
                            op: TokenType::And,
                            right: sub,
                        });
                    }
                }
                combined
            } else {
                with_pps
            };

            // Apply aspectual operators based on verb class
            let with_aspect = if verb_aspect == Aspect::Progressive {
                // Semelfactive + Progressive → Iterative
                if verb_class == crate::lexicon::VerbClass::Semelfactive {
                    self.ctx.exprs.alloc(LogicExpr::Aspectual {
                        operator: AspectOperator::Iterative,
                        body: with_pps,
                    })
                } else {
                    // Other verbs + Progressive → Progressive
                    self.ctx.exprs.alloc(LogicExpr::Aspectual {
                        operator: AspectOperator::Progressive,
                        body: with_pps,
                    })
                }
            } else if verb_aspect == Aspect::Perfect {
                self.ctx.exprs.alloc(LogicExpr::Aspectual {
                    operator: AspectOperator::Perfect,
                    body: with_pps,
                })
            } else if effective_time == Time::Present && verb_aspect == Aspect::Simple {
                // Non-state verbs in simple present get Habitual reading
                if !verb_class.is_stative() {
                    self.ctx.exprs.alloc(LogicExpr::Aspectual {
                        operator: AspectOperator::Habitual,
                        body: with_pps,
                    })
                } else {
                    // State verbs in present: direct predication
                    with_pps
                }
            } else {
                with_pps
            };

            let with_adverbs = with_aspect;

            // Check for temporal anchor adverb at end of sentence
            let with_temporal = if self.check_temporal_adverb() {
                let anchor = if let TokenType::TemporalAdverb(adv) = self.advance().kind.clone() {
                    adv
                } else {
                    panic!("Expected temporal adverb");
                };
                self.ctx.exprs.alloc(LogicExpr::TemporalAnchor {
                    anchor,
                    body: with_adverbs,
                })
            } else {
                with_adverbs
            };

            let wrapped = self.wrap_with_definiteness_full(&subject, with_temporal)?;

            // Add superlative constraint for object NP if applicable
            if let Some((adj, noun)) = object_superlative {
                let superlative_expr = self.ctx.exprs.alloc(LogicExpr::Superlative {
                    adjective: adj,
                    subject: self.ctx.terms.alloc(Term::Constant(noun)),
                    domain: noun,
                });
                return Ok(self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                    left: wrapped,
                    op: TokenType::And,
                    right: superlative_expr,
                }));
            }

            return Ok(wrapped);
        }

        Ok(self.ctx.exprs.alloc(LogicExpr::Atom(subject.noun)))
    }

    fn check_preposition(&self) -> bool {
        matches!(self.peek().kind, TokenType::Preposition(_))
    }

    fn check_by_preposition(&self) -> bool {
        if let TokenType::Preposition(p) = self.peek().kind {
            p.is(self.interner, "by")
        } else {
            false
        }
    }

    fn check_preposition_is(&self, word: &str) -> bool {
        if let TokenType::Preposition(p) = self.peek().kind {
            p.is(self.interner, word)
        } else {
            false
        }
    }

    /// Check if current token is a word (noun/adj/verb lexeme) matching the given string
    fn check_word(&self, word: &str) -> bool {
        let token = self.peek();
        // A string/char LITERAL is a value, never a keyword — a `"not"` literal
        // must not be mistaken for the `not` operator (which the lexeme match
        // would otherwise do, breaking `Show "not".`).
        if matches!(token.kind, TokenType::StringLiteral(_) | TokenType::CharLiteral(_)) {
            return false;
        }
        let lexeme = self.interner.resolve(token.lexeme);
        lexeme.eq_ignore_ascii_case(word)
    }

    /// Like [`check_word`], but declines when the current token is a bound user
    /// variable — an English arithmetic operator word (`plus`, `times`, …) must
    /// yield to a variable of the same name (declarer-wins), so `Let times be 5`
    /// keeps `times` an identifier rather than the multiply operator.
    fn check_op_word(&self, word: &str) -> bool {
        self.check_word(word) && !self.user_bound.contains(&self.peek().lexeme)
    }

    fn peek_word_at(&self, offset: usize, word: &str) -> bool {
        if self.current + offset >= self.tokens.len() {
            return false;
        }
        let token = &self.tokens[self.current + offset];
        if matches!(token.kind, TokenType::StringLiteral(_) | TokenType::CharLiteral(_)) {
            return false;
        }
        let lexeme = self.interner.resolve(token.lexeme);
        lexeme.eq_ignore_ascii_case(word)
    }

    fn check_to_preposition(&self) -> bool {
        match self.peek().kind {
            TokenType::To => true,
            TokenType::Preposition(p) => p.is(self.interner, "to"),
            _ => false,
        }
    }

    fn check_content_word(&self) -> bool {
        match &self.peek().kind {
            TokenType::Noun(_)
            | TokenType::Adjective(_)
            | TokenType::NonIntersectiveAdjective(_)
            | TokenType::Verb { .. }
            | TokenType::ProperName(_)
            | TokenType::Article(_)
            // A quoted string in NL prose is a name ("the \"Yellownose\"").
            | TokenType::StringLiteral(_)
            // "May" the MONTH collides with the modal token; in a content-word
            // position ("in May", "on May 3") it is the month noun.
            | TokenType::May
            // A numeric literal heads/fills a noun position ("equal to 42",
            // "2001, 2002, … are years") — consume_content_word already returns it.
            | TokenType::Number(_)
            | TokenType::Performative(_) => true,
            // "item"/"items" are LOGOS collection-index keywords, but in
            // declarative NL prose they are ordinary nouns ("three different
            // items", "the item is red"). The lexer keeps the keyword tokens (so
            // imperative index syntax still lexes); the declarative parser reads
            // them as nouns here.
            TokenType::Item | TokenType::Items if self.mode == ParserMode::Declarative => true,
            // Calendar-unit words ("year", "day", "week") are common nouns in a
            // noun position ("four different years", "the year was 2001"); the
            // lexer tokenizes them as CalendarUnit for the temporal grammar.
            TokenType::CalendarUnit(_) if self.mode == ParserMode::Declarative => true,
            TokenType::Ambiguous { primary, alternatives } => {
                Self::is_content_word_type(primary)
                    || alternatives.iter().any(Self::is_content_word_type)
            }
            _ => false,
        }
    }

    fn is_content_word_type(t: &TokenType) -> bool {
        matches!(
            t,
            TokenType::Noun(_)
                | TokenType::Adjective(_)
                | TokenType::NonIntersectiveAdjective(_)
                | TokenType::Verb { .. }
                | TokenType::ProperName(_)
                | TokenType::Article(_)
                | TokenType::StringLiteral(_)
                | TokenType::Performative(_)
        )
    }

