shape-vm 0.3.2

//! Bytecode compiler - translates AST to bytecode

use shape_ast::error::{Result, ShapeError, SourceLocation};
use std::collections::{HashMap, HashSet};
use std::sync::Arc;

use crate::blob_cache_v2::BlobCache;
/// Borrow mode for reference parameters - Shared (&) or Exclusive (&mut).
/// Kept for codegen even though the lexical borrow checker has been removed.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum BorrowMode {
    Shared,
    Exclusive,
}

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub(crate) enum ExprResultMode {
    Value,
    PreserveRef,
}

#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
pub(crate) struct ExprReferenceResult {
    pub raw_mode: Option<BorrowMode>,
    pub auto_deref_mode: Option<BorrowMode>,
}

/// A borrow place key used for encoding borrow targets in codegen.
pub type BorrowPlace = u32;
use crate::bytecode::{
    BuiltinFunction, BytecodeProgram, Constant, FunctionBlob, FunctionHash, Instruction, OpCode,
    Operand, Program as ContentAddressedProgram,
};
use crate::type_tracking::{TypeTracker, VariableTypeInfo};
use shape_ast::ast::{FunctionDef, Program, Span, TypeAnnotation};
use shape_runtime::type_schema::SchemaId;
use shape_runtime::type_system::{
    Type, TypeAnalysisMode, TypeError, TypeErrorWithLocation, analyze_program_with_mode,
    checking::MethodTable,
};

// Sub-modules
pub(crate) mod comptime;
pub(crate) mod comptime_builtins;
pub(crate) mod comptime_concrete;
pub(crate) mod comptime_target;
mod control_flow;
mod expressions;
mod functions;
mod functions_annotations;
mod functions_foreign;
mod helpers;
mod helpers_binding;
mod helpers_reference;
mod literals;
mod loops;
pub(crate) mod mir_schema_threading;
pub(crate) mod monomorphization;
mod patterns;
pub(crate) mod post_inference_verify;
mod statements;
pub mod string_interpolation;
mod trait_object_emission;

/// Loop compilation context
pub(crate) struct LoopContext {
    /// Break jump targets
    pub(crate) break_jumps: Vec<usize>,
    /// Continue jump target (usize::MAX = deferred, use continue_jumps)
    pub(crate) continue_target: usize,
    /// Optional local to store break values for expression loops
    pub(crate) break_value_local: Option<u16>,
    /// Whether a for-in iterator is on the stack (break must pop it)
    pub(crate) iterator_on_stack: bool,
    /// Drop scope depth when the loop was entered (for break/continue early exit drops)
    pub(crate) drop_scope_depth: usize,
    /// Forward-patched continue jumps for range counter loops where the
    /// increment block is after the body (so continue must forward-jump).
    pub(crate) continue_jumps: Vec<usize>,
}

/// Information about an imported symbol (fields used for diagnostics/LSP)
#[derive(Debug, Clone)]
#[allow(dead_code)]
pub(crate) struct ImportedSymbol {
    /// Original name in the source module
    pub original_name: String,
    /// Module path the symbol was imported from
    pub module_path: String,
    /// High-level kind of the imported symbol (function, type, etc.)
    /// `None` for legacy inlining path where kind is not tracked.
    pub kind: Option<shape_ast::module_utils::ModuleExportKind>,
}

/// Imported annotation binding routed through a hidden synthetic module.
#[derive(Debug, Clone)]
pub(crate) struct ImportedAnnotationSymbol {
    /// Original annotation name in the source module.
    pub original_name: String,
    /// Source module path the annotation was imported from.
    pub _module_path: String,
    /// Hidden synthetic module name that owns the compiled annotation scope.
    pub hidden_module_name: String,
}

/// Module-scoped builtin function declaration with a runtime source module.
#[derive(Debug, Clone)]
pub(crate) struct ModuleBuiltinFunction {
    /// The callable name as exported by the runtime/native module.
    pub export_name: String,
    /// Original source module path that provides the runtime implementation.
    pub source_module_path: String,
}

/// Compiler-internal scope taxonomy for name resolution.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
#[allow(dead_code)]
pub(crate) enum ResolutionScope {
    Local,
    ModuleBinding,
    NamedImport,
    NamespaceImport,
    TypeAssociated,
    Prelude,
    SyntaxReserved,
    InternalIntrinsic,
}

impl ResolutionScope {
    pub(crate) const fn label(self) -> &'static str {
        match self {
            Self::Local => "local scope",
            Self::ModuleBinding => "module scope",
            Self::NamedImport => "named import scope",
            Self::NamespaceImport => "namespace import scope",
            Self::TypeAssociated => "type-associated scope",
            Self::Prelude => "implicit prelude scope",
            Self::SyntaxReserved => "syntax-reserved scope",
            Self::InternalIntrinsic => "internal intrinsic scope",
        }
    }
}

/// Builtin lookup result annotated with the scope class it currently belongs to.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub(crate) enum BuiltinNameResolution {
    Surface {
        builtin: BuiltinFunction,
        scope: ResolutionScope,
    },
    InternalOnly {
        builtin: BuiltinFunction,
        scope: ResolutionScope,
    },
}

impl BuiltinNameResolution {
    pub(crate) const fn scope(self) -> ResolutionScope {
        match self {
            Self::Surface { scope, .. } | Self::InternalOnly { scope, .. } => scope,
        }
    }
}

#[derive(Debug, Clone)]
pub(crate) struct StructGenericInfo {
    pub type_params: Vec<shape_ast::ast::TypeParam>,
    pub runtime_field_types: HashMap<String, shape_ast::ast::TypeAnnotation>,
}

/// Whether a type's Drop impl is sync-only, async-only, or both.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub(crate) enum DropKind {
    SyncOnly,
    AsyncOnly,
    Both,
}

/// Canonical compile-time parameter passing contract.
///
/// This is the single source of truth used by compiler lowering and LSP rendering.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
pub enum ParamPassMode {
    ByValue,
    ByRefShared,
    ByRefExclusive,
}

impl ParamPassMode {
    pub const fn is_reference(self) -> bool {
        !matches!(self, Self::ByValue)
    }

    pub const fn is_exclusive(self) -> bool {
        matches!(self, Self::ByRefExclusive)
    }
}

#[derive(Debug, Clone, PartialEq, Eq)]
pub(crate) struct FunctionReturnReferenceSummary {
    pub param_index: usize,
    pub mode: BorrowMode,
    pub projection: Option<Vec<crate::mir::types::ProjectionStep>>,
}

impl From<crate::mir::analysis::ReturnReferenceSummary> for FunctionReturnReferenceSummary {
    fn from(value: crate::mir::analysis::ReturnReferenceSummary) -> Self {
        Self {
            param_index: value.param_index,
            mode: match value.kind {
                crate::mir::types::BorrowKind::Shared => BorrowMode::Shared,
                crate::mir::types::BorrowKind::Exclusive => BorrowMode::Exclusive,
            },
            projection: value.projection,
        }
    }
}

/// Per-function blob builder for content-addressed compilation.
///
/// Uses a **snapshot** strategy: records the global instruction/constant/string
/// pool sizes at the start of function compilation, then at finalization
/// extracts the delta and remaps global indices to blob-local indices.
pub(crate) struct FunctionBlobBuilder {
    /// Function name.
    pub name: String,
    /// Global instruction index where this function's code starts.
    pub instr_start: usize,
    /// Global constant pool size when this function started compiling.
    #[allow(dead_code)]
    pub const_start: usize,
    /// Global string pool size when this function started compiling.
    #[allow(dead_code)]
    pub string_start: usize,
    /// Names of functions called by this function (for dependency tracking).
    pub called_functions: Vec<String>,
    /// Type schema names this function constructs.
    pub type_schemas: Vec<String>,
    /// Accumulated permissions required by this function's direct calls.
    pub required_permissions: shape_abi_v1::PermissionSet,
}

impl FunctionBlobBuilder {
    pub fn new(name: String, instr_start: usize, const_start: usize, string_start: usize) -> Self {
        Self {
            name,
            instr_start,
            const_start,
            string_start,
            called_functions: Vec::new(),
            type_schemas: Vec::new(),
            required_permissions: shape_abi_v1::PermissionSet::pure(),
        }
    }

    /// Record that this function calls another function by name.
    pub fn record_call(&mut self, callee_name: &str) {
        if !self.called_functions.iter().any(|n| n == callee_name) {
            self.called_functions.push(callee_name.to_owned());
        }
    }

    /// Record that this function requires the given permissions
    /// (e.g., from a stdlib module call identified by capability_tags).
    pub fn record_permissions(&mut self, perms: &shape_abi_v1::PermissionSet) {
        self.required_permissions = self.required_permissions.union(perms);
    }

    /// Finalize this builder into a FunctionBlob by extracting the delta from
    /// the global program pools and remapping indices to blob-local ones.
    pub fn finalize(
        &self,
        program: &crate::bytecode::BytecodeProgram,
        func: &crate::bytecode::Function,
        blob_name_to_hash: &HashMap<String, FunctionHash>,
        instr_end: usize,
    ) -> FunctionBlob {
        use crate::bytecode::Operand;

        // Extract global-indexed instructions for this function.
        let global_instructions = &program.instructions[self.instr_start..instr_end];

        // Build constant remap: global index -> local index.
        let mut const_remap: HashMap<u16, u16> = HashMap::new();
        let mut local_constants: Vec<Constant> = Vec::new();
        // Build string remap similarly.
        let mut string_remap: HashMap<u16, u16> = HashMap::new();
        let mut local_strings: Vec<String> = Vec::new();
        // Build function operand remap: global function index -> dependency-local index.
        let mut func_remap: HashMap<u16, u16> = HashMap::new();
        // Start from explicitly recorded call dependencies, then augment with
        // function-value references found in constants/operands.
        let mut called_functions = self.called_functions.clone();

        let mut ensure_called = |callee_name: &str| -> u16 {
            if let Some(dep_idx) = called_functions.iter().position(|n| n == callee_name) {
                dep_idx as u16
            } else {
                called_functions.push(callee_name.to_owned());
                (called_functions.len() - 1) as u16
            }
        };

        // Scan instructions for all constant/string references and build
        // blob-local pools with remapped indices.
        for instr in global_instructions {
            if let Some(ref operand) = instr.operand {
                match operand {
                    Operand::Const(idx) => {
                        if !const_remap.contains_key(idx) {
                            let local_idx = local_constants.len() as u16;
                            const_remap.insert(*idx, local_idx);
                            let mut constant = program.constants[*idx as usize].clone();
                            if let Constant::Function(fid) = constant {
                                let global_idx = fid as usize;
                                if let Some(callee) = program.functions.get(global_idx) {
                                    let dep_idx = ensure_called(&callee.name);
                                    constant = Constant::Function(dep_idx);
                                }
                            }
                            local_constants.push(constant);
                        }
                    }
                    Operand::Property(idx) => {
                        if !string_remap.contains_key(idx) {
                            let local_idx = local_strings.len() as u16;
                            string_remap.insert(*idx, local_idx);
                            local_strings.push(program.strings[*idx as usize].clone());
                        }
                    }
                    Operand::Name(sid) => {
                        let gidx = sid.0 as u16;
                        if !string_remap.contains_key(&gidx) {
                            let local_idx = local_strings.len() as u16;
                            string_remap.insert(gidx, local_idx);
                            local_strings.push(program.strings[gidx as usize].clone());
                        }
                    }
                    Operand::TypedMethodCall { string_id, .. } => {
                        let gidx = *string_id;
                        if !string_remap.contains_key(&gidx) {
                            let local_idx = local_strings.len() as u16;
                            string_remap.insert(gidx, local_idx);
                            local_strings.push(program.strings[gidx as usize].clone());
                        }
                    }
                    Operand::Function(fid) => {
                        let global_idx = fid.0 as usize;
                        if !func_remap.contains_key(&fid.0) {
                            // Map global function index -> dependency-local index.
                            // If this call target was not explicitly recorded (e.g. emitted via
                            // function-valued constants), add it so content-addressed linking can
                            // remap stable function IDs correctly.
                            if let Some(callee) = program.functions.get(global_idx) {
                                let dep_idx = ensure_called(&callee.name);
                                func_remap.insert(fid.0, dep_idx);
                            }
                        }
                    }
                    // Closure spec H5: `MakeClosure` now carries the function id
                    // (plus the escape flag) in a `ClosureAlloc` operand when the
                    // closure escapes. Treat it exactly like `Operand::Function`
                    // for dependency tracking — the content-addressed blob must
                    // record the closure's compiled body as a dependency.
                    Operand::ClosureAlloc { fid, .. } => {
                        let global_idx = fid.0 as usize;
                        if !func_remap.contains_key(&fid.0) {
                            if let Some(callee) = program.functions.get(global_idx) {
                                let dep_idx = ensure_called(&callee.name);
                                func_remap.insert(fid.0, dep_idx);
                            }
                        }
                    }
                    _ => {}
                }
            }
        }

        // Remap instructions to use local indices.
        let local_instructions: Vec<Instruction> = global_instructions
            .iter()
            .map(|instr| {
                let mut remapped = instr.clone();
                if let Some(operand) = &mut remapped.operand {
                    match operand {
                        Operand::Const(idx) => {
                            if let Some(&local) = const_remap.get(idx) {
                                *idx = local;
                            }
                        }
                        Operand::Property(idx) => {
                            if let Some(&local) = string_remap.get(idx) {
                                *idx = local;
                            }
                        }
                        Operand::Name(sid) => {
                            if let Some(&local) = string_remap.get(&(sid.0 as u16)) {
                                sid.0 = local as u32;
                            }
                        }
                        Operand::TypedMethodCall { string_id, .. } => {
                            if let Some(&local) = string_remap.get(string_id) {
                                *string_id = local;
                            }
                        }
                        Operand::Function(fid) => {
                            if let Some(&local) = func_remap.get(&fid.0) {
                                fid.0 = local;
                            }
                        }
                        // Closure spec H5: parallel remap for `ClosureAlloc`.
                        Operand::ClosureAlloc { fid, .. } => {
                            if let Some(&local) = func_remap.get(&fid.0) {
                                fid.0 = local;
                            }
                        }
                        _ => {}
                    }
                }
                remapped
            })
            .collect();

        // Build dependency list from called function names.
        // Use FunctionHash::ZERO as sentinel for forward references (not yet compiled).
        let dependencies: Vec<FunctionHash> = called_functions
            .iter()
            .map(|callee| {
                blob_name_to_hash
                    .get(callee)
                    .copied()
                    .unwrap_or(FunctionHash::ZERO)
            })
            .collect();

        // Build source map from global debug info.
        let source_map: Vec<(usize, u32, u32)> = program
            .debug_info
            .line_numbers
            .iter()
            .filter(|(idx, _, _)| *idx >= self.instr_start && *idx < instr_end)
            .map(|(idx, fid, line)| (idx - self.instr_start, *fid as u32, *line))
            .collect();