    /// Check for trailing "within N cycles" and wrap in BoundedEventually.
    pub(super) fn try_wrap_bounded_delay(&mut self, expr: &'a LogicExpr<'a>) -> &'a LogicExpr<'a> {
        if !self.check_preposition_is("within") {
            return expr;
        }
        let has_number = if self.current + 1 < self.tokens.len() {
            matches!(self.tokens[self.current + 1].kind, TokenType::Cardinal(_) | TokenType::Number(_))
        } else {
            false
        };
        if !has_number {
            return expr;
        }
        self.advance(); // consume "within"
        let bound = match self.advance().kind {
            TokenType::Cardinal(n) => n,
            TokenType::Number(sym) => {
                let n_str = self.interner.resolve(sym);
                n_str.parse::<u32>().unwrap_or(1)
            }
            _ => 1,
        };
        // Consume optional "cycle" / "cycles"
        if self.check_content_word() {
            let word = self.interner.resolve(self.peek().lexeme).to_lowercase();
            if word == "cycle" || word == "cycles" {
                self.advance();
            }
        }
        self.ctx.exprs.alloc(LogicExpr::Temporal {
            operator: TemporalOperator::BoundedEventually(bound),
            body: expr,
        })
    }

    /// Whether the preposition at the cursor introduces a CYCLE-temporal delay
    /// ("in the next cycle", "within 3 cycles", "after 2 cycles") rather than a
    /// locative/temporal PP adjunct. Such constructs are left for the SVA temporal
    /// wrappers (`try_wrap_next_cycle` / `try_wrap_within_cycles`), so the embedded
    /// VP parser's PP-adjunct loop must NOT swallow them.
    pub(super) fn pp_is_cycle_temporal(&self) -> bool {
        let prep = match &self.peek().kind {
            TokenType::Preposition(s) => self.interner.resolve(*s).to_lowercase(),
            _ => return false,
        };
        if !matches!(prep.as_str(), "in" | "within" | "after") {
            return false;
        }
        let mut i = self.current + 1;
        let end = (self.current + 5).min(self.tokens.len());
        while i < end {
            match &self.tokens[i].kind {
                TokenType::Period | TokenType::Comma | TokenType::EOF => return false,
                _ => {
                    let w = self.interner.resolve(self.tokens[i].lexeme).to_lowercase();
                    if matches!(w.as_str(), "cycle" | "cycles" | "tick" | "ticks") {
                        return true;
                    }
                }
            }
            i += 1;
        }
        false
    }

    /// Check for a trailing "next cycle" — both "in the next cycle" and the bare adverbial form
    /// "…grant is high next cycle." — and wrap in Temporal::Next.
    pub(super) fn try_wrap_next_cycle(&mut self, expr: &'a LogicExpr<'a>) -> &'a LogicExpr<'a> {
        // Bare "next cycle" (no preposition): "next" immediately followed by "cycle".
        let bare_next_cycle = self.interner.resolve(self.peek().lexeme).eq_ignore_ascii_case("next")
            && self
                .tokens
                .get(self.current + 1)
                .map(|t| self.interner.resolve(t.lexeme).eq_ignore_ascii_case("cycle"))
                .unwrap_or(false);
        if bare_next_cycle {
            self.advance(); // next
            self.advance(); // cycle
            return self.ctx.exprs.alloc(LogicExpr::Temporal {
                operator: TemporalOperator::Next,
                body: expr,
            });
        }
        if !self.check_preposition_is("in") {
            return expr;
        }
        // Lookahead: "in" (the)? next cycle — bail untouched otherwise.
        let mut i = self.current + 1;
        if matches!(self.tokens.get(i).map(|t| &t.kind), Some(TokenType::Article(_))) {
            i += 1;
        }
        let next_matches = self
            .tokens
            .get(i)
            .map(|t| self.interner.resolve(t.lexeme).eq_ignore_ascii_case("next"))
            .unwrap_or(false);
        let cycle_matches = self
            .tokens
            .get(i + 1)
            .map(|t| self.interner.resolve(t.lexeme).eq_ignore_ascii_case("cycle"))
            .unwrap_or(false);
        if !next_matches || !cycle_matches {
            return expr;
        }
        while self.current <= i + 1 {
            self.advance();
        }
        self.ctx.exprs.alloc(LogicExpr::Temporal {
            operator: TemporalOperator::Next,
            body: expr,
        })
    }

    fn check_verb(&self) -> bool {
        self.kind_is_verb(&self.peek().kind)
    }

    /// Verb-ness of an arbitrary token kind, mirroring `check_verb` so a look-ahead
    /// token (e.g. the participle after a leading adverb) is judged the same way the
    /// current token is — an `Ambiguous` token counts when a verb reading is live and
    /// noun-priority is off.
    fn kind_is_verb(&self, kind: &TokenType) -> bool {
        match kind {
            TokenType::Verb { .. } => true,
            TokenType::Ambiguous { primary, alternatives } => {
                if self.noun_priority_mode {
                    return false;
                }
                matches!(**primary, TokenType::Verb { .. })
                    || alternatives.iter().any(|t| matches!(t, TokenType::Verb { .. }))
            }
            _ => false,
        }
    }

    fn check_adverb(&self) -> bool {
        matches!(self.peek().kind, TokenType::Adverb(_))
    }

    fn check_performative(&self) -> bool {
        matches!(self.peek().kind, TokenType::Performative(_))
    }

    /// Resolve an optional direct object following a performative or its
    /// infinitival complement into a term. Deictic objects anchor to the
    /// discourse roles ("you" → Addressee, "me"/"myself" → Speaker); a proper
    /// name yields its constant. Returns `None` when no object NP follows.
    fn try_performative_object(&mut self) -> Option<Term<'a>> {
        match self.peek().kind {
            TokenType::Pronoun { .. } => {
                let text = self.interner.resolve(self.peek().lexeme).to_lowercase();
                let sym = match text.as_str() {
                    "you" => self.interner.intern("Addressee"),
                    "me" | "myself" => self.interner.intern("Speaker"),
                    other => {
                        let cap = other
                            .chars()
                            .next()
                            .map(|c| c.to_uppercase().collect::<String>() + &other[1..])
                            .unwrap_or_default();
                        self.interner.intern(&cap)
                    }
                };
                self.advance();
                Some(Term::Constant(sym))
            }
            TokenType::ProperName(s) => {
                self.advance();
                Some(Term::Constant(s))
            }
            _ => None,
        }
    }