        // Scan instructions for CallForeign operands and collect content hashes
        // from the program's foreign_functions table.
        let mut foreign_deps: Vec<[u8; 32]> = Vec::new();
        for instr in &local_instructions {
            if instr.opcode == crate::bytecode::OpCode::CallForeign {
                if let Some(Operand::ForeignFunction(idx)) = instr.operand {
                    if let Some(entry) = program.foreign_functions.get(idx as usize) {
                        if let Some(hash) = entry.content_hash {
                            foreign_deps.push(hash);
                        }
                    }
                }
            }
        }
        foreign_deps.sort();
        foreign_deps.dedup();

        let mut blob = FunctionBlob {
            content_hash: FunctionHash::ZERO,
            name: self.name.clone(),
            arity: func.arity,
            param_names: func.param_names.clone(),
            locals_count: func.locals_count,
            is_closure: func.is_closure,
            captures_count: func.captures_count,
            is_async: func.is_async,
            ref_params: func.ref_params.clone(),
            ref_mutates: func.ref_mutates.clone(),
            mutable_captures: func.mutable_captures.clone(),
            frame_descriptor: func.frame_descriptor.clone(),
            required_permissions: self.required_permissions.clone(),
            instructions: local_instructions,
            constants: local_constants,
            strings: local_strings,
            dependencies,
            callee_names: called_functions,
            type_schemas: self.type_schemas.clone(),
            foreign_dependencies: foreign_deps,
            source_map,
        };
        blob.finalize();
        blob
    }
}

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum TypeDiagnosticMode {
    ReliableOnly,
    Strict,
    RecoverAll,
}

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum CompileDiagnosticMode {
    FailFast,
    RecoverAll,
}

/// cluster-2-cw-IB-class-b (2026-05-16, supervisor R3 binding-ratified):
/// retained closure-literal peek used to re-run body return-type
/// inference at the value-call site with caller-context arg type hints.
/// Stored per-local-slot in `BytecodeCompiler.local_callable_closure_bodies`
/// at let-binding time (`update_callable_binding_from_expr` /
/// `FunctionExpr` arm). The body is the AST `Vec<Statement>` clone — no
/// bytecode-lowering happens at lookup time; the inference walker only
/// inspects AST shape.
#[derive(Debug, Clone)]
pub struct ClosureBodyPeek {
    /// Formal parameters of the closure literal (`|inner|` →
    /// `[FunctionParameter { pattern: Identifier("inner"), .. }]`).
    pub params: Vec<shape_ast::ast::FunctionParameter>,
    /// Closure literal body statements.
    pub body: Vec<shape_ast::ast::Statement>,
    /// Explicit `-> T` return annotation, if any.
    pub return_type: Option<shape_ast::ast::TypeAnnotation>,
    /// Compiled-function index assigned to the closure body by
    /// `compile_expr_closure`. `None` until the closure literal is
    /// actually lowered (the peek is built from the AST; the function
    /// index is assigned at compile-emission time). Used by the value-
    /// call propagation path to retroactively patch
    /// `mir.local_typed_array_element_types` for the closure body's
    /// MIR-side typed-array param seed.
    pub function_index: Option<usize>,
}

/// Phase 4b Round 6 WS-1b W16.2-C residual (2026-05-21) — identifies the
/// binding slot that holds a bare empty-array accumulator awaiting a
/// downstream-`.push()`-resolved element kind.
///
/// A `let mut out = []` either lands in a function-body local slot or a
/// top-level module binding; both are keyed by their `u16` index. The push
/// site (`compile_expr_method_call`) resolves the receiver to the same key,
/// patches the placeholder allocator, and promotes the binding.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
pub(crate) enum EmptyArrayAccumulatorKey {
    /// Function-body local slot index.
    Local(u16),
    /// Top-level module-binding index.
    ModuleBinding(u16),
}

/// Phase 4b Round 6 WS-1b W16.2-C residual — a pending bare empty-array
/// accumulator. Carries the placeholder `NewArray(0)` instruction index so
/// the first `.push()` (or the end-of-compilation finalizer) can patch it.
#[derive(Debug, Clone)]
pub(crate) struct EmptyArrayAccumulator {
    /// Instruction index of the placeholder `OpCode::NewArray` emitted at the
    /// empty-array literal site. Patched in-place to `kind.new_opcode()` once
    /// the element kind is proven.
    pub alloc_instr_idx: usize,
    /// Source location of the empty-array literal — used for the clean
    /// "element type un-resolvable" diagnostic if no push ever resolves it.
    pub literal_loc: Option<SourceLocation>,
    /// The accumulator variable's source name (for diagnostics).
    pub var_name: String,
}

/// Compiler state
pub struct BytecodeCompiler {
    /// The program being built
    pub(crate) program: BytecodeProgram,

    /// Current function being compiled
    pub(crate) current_function: Option<usize>,

    /// Local variable mappings (name -> index)
    pub(crate) locals: Vec<HashMap<String, u16>>,

    /// ModuleBinding variable mappings (name -> index)
    pub(crate) module_bindings: HashMap<String, u16>,

    /// Next local variable index
    pub(crate) next_local: u16,

    /// Next module_binding variable index
    pub(crate) next_global: u16,

    /// Loop context stack for break/continue
    pub(crate) loop_stack: Vec<LoopContext>,

    /// Counter for synthetic closure function names
    pub(crate) closure_counter: u64,

    /// Closure function indices discovered during bytecode compilation of the
    /// current function. Each entry is (closure_function_name, function_index).
    /// Used to back-patch MIR ClosurePlaceholder/ClosureCapture after compilation.
    pub(crate) closure_function_ids: Vec<(String, u16)>,

    /// Registry of closure capture layouts (v2 closure specialization Phase A).
    ///
    /// Keyed on capture signature (`Vec<ConcreteType>`): two closures with
    /// identical capture signatures share a `ClosureTypeId`. Phase C will
    /// consume this to extend the monomorphization cache key.
    pub(crate) closure_registry: shape_value::v2::closure_layout::ClosureRegistry,

    /// Mapping from closure function index to its `ClosureTypeId`.
    /// Populated alongside `closure_function_ids` as each closure literal is
    /// lowered. Phase C reads this to key monomorphization on the closure type.
    pub(crate) closure_type_ids: Vec<(u16, shape_value::v2::concrete_type::ClosureTypeId)>,

    /// Track A.1C — per-closure `CaptureKind` vector, one entry per capture
    /// in declaration order. Populated alongside `closure_type_ids` so that
    /// `compiler_impl_reference_model::build_closure_function_layouts` can
    /// construct the per-function `ClosureLayout` with the correct
    /// `CaptureKind` per capture (rather than defaulting to the
    /// `ClosureRegistry::intern`'d all-`Immutable` shape). A missing entry
    /// (closure registered via the legacy path, e.g. test helpers) falls
    /// back to all-`Immutable`, matching the pre-A.1C layout.
    pub(crate) closure_capture_kinds: Vec<(u16, Vec<shape_value::v2::closure_layout::CaptureKind>)>,

    /// Registry of `Function<A, R>` signatures (v2 closure specialization
    /// Phase F). `FunctionTypeId`s assigned here are written into
    /// `TypedClosureHeader.type_id` in the JIT path and consumed by
    /// `CallFunctionIndirect` to pick a Cranelift `call_indirect` signature.
    pub(crate) function_type_registry:
        shape_value::v2::function_type_registry::FunctionTypeRegistry,

    /// Mapping from closure function index to the `FunctionTypeId` of its
    /// callable signature (params + return). Populated alongside
    /// `closure_type_ids` when a closure literal is lowered. The JIT reads
    /// this to emit the per-`ClosureTypeId` direct-call signature and the
    /// polymorphic `CallFunctionIndirect` signature.
    pub(crate) function_type_ids: Vec<(u16, shape_value::v2::concrete_type::FunctionTypeId)>,

    /// Phase F one-shot: if set, the next closure-literal emission uses
    /// `MakeClosureHeap` instead of the legacy `MakeClosure`. The flag is
    /// consumed (reset to false) as soon as `compile_expr_closure`
    /// finishes emitting the opcode. Callers that want to force the heap
    /// ABI (e.g. the return-statement compiler when the returned value is
    /// a closure literal) set this right before lowering the closure.
    pub(crate) emit_make_closure_heap_next: bool,

    /// Wave E+5-cleanup task #108 side-channel: native-kind hint for
    /// `GetProp` emit sites where the producer-flip in `op_get_prop`
    /// pushes raw native bits (I64 / Timestamp / F64 / Bool field tags
    /// against non-heap slots). Keyed by emitted-instruction index;
    /// consumed by `last_emitted_native_kind`'s `GetProp` arm so the
    /// host-boundary synthesizer re-tags raw bits per the recorded
    /// kind. `GetProp` is `Instruction::simple` (no operand) so neither
    /// operand-decode nor walk-back recovers the field tag — the
    /// compiler must record the resolved kind at the emit site
    /// (`compile_expr_property_access`).
    pub(crate) get_prop_native_kinds: HashMap<usize, crate::type_tracking::StorageHint>,

    /// When compiling a DataTable closure method (e.g. dt.filter(row => ...)),
    /// this holds the (schema_id, type_name) to tag the closure's row parameter as RowView.
    pub(crate) closure_row_schema: Option<(u32, String)>,

    /// Strict-typing-sweep (Cluster 3): bidirectional closure inference for
    /// HOF method calls. When the next compiled closure literal is the
    /// argument to `arr.map(|x| …)` / `.filter` / `.reduce` / etc., the
    /// outer `compile_expr_method_call` resolves the receiver's element
    /// type and stashes per-user-param `TypeAnnotation` hints here. The
    /// closure compile reads these hints and attaches them to params with
    /// no explicit annotation, then clears the field. The vector indexes
    /// USER params only (excludes synthesized capture-params).
    pub(crate) pending_closure_param_types: Option<Vec<Option<shape_ast::ast::TypeAnnotation>>>,

    /// Unified type metadata for the last compiled expression.
    ///
    /// This is the single source for relational/value kind propagation
    /// (Table<T>, Indexed<T>, known object schema, etc.).
    pub(crate) last_expr_type_info: Option<VariableTypeInfo>,

    /// Type tracker for optimized field access
    pub(crate) type_tracker: TypeTracker,

    /// Schema ID of the last compiled expression (if it's a TypedObject).
    /// Used for compile-time typed merge optimization.
    pub(crate) last_expr_schema: Option<SchemaId>,

    /// Numeric type of the last compiled expression (for typed opcode emission).
    /// Set by literal compilation, variable loads, and other expression compilers.
    /// Read by binary op compilation to emit typed opcodes (e.g., MulInt).
    pub(crate) last_expr_numeric_type: Option<crate::type_tracking::NumericType>,

    /// E+5.5 Unit C step 2: captured top-level program return-kind, snapshotted
    /// right after the last item compiles (before drop-scope emission and
    /// Halt overwrite `last_expr_*`). Consumed by
    /// `populate_program_storage_hints` to populate
    /// `top_level_frame.return_kind` so the host boundary reads the kind
    /// off the parallel-kind track (per ADR-006 §2.7.7 — the deleted
    /// ValueWord-tagged synthesis is gone).
    ///
    /// Per ADR-006 §2.7.5.1 (compiler-tier intermediate state policy),
    /// "kind not yet stamped" is carried as `Option<StorageHint>` —
    /// `None` is the post-bulldozer replacement for the deleted
    /// `StorageHint::Unknown` sentinel.
    pub(crate) top_level_program_return_kind: Option<crate::type_tracking::StorageHint>,

    /// Result mode for the expression currently being compiled.
    pub(crate) current_expr_result_mode: ExprResultMode,

    /// Whether the last compiled expression left a raw reference on the stack.
    ///
    /// `auto_deref_mode` is only set for propagated ref results (identifier loads,
    /// ref-returning calls) that should implicitly dereference in value contexts.
    /// Explicit `&expr` results keep `raw_mode` without enabling auto-deref.
    pub(crate) last_expr_reference_result: ExprReferenceResult,

    /// Known pass modes for local callable bindings (closures / function aliases).
    pub(crate) local_callable_pass_modes: HashMap<u16, Vec<ParamPassMode>>,

    /// Known safe return-reference summaries for local callable bindings.
    pub(crate) local_callable_return_reference_summaries:
        HashMap<u16, FunctionReturnReferenceSummary>,

    /// Known pass modes for module-binding callable values.
    pub(crate) module_binding_callable_pass_modes: HashMap<u16, Vec<ParamPassMode>>,

    /// Known safe return-reference summaries for module-binding callable values.
    pub(crate) module_binding_callable_return_reference_summaries:
        HashMap<u16, FunctionReturnReferenceSummary>,

    /// Sweep phase 3c.1: inferred return-type names for closures stored in
    /// local slots. Populated when `update_callable_binding_from_expr`
    /// observes a `FunctionExpr` initializer; consumed by `infer_expr_type`
    /// so a `FunctionCall { name: f, .. }` against `let f = |…| body` can
    /// recover the body's return type for strict-typing binop dispatch.
    pub(crate) local_callable_return_types: HashMap<u16, String>,

    /// Sweep phase 3c.1: inferred return-type names for closures stored in
    /// module-binding slots (top-level / REPL `let f = |…|` style).
    pub(crate) module_binding_callable_return_types: HashMap<u16, String>,

    /// Sweep phase 3c.x: inferred return-type names for arrays whose elements
    /// are closure literals with a homogeneous return type. Keyed by the
    /// local slot holding the array. Consumed by `infer_expr_type` for the
    /// `arr[i](args...)` callsite (which the parser models as
    /// `MethodCall { method: "__call__", receiver: IndexAccess { .. } }`).
    /// Without this lookup, `arr[0](1) + arr[1](1)` fails strict-typing as
    /// `unknown + unknown`.
    pub(crate) local_array_callable_return_types: HashMap<u16, String>,

    /// Sweep phase 3c.x: inferred return-type names for arrays of closures
    /// stored in module-binding slots (top-level `let arr = [|x| ..., ...]`).
    pub(crate) module_binding_array_callable_return_types: HashMap<u16, String>,

    /// cluster-2-cw-IB-class-b (2026-05-16, supervisor R3 binding-
    /// ratified): retained closure-literal body for local `let f = |..|
    /// ..` bindings. Populated at let-binding time by
    /// `update_callable_binding_from_expr`'s `FunctionExpr` arm;
    /// consumed at `compile_expr_function_call`'s value-call branch when
    /// re-running closure-body return-type inference with caller-context
    /// arg types.
    ///
    /// The retained body is the AST `Vec<Statement>` clone (no lowering
    /// occurs at lookup time — the inference walker only inspects AST
    /// shape, never emits bytecode for the body). Released on
    /// `clear_callable_binding` and on per-function compilation
    /// snapshot/restore alongside the existing `local_callable_*`
    /// maps (`functions.rs:1148-1151` / `:1496-1499` / `:1607-1608`).
    ///
    /// Memory cost: bounded by the number of local closure bindings in
    /// the active function frame; the body is the same AST already held
    /// by the parent `Statement::VariableDecl` initializer, just held
    /// for the lifetime of the enclosing function-compile pass to avoid
    /// re-walking the AST at every value-call site. Released when the
    /// enclosing function compile completes.
    pub(crate) local_callable_closure_bodies:
        HashMap<u16, ClosureBodyPeek>,