    /// Build the complement predicate `verb(subject [, object])` for a
    /// performative, capturing an optional direct object. Used both for the
    /// infinitival complement ("promise to call you" → `Call(speaker, hearer)`)
    /// and for the bare performative act ("thank you" → `Thank(speaker, hearer)`).
    fn performative_predicate(&mut self, verb: Symbol, subject: Symbol) -> &'a LogicExpr<'a> {
        if let Some(obj) = self.try_performative_object() {
            self.ctx.exprs.alloc(LogicExpr::Predicate {
                name: verb,
                args: self.ctx.terms.alloc_slice([Term::Constant(subject), obj]),
                world: None,
            })
        } else {
            self.ctx.exprs.alloc(LogicExpr::Predicate {
                name: verb,
                args: self.ctx.terms.alloc_slice([Term::Constant(subject)]),
                world: None,
            })
        }
    }

    fn collect_adverbs(&mut self) -> Vec<Symbol> {
        let mut adverbs = Vec::new();
        loop {
            if self.check_adverb() {
                if let TokenType::Adverb(adv) = self.advance().kind.clone() {
                    adverbs.push(adv);
                }
                // Skip "and" between adverbs
                if self.check(&TokenType::And) {
                    self.advance();
                }
                continue;
            }
            // A trailing bare particle is a DIRECTIONAL event modifier
            // ("He sat down." → Sit(e) ∧ Down(e)). Phrasal-verb particles
            // ("gave the book up") are consumed by the phrasal lookup before
            // this point, so a particle still present here is unclaimed.
            if let TokenType::Particle(p) = self.peek().kind {
                if matches!(
                    self.tokens.get(self.current + 1).map(|t| &t.kind),
                    Some(TokenType::Period) | Some(TokenType::EOF) | None
                ) {
                    self.advance();
                    let raw = self.interner.resolve(p).to_string();
                    let mut capitalized = raw;
                    if let Some(first) = capitalized.get_mut(0..1) {
                        first.make_ascii_uppercase();
                    }
                    adverbs.push(self.interner.intern(&capitalized));
                    continue;
                }
            }
            break;
        }
        adverbs
    }

    fn check_auxiliary(&self) -> bool {
        matches!(self.peek().kind, TokenType::Auxiliary(_))
    }

    /// Check if the current auxiliary is being used as a true auxiliary (followed by "not" or verb)
    /// vs being used as a main verb (like "did" in "did it").
    ///
    /// "did not bark" → auxiliary usage (emphatic past + negation)
    /// "did run" → auxiliary usage (emphatic past)
    /// "did it" → main verb usage (past of "do" + object)
    fn is_true_auxiliary_usage(&self) -> bool {
        if self.current + 1 >= self.tokens.len() {
            return false;
        }

        let next_token = &self.tokens[self.current + 1].kind;

        // If followed by "not", it's auxiliary usage
        if matches!(next_token, TokenType::Not) {
            return true;
        }

        // If followed by a verb, it's auxiliary usage
        if matches!(next_token, TokenType::Verb { .. }) {
            return true;
        }

        // If followed by pronoun (it, him, her, etc.), article, or noun, it's main verb usage
        if matches!(
            next_token,
            TokenType::Pronoun { .. }
                | TokenType::Article(_)
                | TokenType::Noun(_)
                | TokenType::ProperName(_)
        ) {
            return false;
        }

        // Default to auxiliary usage for backward compatibility
        true
    }

    /// Check if we have an Auxiliary token that should be treated as a main verb.
    /// This is true for "did" when followed by an object (e.g., "the butler did it").
    fn check_auxiliary_as_main_verb(&self) -> bool {
        if let TokenType::Auxiliary(Time::Past) = self.peek().kind {
            // Check if followed by pronoun, article, or noun (object)
            if self.current + 1 < self.tokens.len() {
                let next = &self.tokens[self.current + 1].kind;
                matches!(
                    next,
                    TokenType::Pronoun { .. }
                        | TokenType::Article(_)
                        | TokenType::Noun(_)
                        | TokenType::ProperName(_)
                        // A numeric object ("did 49 previous jumps", "did 3
                        // routines") — "did" is the main verb, not do-support.
                        | TokenType::Number(_)
                )
            } else {
                false
            }
        } else {
            false
        }
    }

    /// Parse "did" as the main verb "do" (past tense) with a transitive object.
    /// This handles constructions like "the butler did it" → Do(e) ∧ Agent(e, butler) ∧ Theme(e, it)
    fn parse_do_as_main_verb(&mut self, subject_term: Term<'a>) -> ParseResult<&'a LogicExpr<'a>> {
        // Consume the auxiliary token (we're treating it as past tense "do")
        let aux_token = self.advance();
        let verb_time = if let TokenType::Auxiliary(time) = aux_token.kind {
            time
        } else {
            Time::Past
        };

        // Intern "Do" as the verb lemma
        let verb = self.interner.intern("Do");

        let mut object_cardinal: Option<(u32, crate::intern::Symbol, &'a LogicExpr<'a>)> = None;

        // Parse the object - handle pronouns specially
        let object_term = if let TokenType::Pronoun { .. } = self.peek().kind {
            // Pronoun object (like "it" in "did it")
            self.advance();
            // For "it", we use a generic placeholder or resolved referent
            // In the context of "did it", "it" often refers to "the crime" or "the act"
            let it_sym = self.interner.intern("it");
            Term::Constant(it_sym)
        } else if let Some(n) = self.counting_np_lookahead() {
            // "did 49 previous jumps" — a counting-NP object: bind ∃=n over the
            // deverbal noun + adjectives, wrapping the event below.
            self.advance(); // the number
            let obj_var = self.next_var_name();
            self.nominal_np_context = true;
            let obj_np_result = self.parse_noun_phrase(false);
            self.nominal_np_context = false;
            let obj_np = obj_np_result?;
            let mut restr: &'a LogicExpr<'a> = self.ctx.exprs.alloc(LogicExpr::Predicate {
                name: obj_np.noun,
                args: self.ctx.terms.alloc_slice([Term::Variable(obj_var)]),
                world: None,
            });
            for &adj in obj_np.adjectives {
                let adj_pred = self.adjective_restriction(adj, obj_var, obj_np.noun);
                restr = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                    left: restr,
                    op: TokenType::And,
                    right: adj_pred,
                });
            }
            for pp in obj_np.pps {
                let pp_sub = self.substitute_pp_placeholder(pp, obj_var);
                restr = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                    left: restr,
                    op: TokenType::And,
                    right: pp_sub,
                });
            }
            object_cardinal = Some((n, obj_var, restr));
            Term::Variable(obj_var)
        } else if self.check_number() {
            // A bare numeric object with no adjective ("did 49 jumps", "did 3
            // routines") is a measure-style Theme, like "made 49 jumps".
            *self.parse_measure_phrase()?
        } else {
            let object = self.parse_noun_phrase(false)?;
            self.noun_phrase_to_term(&object)
        };

        // Build Neo-Davidsonian event structure
        let event_var = self.get_event_var();
        let suppress_existential = self.drs.in_conditional_antecedent();

        let mut modifiers = Vec::new();
        if verb_time == Time::Past {
            modifiers.push(self.interner.intern("Past"));
        } else if verb_time == Time::Future {
            modifiers.push(self.interner.intern("Future"));
        }

        let neo_event = self.ctx.exprs.alloc(LogicExpr::NeoEvent(Box::new(NeoEventData {
            event_var,
            verb,
            roles: self.ctx.roles.alloc_slice(vec![
                (ThematicRole::Agent, subject_term),
                (ThematicRole::Theme, object_term),
            ]),
            modifiers: self.ctx.syms.alloc_slice(modifiers),
            suppress_existential,
            world: None,
        })));

        // A counting-NP object binds the event as ∃=n ("did 49 previous jumps"
        // → ∃=49 j(Jump(j) ∧ Previous(j) ∧ Do-event(…, j))).
        if let Some((n, obj_var, restr)) = object_cardinal {
            let body = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                left: restr,
                op: TokenType::And,
                right: neo_event,
            });
            return Ok(self.ctx.exprs.alloc(LogicExpr::Quantifier {
                kind: QuantifierKind::Cardinal(n),
                variable: obj_var,
                body,
                island_id: self.current_island,
            }));
        }

        Ok(neo_event)
    }

    fn check_to(&self) -> bool {
        matches!(self.peek().kind, TokenType::To)
    }

    /// The marker "to" regardless of how the lexer classified it. Context
    /// decides between `TokenType::To` and `Preposition("to")`, but the
    /// grammar concept — an infinitival or dative marker — is one thing.
    pub(super) fn check_to_marker(&self) -> bool {
        self.check_to() || self.check_preposition_is("to")
    }

    /// Look ahead in the token stream for modal subordinating verbs (would, could, should, might).
    /// These verbs allow modal subordination: continuing a hypothetical context from a prior sentence.
    /// E.g., "A wolf might enter. It would eat you." - "would" subordinates to "might".
    fn has_modal_subordination_ahead(&self) -> bool {
        // Modal subordination verbs: would, could, should, might
        // These allow access to hypothetical entities from prior modal sentences
        for i in self.current..self.tokens.len() {
            match &self.tokens[i].kind {
                TokenType::Would | TokenType::Could | TokenType::Should | TokenType::Might => {
                    return true;
                }
                // Stop looking at sentence boundary
                TokenType::Period | TokenType::EOF => break,
                _ => {}
            }
        }
        false
    }

    fn consume_verb(&mut self) -> Symbol {
        let t = self.advance().clone();
        match t.kind {
            TokenType::Verb { lemma, .. } => lemma,
            TokenType::Ambiguous { primary, .. } => match *primary {
                TokenType::Verb { lemma, .. } => lemma,
                _ => panic!("Expected verb in Ambiguous primary, got {:?}", primary),
            },
            _ => panic!("Expected verb, got {:?}", t.kind),
        }
    }

    fn consume_verb_with_metadata(&mut self) -> (Symbol, Time, Aspect, VerbClass) {
        let t = self.advance().clone();
        match t.kind {
            TokenType::Verb { lemma, time, aspect, class } => (lemma, time, aspect, class),
            TokenType::Ambiguous { primary, .. } => match *primary {
                TokenType::Verb { lemma, time, aspect, class } => (lemma, time, aspect, class),
                _ => panic!("Expected verb in Ambiguous primary, got {:?}", primary),
            },
            _ => panic!("Expected verb, got {:?}", t.kind),
        }
    }

    fn match_token(&mut self, types: &[TokenType]) -> bool {
        for t in types {
            if self.check(t) {
                self.advance();
                return true;
            }
        }
        false
    }

    fn check_quantifier(&self) -> bool {
        matches!(
            self.peek().kind,
            TokenType::All
                | TokenType::No
                | TokenType::Some
                | TokenType::Any
                | TokenType::Most
                | TokenType::Few
                | TokenType::Many
                | TokenType::Cardinal(_)
                | TokenType::AtLeast(_)
                | TokenType::AtMost(_)
        )
    }

    fn check_npi_quantifier(&self) -> bool {
        matches!(
            self.peek().kind,
            TokenType::Nobody | TokenType::Nothing | TokenType::NoOne
        )
    }

    fn check_npi_object(&self) -> bool {
        matches!(
            self.peek().kind,
            TokenType::Anything | TokenType::Anyone
        )
    }

    fn check_temporal_npi(&self) -> bool {
        matches!(
            self.peek().kind,
            TokenType::Ever | TokenType::Never
        )
    }

    fn parse_npi_quantified(&mut self) -> ParseResult<&'a LogicExpr<'a>> {
        let npi_token = self.advance().kind.clone();
        let var_name = self.next_var_name();

        let (restriction_name, is_person) = match npi_token {
            TokenType::Nobody | TokenType::NoOne => ("Person", true),
            TokenType::Nothing => ("Thing", false),
            _ => ("Thing", false),
        };

        let restriction_sym = self.interner.intern(restriction_name);
        let subject_pred = self.ctx.exprs.alloc(LogicExpr::Predicate {
            name: restriction_sym,
            args: self.ctx.terms.alloc_slice([Term::Variable(var_name)]),
            world: None,
        });

        self.negative_depth += 1;

        let verb = self.consume_verb();

        if self.check_npi_object() {
            let obj_npi_token = self.advance().kind.clone();
            let obj_var = self.next_var_name();

            let obj_restriction_name = match obj_npi_token {
                TokenType::Anything => "Thing",
                TokenType::Anyone => "Person",
                _ => "Thing",
            };

            let obj_restriction_sym = self.interner.intern(obj_restriction_name);
            let obj_restriction = self.ctx.exprs.alloc(LogicExpr::Predicate {
                name: obj_restriction_sym,
                args: self.ctx.terms.alloc_slice([Term::Variable(obj_var)]),
                world: None,
            });

            let verb_pred = self.ctx.exprs.alloc(LogicExpr::Predicate {
                name: verb,
                args: self.ctx.terms.alloc_slice([Term::Variable(var_name), Term::Variable(obj_var)]),
                world: None,
            });