    /// cluster-2-cw-IB-class-b: module-binding variant of the closure
    /// body peek. Covers top-level / REPL `let f = |..|` bindings whose
    /// slots live in the module-binding space (not the local-slot
    /// space). Populated/cleared alongside the existing
    /// `module_binding_callable_return_types` map at the
    /// `update_callable_binding_from_expr` `FunctionExpr` arm.
    pub(crate) module_binding_callable_closure_bodies:
        HashMap<u16, ClosureBodyPeek>,

    /// ADR-006 §2.7.24 Q25.C trait-object emission (Wave 2.6 round-2):
    /// per-local-slot trait name for `let a: dyn Animal = ...` bindings.
    /// Consumed by `compile_expr_method_call` (`expressions/function_calls.rs`)
    /// to route method dispatch through `OpCode::DynMethodCall` instead
    /// of the standard `OpCode::CallMethod` path. Empty for non-dyn
    /// locals.
    pub(crate) dyn_locals: HashMap<u16, String>,

    /// ADR-006 §2.7.24 Q25.C trait-object emission: per-module-binding
    /// trait name for top-level `let a: dyn Animal = ...` declarations.
    /// Same role as `dyn_locals` but for the module-binding slot space.
    pub(crate) dyn_module_bindings: HashMap<u16, String>,

    /// Named functions that safely return one reference parameter unchanged.
    pub(crate) function_return_reference_summaries: HashMap<String, FunctionReturnReferenceSummary>,

    /// The return-reference summary of the function currently being compiled, if any.
    pub(crate) current_function_return_reference_summary: Option<FunctionReturnReferenceSummary>,

    /// Type inference engine for match exhaustiveness and type checking
    pub(crate) type_inference: shape_runtime::type_system::inference::TypeInferenceEngine,

    /// Track type aliases defined in the program
    /// Maps alias name -> target type (for type validation)
    pub(crate) type_aliases: HashMap<String, String>,

    /// Current source line being compiled (for debug info)
    pub(crate) current_line: u32,

    /// Current source file ID (for multi-file debug info)
    pub(crate) current_file_id: u16,

    /// Source text (for error messages)
    pub(crate) source_text: Option<String>,

    /// Source lines (split from source_text for quick access)
    pub(crate) source_lines: Vec<String>,

    /// Imported symbols: local_name -> ImportedSymbol
    pub(crate) imported_names: HashMap<String, ImportedSymbol>,
    /// Imported annotations: local_name -> ImportedAnnotationSymbol
    pub(crate) imported_annotations: HashMap<String, ImportedAnnotationSymbol>,
    /// R8 W8 Cluster A (2026-05-24): imported `pub const NAME = expr`
    /// initializers, keyed by the local binding name (alias-respecting).
    /// At identifier-load time, references to these names compile to an
    /// inlined `PushConst(<comptime-value>)` rather than a
    /// `LoadModuleBinding` — the dispatch's "use the existing
    /// comptime-evaluated-constant mechanism (the `Constant` pool); NOT a
    /// new opcode, NOT a deferred init runtime computation" binding.
    /// ADR-006 §2.7.5 stamp-at-compile-time invariant preserved: the
    /// constant's kind is stamped from the literal's shape at compile time.
    pub(crate) imported_consts: HashMap<String, shape_ast::ast::Expr>,
    /// Qualified builtin function declarations available as module-scoped callables.
    pub(crate) module_builtin_functions: HashMap<String, ModuleBuiltinFunction>,
    /// Module namespace bindings introduced by `use module.path`.
    /// Used to avoid UFCS rewrites for module calls like `duckdb.connect(...)`.
    pub(crate) module_namespace_bindings: HashSet<String>,
    /// Imported synthetic/local module path -> original source module path.
    /// Used when code inside a wrapper module needs to dispatch to native exports
    /// from the underlying source module.
    pub(crate) module_scope_sources: HashMap<String, String>,
    /// Active lexical module scope stack while compiling `mod Name { ... }`.
    pub(crate) module_scope_stack: Vec<String>,

    /// Known exports for import suggestions: function_name -> module_path
    /// Used to provide helpful error messages like "Did you mean to import from...?"
    pub(crate) known_exports: HashMap<String, String>,
    /// Function arity bounds keyed by function name: (required_params, total_params).
    /// Required params are non-default parameters. Defaults are only allowed
    /// in trailing positions.
    pub(crate) function_arity_bounds: HashMap<String, (usize, usize)>,
    /// Function const parameter indices keyed by function name.
    /// Const parameters must receive compile-time constant arguments at call sites.
    pub(crate) function_const_params: HashMap<String, Vec<usize>>,
    /// Original function definitions keyed by function name.
    /// Used for const-template specialization at call sites.
    pub(crate) function_defs: HashMap<String, FunctionDef>,
    /// Foreign function definitions keyed by function name.
    /// Used to resolve the effective (Result-wrapped) return type at call sites.
    pub(crate) foreign_function_defs: HashMap<String, shape_ast::ast::ForeignFunctionDef>,
    /// Sweep phase 3c.x: per-(enum, variant) struct-variant field
    /// annotations. The schema-level `EnumVariantInfo` only carries field
    /// counts (`payload_fields`) and uses `__payload_N` field names with
    /// `FieldType::Any`, so the named-field types of `enum E { V { x: int,
    /// y: int } }` are otherwise lost at pattern compile time. Populated
    /// by `register_enum`; consumed by `compile_typed_enum_binding` (struct
    /// arm) so `match m::E::V { x, y } => x + y` propagates int onto x and
    /// y.
    pub(crate) enum_struct_variant_fields:
        HashMap<(String, String), Vec<(String, shape_ast::ast::TypeAnnotation)>>,
    /// R8 W7: per-(enum, variant) tuple-payload positional type
    /// annotations. Symmetric to `enum_struct_variant_fields` for
    /// tuple variants. The runtime schema collapses tuple payloads
    /// into `__payload_N: Any`, so per-position types of
    /// `enum E { V(string) }` are otherwise lost at pattern-compile
    /// time. Populated by `register_enum`; consumed by
    /// `compile_typed_enum_binding` (tuple arm) so `match E::V(id) =>
    /// id + "!"` propagates `string` onto `id`.
    pub(crate) enum_tuple_variant_fields:
        HashMap<(String, String), Vec<shape_ast::ast::TypeAnnotation>>,
    /// Cached const specializations keyed by `(base_name + const-arg fingerprint)`.
    pub(crate) const_specializations: HashMap<String, usize>,
    /// Monotonic counter for unique specialization symbol names.
    pub(crate) next_const_specialization_id: u64,
    /// Const-parameter bindings for specialized function symbols.
    /// These bindings are exposed to comptime handlers as typed module_bindings.
    /// Kinded carrier per ADR-006 §2.7 / Q7 (`KindedSlot`); the prior
    /// `shape_value::ValueWord` shape was deleted by the strict-typing
    /// bulldozer and the comptime ABI in
    /// `compiler/comptime.rs:execute_comptime_with_annotation_handler`
    /// already migrated to `(String, KindedSlot)` pairs.
    pub(crate) specialization_const_bindings:
        HashMap<String, Vec<(String, shape_value::KindedSlot)>>,