            let verb_and_obj = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                left: obj_restriction,
                op: TokenType::And,
                right: verb_pred,
            });

            let inner_existential = self.ctx.exprs.alloc(LogicExpr::Quantifier {
                kind: crate::ast::QuantifierKind::Existential,
                variable: obj_var,
                body: verb_and_obj,
                island_id: self.current_island,
            });

            self.negative_depth -= 1;

            let negated = self.ctx.exprs.alloc(LogicExpr::UnaryOp {
                op: TokenType::Not,
                operand: inner_existential,
            });

            let body = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
                left: subject_pred,
                op: TokenType::Implies,
                right: negated,
            });

            return Ok(self.ctx.exprs.alloc(LogicExpr::Quantifier {
                kind: crate::ast::QuantifierKind::Universal,
                variable: var_name,
                body,
                island_id: self.current_island,
            }));
        }

        let verb_pred = self.ctx.exprs.alloc(LogicExpr::Predicate {
            name: verb,
            args: self.ctx.terms.alloc_slice([Term::Variable(var_name)]),
            world: None,
        });

        self.negative_depth -= 1;

        let negated_verb = self.ctx.exprs.alloc(LogicExpr::UnaryOp {
            op: TokenType::Not,
            operand: verb_pred,
        });

        let body = self.ctx.exprs.alloc(LogicExpr::BinaryOp {
            left: subject_pred,
            op: TokenType::Implies,
            right: negated_verb,
        });

        Ok(self.ctx.exprs.alloc(LogicExpr::Quantifier {
            kind: crate::ast::QuantifierKind::Universal,
            variable: var_name,
            body,
            island_id: self.current_island,
        }))
    }

    fn parse_temporal_npi(&mut self) -> ParseResult<&'a LogicExpr<'a>> {
        let npi_token = self.advance().kind.clone();
        let is_never = matches!(npi_token, TokenType::Never);

        let subject = self.parse_noun_phrase(true)?;

        if is_never {
            self.negative_depth += 1;
        }

        let verb = self.consume_verb();
        let verb_pred = self.ctx.exprs.alloc(LogicExpr::Predicate {
            name: verb,
            args: self.ctx.terms.alloc_slice([Term::Constant(subject.noun)]),
            world: None,
        });

        if is_never {
            self.negative_depth -= 1;
            Ok(self.ctx.exprs.alloc(LogicExpr::UnaryOp {
                op: TokenType::Not,
                operand: verb_pred,
            }))
        } else {
            Ok(verb_pred)
        }
    }

    fn check(&self, kind: &TokenType) -> bool {
        if self.is_at_end() {
            return false;
        }
        std::mem::discriminant(&self.peek().kind) == std::mem::discriminant(kind)
    }

    fn check_any(&self, kinds: &[TokenType]) -> bool {
        if self.is_at_end() {
            return false;
        }
        let current = std::mem::discriminant(&self.peek().kind);
        kinds.iter().any(|k| std::mem::discriminant(k) == current)
    }

    fn check_article(&self) -> bool {
        matches!(self.peek().kind, TokenType::Article(_))
    }

    fn advance(&mut self) -> &Token {
        if !self.is_at_end() {
            self.current += 1;
        }
        self.previous()
    }

    fn is_at_end(&self) -> bool {
        self.peek().kind == TokenType::EOF
    }

    fn peek(&self) -> &Token {
        // Clamp to the EOF terminator (guaranteed by `Parser::new`): a walk
        // that overshoots reads EOF forever instead of panicking.
        self.tokens
            .get(self.current)
            .unwrap_or_else(|| self.tokens.last().expect("stream ends with EOF"))
    }

    /// Phase 35: Check if the next token (after current) is a string literal.
    /// Used to distinguish causal `because` from Trust's `because "reason"`.
    fn peek_next_is_string_literal(&self) -> bool {
        self.tokens.get(self.current + 1)
            .map(|t| matches!(t.kind, TokenType::StringLiteral(_)))
            .unwrap_or(false)
    }

    fn previous(&self) -> &Token {
        &self.tokens[self.current - 1]
    }

    fn current_span(&self) -> crate::token::Span {
        self.peek().span
    }

    fn consume(&mut self, kind: TokenType) -> ParseResult<&Token> {
        if self.check(&kind) {
            Ok(self.advance())
        } else {
            Err(ParseError {
                kind: ParseErrorKind::UnexpectedToken {
                    expected: kind,
                    found: self.peek().kind.clone(),
                },
                span: self.current_span(),
            })
        }
    }

    /// After the first word of a proper name has been consumed, absorb any
    /// subsequent capitalized content words into one multi-word proper-name
    /// symbol ("Porcher" + "Place" → "Porcher_Place", "Highland" + "Drive" →
    /// "Highland_Drive"). The trailing words frequently lex as common
    /// nouns/verbs/adjectives, so the test is surface capitalization, not token
    /// class. Stops at the first lowercase word or non-content token.
    pub(super) fn absorb_multiword_proper_name(&mut self, first: Symbol) -> Symbol {
        let mut full = self.interner.resolve(first).to_string();
        loop {
            let next = self.peek();
            let is_content = matches!(
                next.kind,
                TokenType::ProperName(_)
                    | TokenType::Noun(_)
                    | TokenType::Adjective(_)
                    | TokenType::Verb { .. }
                    | TokenType::Ambiguous { .. }
            );
            let capitalized = self
                .interner
                .resolve(next.lexeme)
                .chars()
                .next()
                .map_or(false, |c| c.is_ascii_uppercase());
            if is_content && capitalized {
                full.push('_');
                full.push_str(&self.interner.resolve(self.peek().lexeme));
                self.advance();
            } else {
                break;
            }
        }
        self.interner.intern(&full)
    }

    fn consume_content_word(&mut self) -> ParseResult<Symbol> {
        let t = self.advance().clone();
        match t.kind {
            TokenType::Noun(s) | TokenType::Adjective(s) | TokenType::NonIntersectiveAdjective(s) => Ok(s),
            // "item"/"items" are LOGOS index keywords but ordinary nouns in
            // declarative NL — read them as the noun via their (capitalized) lexeme.
            TokenType::Item | TokenType::Items if self.mode == ParserMode::Declarative => {
                let lex = self.interner.resolve(t.lexeme);
                let mut chars = lex.chars();
                let cap = match chars.next() {
                    Some(f) => f.to_uppercase().collect::<String>() + chars.as_str(),
                    None => String::new(),
                };
                Ok(self.interner.intern(&cap))
            }
            // A quoted string in NL prose names an entity ("the \"Yellownose\"").
            TokenType::StringLiteral(s) => {
                let s_str = self.interner.resolve(s);
                let gender = Self::infer_gender(s_str);
                self.drs.introduce_proper_name(s, s, gender);
                Ok(s)
            }
            // Phase 35: Allow single-letter articles (a, an) to be used as variable names
            TokenType::Article(_) => Ok(t.lexeme),
            // "May" the month (collides with the modal token) — use its lexeme.
            TokenType::May => Ok(self.interner.intern("May")),
            // Phase 35: Allow numeric literals as content words (e.g., "equal to 42")
            TokenType::Number(s) => Ok(s),
            // Calendar-unit words ("year", "day", "week") are common nouns (the
            // lexicon carries Year/Day/Week/… entries) that the lexer tokenizes as
            // CalendarUnit for the temporal grammar. In a noun position they are
            // their singular lemma, so "four different years" → Year(...), "the
            // year was 2001" → Year. The unit variant IS the lemma.
            TokenType::CalendarUnit(u) => {
                let lemma = match u {
                    crate::token::CalendarUnit::Second => "Second",
                    crate::token::CalendarUnit::Minute => "Minute",
                    crate::token::CalendarUnit::Hour => "Hour",
                    crate::token::CalendarUnit::Day => "Day",
                    crate::token::CalendarUnit::Week => "Week",
                    crate::token::CalendarUnit::Month => "Month",
                    crate::token::CalendarUnit::Year => "Year",
                };
                Ok(self.interner.intern(lemma))
            }
            TokenType::ProperName(s) => {
                // In imperative mode, proper names are variable references that must be defined
                if self.mode == ParserMode::Imperative {
                    if !self.drs.has_referent_by_variable(s) {
                        return Err(ParseError {
                            kind: ParseErrorKind::UndefinedVariable {
                                name: self.interner.resolve(s).to_string()
                            },
                            span: t.span,
                        });
                    }
                    return Ok(s);
                }

                // Declarative mode: auto-register proper names as entities
                let s_str = self.interner.resolve(s);
                let gender = Self::infer_gender(s_str);

                // Register in DRS for cross-sentence anaphora resolution
                self.drs.introduce_proper_name(s, s, gender);

                Ok(s)
            }
            TokenType::Verb { lemma, .. } => Ok(lemma),
            TokenType::Performative(s) => Ok(s),
            TokenType::Ambiguous { primary, .. } => {
                match *primary {
                    TokenType::Noun(s) | TokenType::Adjective(s) | TokenType::NonIntersectiveAdjective(s) => Ok(s),
                    TokenType::Verb { lemma, .. } => Ok(lemma),
                    TokenType::Performative(s) => Ok(s),
                    TokenType::ProperName(s) => {
                        // In imperative mode, proper names must be defined
                        if self.mode == ParserMode::Imperative {
                            if !self.drs.has_referent_by_variable(s) {
                                return Err(ParseError {
                                    kind: ParseErrorKind::UndefinedVariable {
                                        name: self.interner.resolve(s).to_string()
                                    },
                                    span: t.span,
                                });
                            }
                            return Ok(s);
                        }
                        // Register proper name in DRS for ambiguous tokens too
                        let s_str = self.interner.resolve(s);
                        let gender = Self::infer_gender(s_str);
                        self.drs.introduce_proper_name(s, s, gender);
                        Ok(s)
                    }
                    _ => Err(ParseError {
                        kind: ParseErrorKind::ExpectedContentWord { found: *primary },
                        span: self.current_span(),
                    }),
                }
            }
            other => Err(ParseError {
                kind: ParseErrorKind::ExpectedContentWord { found: other },
                span: self.current_span(),
            }),
        }
    }

    fn consume_copula(&mut self) -> ParseResult<()> {
        if self.match_token(&[TokenType::Is, TokenType::Are, TokenType::Was, TokenType::Were]) {
            Ok(())
        } else {
            Err(ParseError {
                kind: ParseErrorKind::ExpectedCopula,
                span: self.current_span(),
            })
        }
    }

    fn check_comparative(&self) -> bool {
        matches!(self.peek().kind, TokenType::Comparative(_))
    }

    fn is_contact_clause_pattern(&self) -> bool {
        // Detect "The cat [the dog chased] ran" pattern
        // Also handles nested: "The rat [the cat [the dog chased] ate] died"
        let mut pos = self.current;

        // Skip the article we're at
        if pos < self.tokens.len() && matches!(self.tokens[pos].kind, TokenType::Article(_)) {
            pos += 1;
        } else {
            return false;
        }

        // Skip adjectives
        while pos < self.tokens.len() && matches!(self.tokens[pos].kind, TokenType::Adjective(_)) {
            pos += 1;
        }

        // Must have noun/proper name (embedded subject)
        if pos < self.tokens.len() && matches!(self.tokens[pos].kind, TokenType::Noun(_) | TokenType::ProperName(_) | TokenType::Adjective(_)) {
            pos += 1;
        } else {
            return false;
        }

        // Must have verb OR another article (nested contact clause) after
        pos < self.tokens.len() && matches!(self.tokens[pos].kind, TokenType::Verb { .. } | TokenType::Article(_))
    }

    fn check_superlative(&self) -> bool {
        matches!(self.peek().kind, TokenType::Superlative(_))
    }

    fn check_scopal_adverb(&self) -> bool {
        matches!(self.peek().kind, TokenType::ScopalAdverb(_))
    }

    fn check_temporal_adverb(&self) -> bool {
        matches!(self.peek().kind, TokenType::TemporalAdverb(_))
    }

    fn check_non_intersective_adjective(&self) -> bool {
        matches!(self.peek().kind, TokenType::NonIntersectiveAdjective(_))
    }

    fn check_focus(&self) -> bool {
        matches!(self.peek().kind, TokenType::Focus(_))
    }

    fn check_measure(&self) -> bool {
        matches!(self.peek().kind, TokenType::Measure(_))
    }

    fn check_presup_trigger(&self) -> bool {
        match &self.peek().kind {
            TokenType::PresupTrigger(_) => true,
            TokenType::Verb { lemma, .. } => {
                let s = self.interner.resolve(*lemma).to_lowercase();
                crate::lexicon::lookup_presup_trigger(&s).is_some()
            }
            TokenType::Ambiguous { primary, .. } => match primary.as_ref() {
                TokenType::Verb { lemma, .. } => {
                    let s = self.interner.resolve(*lemma).to_lowercase();
                    crate::lexicon::lookup_presup_trigger(&s).is_some()
                }
                _ => false,
            },
            _ => false,
        }
    }