    /// Struct type definitions: type_name -> (field_names in order, definition span)
    pub(crate) struct_types: HashMap<String, (Vec<String>, shape_ast::ast::Span)>,
    /// Generic metadata for struct types used to instantiate runtime type names
    /// (e.g. `MyType<number>`) at struct-literal construction sites.
    pub(crate) struct_generic_info: HashMap<String, StructGenericInfo>,
    /// Names of `type C` declarations with native layout metadata.
    pub(crate) native_layout_types: HashSet<String>,
    /// Generated conversion pair cache keys: `c_type::object_type`.
    pub(crate) generated_native_conversion_pairs: HashSet<String>,

    /// Whether the current function being compiled is async
    pub(crate) current_function_is_async: bool,

    /// Directory of the source file being compiled (for resolving relative source paths)
    pub(crate) source_dir: Option<std::path::PathBuf>,

    /// Collected compilation errors (for multi-error reporting)
    pub(crate) errors: Vec<shape_ast::error::ShapeError>,

    /// Hoisted fields from optimistic hoisting pre-pass.
    /// Maps variable name → list of property names assigned later (e.g., a.y = 2 → "a" → ["y"]).
    /// Used to include future property assignments in inline object schemas at compile time.
    pub(crate) hoisted_fields: HashMap<String, Vec<String>>,

    /// Phase 3e: inferred FieldType for hoisted fields, when the assigned
    /// RHS is a simple literal whose primitive type is statically known.
    /// Maps variable name → property name → inferred FieldType.
    ///
    /// Used by `compile_typed_object_literal` to register the schema with
    /// concrete primitive types (I64, F64, Bool, String) instead of falling
    /// back to FieldType::Any. Without this, `let mut a = { x: 10 }; a.y =
    /// 20; a.x + a.y` types `a.y` as Any in the schema, so the binary-op
    /// numeric path declines and trait dispatch fires (which has no runtime
    /// handler for `int.add`).
    pub(crate) hoisted_field_types:
        HashMap<String, HashMap<String, shape_runtime::type_schema::FieldType>>,

    /// When compiling a variable initializer, the name of the variable being assigned to.
    /// Used by compile_typed_object_literal to include hoisted fields in the schema.
    pub(crate) pending_variable_name: Option<String>,

    /// v2 Phase 3.1: when the enclosing `let arr: Array<T> = [...]` declares
    /// an explicit `Array<T>` annotation whose element type maps to a
    /// [`v2_typed_emission::TypedArrayKind`], stash the kind here so
    /// `compile_expr_array` can lower the literal to a v2 typed-array
    /// allocation. The statement-binding code path resets this to `None`
    /// before each new initializer.
    pub(crate) pending_variable_typed_array_kind:
        Option<crate::compiler::v2_typed_emission::TypedArrayKind>,

    /// R5.4B: nested-array-literal depth.
    ///
    /// Incremented while `compile_expr_array` compiles the elements of an
    /// array literal, decremented after. When `> 0`, the compiler is inside
    /// a nested array-literal context (e.g. the inner `[1.0, 2.0]` of
    /// `[[1.0, 2.0], [3.0, 4.0]]`) and MUST refuse the typed-array fast
    /// path (`NewTypedArrayF64`/etc.) regardless of annotation or
    /// inference.
    ///
    /// Why: the v2 typed-array opcodes store the allocation as a raw
    /// native pointer on the kinded VM stack with
    /// `NativeKind::Ptr(HeapKind::TypedArray)` declared on the parallel-
    /// kind track (ADR-006 §2.7.7), not as a generic heap-tagged value.
    /// Downstream consumers that expect a generic `Array` via
    /// `slot.as_heap_value()` cannot decode a typed-array native pointer
    /// back into a generic Array (the deleted `as_heap_ref()` /
    /// `as_any_array()` carrier accessors are gone), so e.g.
    /// `intrinsic_matmul_mat` fails with "row 0 must be an array of
    /// numeric values". Refusing typed emission for inner rows forces
    /// them onto the legacy `NewArray` path, which produces a generic
    /// `HeapValue::Array` that round-trips correctly through a generic
    /// outer `Array`.
    pub(crate) nested_array_literal_depth: u32,

    /// v2 Phase 3.1: per-local-slot record of which locals hold a v2
    /// typed array (allocated via `NewTypedArrayF64/I64/I32/Bool` rather
    /// than the legacy v1 `NewTypedArray`/`NewArray`). Populated by the
    /// statement-binding code path when an `Array<T>` annotation
    /// successfully picks a typed kind. Consumed by
    /// `resolve_receiver_typed_array_kind` so the typed Get/Set/Push/Len
    /// opcodes are only emitted for receivers that were ALSO allocated
    /// as v2 typed arrays — never for legacy NaN-boxed arrays.
    pub(crate) v2_typed_array_locals:
        HashMap<u16, crate::compiler::v2_typed_emission::TypedArrayKind>,
    /// v2 Phase 3.1: per-module-binding record of v2 typed arrays.
    /// Mirrors [`v2_typed_array_locals`] for top-level bindings.
    pub(crate) v2_typed_array_module_bindings:
        HashMap<u16, crate::compiler::v2_typed_emission::TypedArrayKind>,

    /// Phase 4b Round 6 WS-1 W16.2-C (2026-05-21) — list-comprehension
    /// element-kind capture.
    ///
    /// `compile_list_comprehension` emits the result accumulator's
    /// `NewTypedArray*` allocator BEFORE the comprehension body is compiled,
    /// but the element-expression's proven scalar kind is only known AFTER
    /// the body compiles. `compile_comprehension_clauses` writes the proven
    /// [`TypedArrayKind`] here at the innermost (clause-empty) base case,
    /// reading the bytecode compiler's `last_expr_numeric_type` /
    /// `last_expr_type_info` right after the element expression compiles —
    /// per ADR-006 §2.7.5 the kind is proven at the producer site, never
    /// fabricated. `compile_list_comprehension` then patches the recorded
    /// allocator instruction with the matching typed opcode. `None` means
    /// the element kind was not statically provable — a clean compile error.
    pub(crate) comprehension_element_kind:
        Option<crate::compiler::v2_typed_emission::TypedArrayKind>,

    /// Phase 4b Round 6 WS-1 W16.2-C (2026-05-21) — instruction indices of
    /// the placeholder `ArrayPush` opcodes emitted at list-comprehension
    /// element-push sites. `compile_comprehension_clauses` records each
    /// base-case push here; `compile_list_comprehension` patches them all
    /// to the resolved `TypedArrayPush*` opcode once the element kind is
    /// known — so the typed accumulator receives a typed push that the JIT
    /// and VM both dispatch unambiguously (no generic-carrier path).
    pub(crate) comprehension_push_sites: Vec<usize>,

    /// Phase 4b Round 6 WS-1b W16.2-C residual (2026-05-21) — bare
    /// empty-array accumulator deferred-kind capture.
    ///
    /// A bare `let mut out = []` (empty array literal, no `Array<T>`
    /// annotation, no elements) cannot resolve its `TypedArrayKind` at the
    /// literal site — the element type is determined only by downstream
    /// `out.push(x)` calls. `compile_expr_array` emits a placeholder
    /// `NewArray(0)` and records its instruction index here against the
    /// binding (local slot or module binding). The FIRST `arr.push(v)` on
    /// that binding resolves the element kind from the compiled argument's
    /// proven type (ADR-006 §2.7.5 producer-side stamp — read from the
    /// type-tracker at the push site, never decoded from runtime bits, never
    /// Bool-defaulted), patches the placeholder to the matching typed
    /// `NewTypedArray*` allocator, and promotes the binding into
    /// `v2_typed_array_locals` / `v2_typed_array_module_bindings` so every
    /// subsequent push is a typed `TypedArrayPush*`. A bare empty array that
    /// is never pushed to and never annotated has a genuinely un-resolvable
    /// element type — `finalize_unresolved_empty_array_accumulators`
    /// surface-and-stops with a clean structured compile error.
    pub(crate) empty_array_accumulators: HashMap<EmptyArrayAccumulatorKey, EmptyArrayAccumulator>,