    fn consume_presup_trigger(&mut self) -> crate::token::PresupKind {
        let lemma = match self.advance().kind.clone() {
            TokenType::PresupTrigger(kind) => return kind,
            TokenType::Verb { lemma, .. } => lemma,
            TokenType::Ambiguous { primary, .. } => match *primary {
                TokenType::Verb { lemma, .. } => lemma,
                other => unreachable!("guarded by check_presup_trigger, got {other:?}"),
            },
            other => unreachable!("guarded by check_presup_trigger, got {other:?}"),
        };
        let s = self.interner.resolve(lemma).to_lowercase();
        crate::lexicon::lookup_presup_trigger(&s)
            .expect("Lexicon mismatch: Verb flagged as trigger but lookup failed")
    }

    fn is_followed_by_np_object(&self) -> bool {
        if self.current + 1 >= self.tokens.len() {
            return false;
        }
        let next = &self.tokens[self.current + 1].kind;
        matches!(next,
            TokenType::ProperName(_) |
            TokenType::Article(_) |
            TokenType::Noun(_) |
            TokenType::Pronoun { .. } |
            TokenType::Reflexive |
            TokenType::Who |
            TokenType::What |
            TokenType::Where |
            TokenType::When |
            TokenType::Why
        )
    }

    fn is_followed_by_gerund(&self) -> bool {
        if self.current + 1 >= self.tokens.len() {
            return false;
        }
        matches!(self.tokens[self.current + 1].kind, TokenType::Verb { .. })
    }

    // =========================================================================
    // Phase 46: Agent System Parsing
    // =========================================================================

    /// Parse spawn statement: "Spawn a Worker called 'w1'."
    fn parse_spawn_statement(&mut self) -> ParseResult<Stmt<'a>> {
        self.advance(); // consume "Spawn"

        // Expect article (a/an)
        if !self.check_article() {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "a/an".to_string() },
                span: self.current_span(),
            });
        }
        self.advance(); // consume article

        // Get agent type name (Noun or ProperName)
        let agent_type = match &self.tokens[self.current].kind {
            TokenType::Noun(sym) | TokenType::ProperName(sym) => {
                let s = *sym;
                self.advance();
                s
            }
            _ => {
                return Err(ParseError {
                    kind: ParseErrorKind::ExpectedKeyword { keyword: "agent type".to_string() },
                    span: self.current_span(),
                });
            }
        };

        // Expect "called"
        if !self.check(&TokenType::Called) {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "called".to_string() },
                span: self.current_span(),
            });
        }
        self.advance(); // consume "called"

        // Get agent name (string literal)
        let name = if let TokenType::StringLiteral(sym) = &self.tokens[self.current].kind {
            let s = *sym;
            self.advance();
            s
        } else {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "agent name".to_string() },
                span: self.current_span(),
            });
        };

        Ok(Stmt::Spawn { agent_type, name })
    }

    /// Parse send statement: "Send Ping to 'agent'."
    fn parse_send_statement(&mut self) -> ParseResult<Stmt<'a>> {
        self.advance(); // consume "Send"

        // Optional `cached`, `unchecked`, and `compressed [with <codec>]` modifiers,
        // in any order. Bare `compressed` = deflate; `with deflate|lz4|zstd` picks it.
        let mut cached = false;
        let mut unchecked = false;
        let mut compression = None;
        let mut layout = None;
        let mut shared = false;
        let mut computed = false;
        let mut indexed = false;
        let mut deduped = false;
        loop {
            if !cached && self.check_word("cached") {
                self.advance();
                cached = true;
            } else if !shared && (self.check_word("shared") || self.check_word("known")) {
                self.advance();
                shared = true;
            } else if !indexed && (self.check_word("indexed") || self.check_word("addressable")) {
                self.advance();
                indexed = true;
            } else if !deduped && (self.check_word("deduped") || self.check_word("shared_refs")) {
                self.advance();
                deduped = true;
            } else if !computed && self.check_word("computed") {
                self.advance();
                computed = true;
            } else if !unchecked && self.check_word("unchecked") {
                self.advance();
                unchecked = true;
            } else if layout.is_none()
                && (self.check_word("fast") || self.check_word("quickly"))
            {
                self.advance();
                layout = Some(SendLayout::Fast);
            } else if layout.is_none()
                && (self.check_word("compact") || self.check_word("small"))
            {
                self.advance();
                layout = Some(SendLayout::Compact);
            } else if layout.is_none() && self.check_word("packed") {
                self.advance();
                layout = Some(SendLayout::Packed);
            } else if layout.is_none()
                && (self.check_word("smallest") || self.check_word("best"))
            {
                self.advance();
                layout = Some(SendLayout::Smallest);
            } else if layout.is_none()
                && (self.check_word("redundant") || self.check_word("tough"))
            {
                self.advance();
                layout = Some(SendLayout::Redundant);
            } else if compression.is_none() && self.check_word("compressed") {
                self.advance();
                let codec = if self.check_word("with") {
                    self.advance();
                    let name = self.interner.resolve(self.peek().lexeme).to_ascii_lowercase();
                    let c = match name.as_str() {
                        "deflate" => CompressionCodec::Deflate,
                        "lz4" => CompressionCodec::Lz4,
                        "zstd" => CompressionCodec::Zstd,
                        _ => {
                            return Err(ParseError {
                                kind: ParseErrorKind::ExpectedKeyword {
                                    keyword: "a codec (deflate, lz4, or zstd)".to_string(),
                                },
                                span: self.current_span(),
                            })
                        }
                    };
                    self.advance(); // consume the codec name
                    c
                } else {
                    CompressionCodec::Deflate
                };
                compression = Some(codec);
            } else {
                break;
            }
        }

        // Parse message expression
        let message = self.parse_imperative_expr()?;

        // Expect "to"
        if !self.check_preposition_is("to") {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "to".to_string() },
                span: self.current_span(),
            });
        }
        self.advance(); // consume "to"

        // Parse destination expression
        let destination = self.parse_imperative_expr()?;

        Ok(Stmt::SendMessage {
            message,
            destination,
            compression,
            cached,
            unchecked,
            layout,
            shared,
            computed,
            indexed,
            deduped,
        })
    }

    /// Parse await statement: "Await response from 'agent' into result."
    fn parse_await_statement(&mut self) -> ParseResult<Stmt<'a>> {
        self.advance(); // consume "Await"

        // Optional `view` knob: receive a record-list LAZILY (zero-copy, decode-on-touch).
        // Optional `stream` knob: receive a batch STREAM and deframe it into a list.
        let mut view = false;
        let mut stream = false;
        if self.check_word("view") || self.check_word("viewed") {
            view = true;
            self.advance();
        }
        if self.check_word("stream") {
            stream = true;
            self.advance();
        }

        // Skip optional "response" word
        if self.check_word("response") {
            self.advance();
        }

        // Expect "from" (can be keyword or preposition)
        if !self.check(&TokenType::From) && !self.check_preposition_is("from") {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "from".to_string() },
                span: self.current_span(),
            });
        }
        self.advance(); // consume "from"

        // Parse source expression
        let source = self.parse_imperative_expr()?;

        // Expect "into"
        if !self.check_word("into") {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "into".to_string() },
                span: self.current_span(),
            });
        }
        self.advance(); // consume "into"

        // The bound variable: a binding position accepts any content word, so a
        // name that elsewhere lexes as a verb ("reply", "run") or another keyword
        // is taken as the identifier here — the same rule as every other `let`-like
        // binding (`expect_identifier`).
        let into = self.expect_identifier()?;

        Ok(Stmt::AwaitMessage { source, into, view, stream })
    }

    /// Parse a batch stream send. The transport is the one-word knob, exactly as `Send` chooses:
    ///   `Stream <values> into <pipe>` → an in-process channel send (`SendPipe`) — CROSS-TIER (runs
    ///                                   on the VM + AOT + tree-walker), the compute-speed pro.
    ///   `Stream <values> to <peer>`   → a relay batch stream (`StreamMessage`) — the NETWORK pro
    ///                                   (framed, zero-copy deframe), on the async tree-walker tier.
    fn parse_stream_statement(&mut self) -> ParseResult<Stmt<'a>> {
        self.advance(); // consume "Stream"
        let values = self.parse_imperative_expr()?;
        // `into` <pipe>: the cross-tier in-process transport (reuses the channel-send lowering).
        if self.check(&TokenType::Into) || self.check_word("into") {
            self.advance();
            let pipe = self.parse_imperative_expr()?;
            return Ok(Stmt::SendPipe { value: values, pipe });
        }
        // `to` <peer>: the relay network transport.
        if self.check(&TokenType::To) || self.check_preposition_is("to") || self.check_word("to") {
            self.advance();
            let destination = self.parse_imperative_expr()?;
            return Ok(Stmt::StreamMessage { values, destination });
        }
        Err(ParseError {
            kind: ParseErrorKind::ExpectedKeyword { keyword: "to (relay) or into (pipe)".to_string() },
            span: self.current_span(),
        })
    }

    // =========================================================================
    // Phase 49: CRDT Statement Parsing
    // =========================================================================

    /// Parse merge statement: "Merge remote into local." or "Merge remote's field into local's field."
    fn parse_merge_statement(&mut self) -> ParseResult<Stmt<'a>> {
        self.advance(); // consume "Merge"

        // Parse source expression
        let source = self.parse_imperative_expr()?;

        // Expect "into"
        if !self.check_word("into") {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "into".to_string() },
                span: self.current_span(),
            });
        }
        self.advance(); // consume "into"

        // Parse target expression
        let target = self.parse_imperative_expr()?;

        Ok(Stmt::MergeCrdt { source, target })
    }

    /// Parse increase statement: "Increase local's points by 10."
    fn parse_increase_statement(&mut self) -> ParseResult<Stmt<'a>> {
        self.advance(); // consume "Increase"

        // Parse object with field access (e.g., "local's points")
        let expr = self.parse_imperative_expr()?;

        // Must be a field access
        let (object, field) = if let Expr::FieldAccess { object, field } = expr {
            (object, field)
        } else {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "field access (e.g., 'x's count')".to_string() },
                span: self.current_span(),
            });
        };

        // Expect "by"
        if !self.check_preposition_is("by") {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "by".to_string() },
                span: self.current_span(),
            });
        }
        self.advance(); // consume "by"

        // Parse amount
        let amount = self.parse_imperative_expr()?;

        Ok(Stmt::IncreaseCrdt { object, field: *field, amount })
    }

    /// Parse decrease statement: "Decrease game's score by 5."
    fn parse_decrease_statement(&mut self) -> ParseResult<Stmt<'a>> {
        self.advance(); // consume "Decrease"

        // Parse object with field access (e.g., "game's score")
        let expr = self.parse_imperative_expr()?;

        // Must be a field access
        let (object, field) = if let Expr::FieldAccess { object, field } = expr {
            (object, field)
        } else {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "field access (e.g., 'x's count')".to_string() },
                span: self.current_span(),
            });
        };

        // Expect "by"
        if !self.check_preposition_is("by") {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "by".to_string() },
                span: self.current_span(),
            });
        }
        self.advance(); // consume "by"

        // Parse amount
        let amount = self.parse_imperative_expr()?;

        Ok(Stmt::DecreaseCrdt { object, field: *field, amount })
    }

    /// Parse append statement: "Append value to sequence."
    fn parse_append_statement(&mut self) -> ParseResult<Stmt<'a>> {
        self.advance(); // consume "Append"

        // Parse value to append
        let value = self.parse_imperative_expr()?;

        // Expect "to" (can be TokenType::To or a preposition)
        if !self.check(&TokenType::To) && !self.check_preposition_is("to") {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "to".to_string() },
                span: self.current_span(),
            });
        }
        self.advance(); // consume "to"

        // Parse sequence expression
        let sequence = self.parse_imperative_expr()?;

        Ok(Stmt::AppendToSequence { sequence, value })
    }

    /// Parse resolve statement: "Resolve page's title to value."
    fn parse_resolve_statement(&mut self) -> ParseResult<Stmt<'a>> {
        self.advance(); // consume "Resolve"

        // Parse object with field access (e.g., "page's title")
        let expr = self.parse_imperative_expr()?;

        // Must be a field access
        let (object, field) = if let Expr::FieldAccess { object, field } = expr {
            (object, field)
        } else {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "field access (e.g., 'x's title')".to_string() },
                span: self.current_span(),
            });
        };

        // Expect "to" (can be TokenType::To or a preposition)
        if !self.check(&TokenType::To) && !self.check_preposition_is("to") {
            return Err(ParseError {
                kind: ParseErrorKind::ExpectedKeyword { keyword: "to".to_string() },
                span: self.current_span(),
            });
        }
        self.advance(); // consume "to"

        // Parse value
        let value = self.parse_imperative_expr()?;

        Ok(Stmt::ResolveConflict { object, field: *field, value })
    }

}