    /// Phase 4b Round 6 WS-1b — instruction index of the placeholder
    /// `NewArray(0)` emitted by the most recent `compile_expr_array` call for
    /// a bare empty array literal. The enclosing `Statement::VariableDecl` /
    /// `Item::VariableDecl` reads this immediately after the initializer
    /// compiles and re-keys it into [`empty_array_accumulators`] against the
    /// resolved binding. `None` when the last array literal was non-empty,
    /// annotated, or otherwise resolved a kind directly.
    pub(crate) pending_empty_array_alloc_idx: Option<usize>,

    /// v2 Phase 3.2: when the enclosing `let m: HashMap<K, V> = HashMap()`
    /// declares an explicit `HashMap<K, V>` annotation whose key/value pair
    /// maps to a [`v2_typed_map_emission::TypedMapKind`], stash the kind here
    /// so `compile_expr_function_call` (HashMap ctor path) can lower the
    /// allocation to a v2 typed-map opcode. The statement-binding code path
    /// resets this to `None` before each new initializer.
    pub(crate) pending_variable_typed_map_kind:
        Option<crate::compiler::v2_typed_map_emission::TypedMapKind>,

    /// v2 Phase 3.2: per-local-slot record of which locals hold a v2 typed
    /// HashMap (allocated via `NewTypedMap*` rather than the legacy
    /// `BuiltinCall(HashMapCtor)`). Populated by the statement-binding code
    /// path. Consumed by HashMap method dispatch (`m.set/.get/.has/.delete`)
    /// so the typed Set/Get/Has/Delete opcodes are only emitted for receivers
    /// that were ALSO allocated as v2 typed maps — never for legacy NaN-boxed
    /// HashMapData.
    pub(crate) v2_typed_map_locals:
        HashMap<u16, crate::compiler::v2_typed_map_emission::TypedMapKind>,

    /// v2 Phase 3.2: per-module-binding record of v2 typed maps. Mirrors
    /// [`v2_typed_map_locals`] for top-level bindings.
    pub(crate) v2_typed_map_module_bindings:
        HashMap<u16, crate::compiler::v2_typed_map_emission::TypedMapKind>,

    /// ADR-006 §2.7.27 / Item 4 ruling (W17-mutation-writeback, 2026-05-12):
    /// per-local-slot record of locals known to hold a Copy-on-Write
    /// collection (HashSet / HashMap / Deque / PriorityQueue / Array of
    /// generic carrier). Populated at let-binding time when the initializer
    /// is one of `Set()` / `HashMap()` / `Deque()` / `PriorityQueue()` /
    /// `[…]`, or when the binding has an explicit type annotation that
    /// names the container kind.
    ///
    /// Consumed by `compile_expr_method_call`'s `&mut self` writeback
    /// emission gate: for an identifier-receiver method call where
    /// `(container_kind, method_name)` matches a `MUT_SELF_*` entry, the
    /// compiler emits `Dup; StoreLocal recv` after `CallMethod` so the
    /// new (possibly Arc-cloned) receiver Arc updates the binding slot.
    pub(crate) mut_self_container_locals:
        HashMap<u16, crate::compiler::mutation_writeback::ContainerKind>,

    /// ADR-006 §2.7.27 / Item 4 ruling: per-module-binding record of
    /// mutating-container module bindings. Mirrors
    /// [`mut_self_container_locals`] for top-level bindings.
    pub(crate) mut_self_container_bindings:
        HashMap<u16, crate::compiler::mutation_writeback::ContainerKind>,

    /// ADR-006 §2.7.27 / Item 4 ruling: signal raised by container-ctor
    /// builtin call emitters (`SetCtor`, `DequeCtor`,
    /// `PriorityQueueCtor`, `HashMapCtor`) so the surrounding statement-
    /// binding code path can transfer the kind onto the target local
    /// / module binding. Mirrors the existing
    /// [`pending_variable_typed_array_kind`] convention.
    pub(crate) pending_variable_container_kind:
        Option<crate::compiler::mutation_writeback::ContainerKind>,

    /// v2 Phase 3.2: per-AST-node side table mapping a HashMap-shaped
    /// expression to its key/value `ConcreteType` pair. Populated by the
    /// `let m: HashMap<K, V> = ...` annotation path AND by inference helpers
    /// (`infer_hashmap_kv_from_context`).
    pub(crate) map_key_value_types: HashMap<
        shape_ast::ast::Span,
        (shape_value::v2::ConcreteType, shape_value::v2::ConcreteType),
    >,

    /// v2 Phase 3.2: per-local-slot side table for HashMap key/value pairs.
    pub(crate) local_map_key_value_types:
        HashMap<u16, (shape_value::v2::ConcreteType, shape_value::v2::ConcreteType)>,

    /// v2 Phase 3.2: per-module-binding side table for HashMap key/value pairs.
    pub(crate) module_binding_map_key_value_types:
        HashMap<u16, (shape_value::v2::ConcreteType, shape_value::v2::ConcreteType)>,

    /// v2 Phase 3.2: per-AST-span array element type table — used by
    /// monomorphization helpers and methods that produce arrays from maps.
    pub(crate) array_element_types: HashMap<shape_ast::ast::Span, shape_value::v2::ConcreteType>,

    /// v2 Phase 3.2: per-local-slot array element type table.
    pub(crate) local_array_element_types: HashMap<u16, shape_value::v2::ConcreteType>,

    /// v2 Phase 3.2: per-module-binding array element type table.
    pub(crate) module_binding_array_element_types: HashMap<u16, shape_value::v2::ConcreteType>,
    /// Lexical names that will later need their binding value to remain a raw reference.
    /// This is only used to choose `Value` vs `PreserveRef` lowering for bindings; MIR
    /// remains the sole authority for borrow legality.
    pub(crate) future_reference_use_name_scopes: Vec<HashSet<String>>,

    /// Known trait names (populated in the first pass so meta definitions can reference traits)
    pub(crate) known_traits: std::collections::HashSet<String>,

    /// Full trait definitions keyed by trait name.
    /// Used to install default method implementations for impl blocks that omit them.
    pub(crate) trait_defs: HashMap<String, shape_ast::ast::types::TraitDef>,

    /// J-CT.2 (2026-05-23) — comptime impl blocks deferred for in-mini-VM
    /// registration. The outer compiler does NOT desugar/register/compile
    /// methods of `comptime impl Trait for Type { ... }` blocks into the
    /// runtime program; they are skipped from runtime processing and stored
    /// here so the comptime-evaluator mini-VM (`execute_comptime` in
    /// `compiler/comptime.rs`) can prepend them as `Item::Impl` items, where
    /// the in-comptime-mode compiler then desugars + compiles them normally.
    /// Method dispatch from `instance.method()` inside a `comptime { }` block
    /// then routes through the standard UFCS / `Type::method` resolution
    /// path without a new dispatch shape (audit §2.D carve-out).
    pub(crate) comptime_impl_blocks: Vec<shape_ast::ast::types::ImplBlock>,

    /// J-CT.2 (2026-05-23) — original struct definitions captured during
    /// the first pass. The outer compiler only retains field NAMES in
    /// `struct_types`; the comptime-evaluator mini-VM needs full AST
    /// (typed annotations, generic info, annotations) to compile
    /// struct-literal constructions and field accesses inside `comptime { }`
    /// blocks that interact with `comptime_impl_blocks`. Populated in the
    /// first-pass `Item::StructType` arm.
    pub(crate) comptime_context_struct_defs:
        HashMap<String, shape_ast::ast::types::StructTypeDef>,

    /// Extension registry for comptime execution
    pub(crate) extension_registry: Option<Arc<Vec<shape_runtime::module_exports::ModuleExports>>>,

    /// Comptime field values per type: type_name -> (field_name -> bake-time
    /// constant). These are type-level constants baked at compile time
    /// with zero runtime cost. Inner map releases heap-backed comptime
    /// values (strings via `Arc<String>`, etc.) when a type's entry is
    /// removed or the compiler is dropped.
    ///
    /// Kinded carrier per ADR-006 §2.7 / Q7 (`KindedSlot`); the prior
    /// `shape_value::ValueMap` shape was deleted by the strict-typing
    /// bulldozer along with `ValueWord`. Mirrors the
    /// `comptime_builtins::ComptimeDirective::SetParamValue { value:
    /// KindedSlot }` migration already landed in
    /// `compiler/comptime_builtins.rs`.
    pub(crate) comptime_fields:
        HashMap<String, HashMap<String, shape_value::KindedSlot>>,
    /// Type diagnostic mode for shared analyzer diagnostics.
    pub(crate) type_diagnostic_mode: TypeDiagnosticMode,
    /// Expression compilation diagnostic mode.
    pub(crate) compile_diagnostic_mode: CompileDiagnosticMode,
    /// Whether this compiler instance is compiling code for comptime execution.
    /// Enables comptime-only builtins and comptime-specific statement semantics.
    pub(crate) comptime_mode: bool,
    /// Functions removed by comptime annotation handlers (`remove target`).
    /// These are still present in `program.functions` (registered in the first pass)
    /// but must produce a clear compile-time error when called instead of jumping
    /// to an invalid entry point.
    pub(crate) removed_functions: HashSet<String>,
    /// Internal guard for compiler-synthesized `__comptime__` helper calls.
    /// User source must never access `__comptime__` directly.
    pub(crate) allow_internal_comptime_namespace: bool,
    /// Method table for data-driven method signature queries.
    /// Used to replace hardcoded heuristics (e.g., is_type_preserving_table_method)
    /// with MethodTable lookups (is_self_returning, takes_closure_with_receiver_param).
    pub(crate) method_table: MethodTable,
    /// Locals that are reference-typed in the current function.
    pub(crate) ref_locals: HashSet<u16>,
    /// Subset of ref_locals that hold exclusive (`&mut`) borrows.
    /// Used to enforce the three concurrency rules at task boundaries.
    pub(crate) exclusive_ref_locals: HashSet<u16>,
    /// Subset of ref_locals that were INFERRED as by-reference (not explicitly declared `&`).
    /// Inferred-ref params are owned values passed by reference for performance;
    /// closures may capture them (the value is dereferenced at capture time).
    pub(crate) inferred_ref_locals: HashSet<u16>,
    /// Locals whose binding value is itself a first-class reference (`let r = &x`).
    /// Reads auto-deref; writes still rebind the local.
    pub(crate) reference_value_locals: HashSet<u16>,
    /// Subset of reference_value_locals that hold exclusive (`&mut`) references.
    pub(crate) exclusive_reference_value_locals: HashSet<u16>,
    /// Local variable indices declared as `const` (immutable binding).
    pub(crate) const_locals: HashSet<u16>,
    /// Module binding indices declared as `const` (immutable binding).
    pub(crate) const_module_bindings: HashSet<u16>,
    /// Local variable indices declared as immutable `let` (not `let mut` or `var`).
    pub(crate) immutable_locals: HashSet<u16>,
    /// Local variable indices that are function parameters (first N locals in a function).
    /// Used to avoid trusting inferred type hints for params with no explicit annotation.
    pub(crate) param_locals: HashSet<u16>,
    /// Module binding indices declared as immutable `let`.
    pub(crate) immutable_module_bindings: HashSet<u16>,
    /// Module bindings whose value is itself a first-class reference.
    pub(crate) reference_value_module_bindings: HashSet<u16>,
    /// Subset of reference_value_module_bindings that hold exclusive (`&mut`) references.
    pub(crate) exclusive_reference_value_module_bindings: HashSet<u16>,
    /// ModuleBinding-ref writebacks collected while compiling current call args.
    pub(crate) call_arg_module_binding_ref_writebacks: Vec<Vec<(u16, u16)>>,
    /// Inferred reference parameters for untyped params: function -> per-param flag.
    pub(crate) inferred_ref_params: HashMap<String, Vec<bool>>,
    /// Inferred mutating-reference params: function -> per-param flag.
    pub(crate) inferred_ref_mutates: HashMap<String, Vec<bool>>,
    /// Effective per-parameter pass mode (explicit + inferred), by function name.
    pub(crate) inferred_param_pass_modes: HashMap<String, Vec<ParamPassMode>>,
    /// Inferred parameter type hints for unannotated params.
    /// Keyed by function name; each entry is a per-param optional type string.
    pub(crate) inferred_param_type_hints: HashMap<String, Vec<Option<String>>>,
    /// v0.3 WS-7: inference-resolved per-parameter `ConcreteType` for
    /// UNANNOTATED params. Keyed by function name; each entry is a per-param
    /// optional `ConcreteType` projected from the program-wide type-inference
    /// engine's result. Annotated params keep `None` here (their
    /// `ConcreteType` is stamped directly from the annotation in the
    /// `function_local_concrete_types` per-fn seeding pass). This is the
    /// proof source that lets the JIT take the v2 typed-array fast path for
    /// `fn get(xs, i) { xs[i] }`-style unannotated array parameters — without
    /// it the slot stays `ConcreteType::Void`, the JIT mis-classifies the v2
    /// `TypedArray` pointer as a NaN-boxed v1 array, and the inline index
    /// load reads garbage / SIGSEGVs.
    pub(crate) inferred_param_concrete_types:
        HashMap<String, Vec<Option<shape_value::v2::ConcreteType>>>,
    /// WS-9b: inference-resolved per-parameter ANONYMOUS-OBJECT field
    /// definitions for UNANNOTATED params. Keyed by function name; each
    /// entry is a per-param optional `Vec<(field_name, FieldType)>`.
    ///
    /// A *named* struct parameter (`type Box`) resolves through the schema
    /// registry — `set_local_type_info` already stamps its `schema_id` from
    /// the `"Box"` hint name. But an *anonymous* object parameter (the shape
    /// `fn aabb(...) { { min_x: ..., ... } }` produces) has no named schema:
    /// its inference hint is the structural string `"{min_x: number, ...}"`,
    /// which matches no registered schema. `compile_function_body` consumes
    /// this map to register an inline `__inline_obj_*` schema for such a
    /// parameter and stamp the slot's `schema_id`, so `param.field` resolves
    /// to the proven field type the same way a named-struct field does. The
    /// field types are projected from inference's resolved param `Type` —
    /// proven, never fabricated; an unresolved field yields `None`.
    pub(crate) inferred_param_object_fields: HashMap<
        String,
        Vec<Option<Vec<(String, shape_runtime::type_schema::FieldType)>>>,
    >,
    /// WS-9c: per-function inferred RETURN type projected to a
    /// `Vec<(field_name, FieldType)>` when that return type is an anonymous
    /// structural object (an unannotated object-literal factory such as
    /// `fn aabb(lo, hi) { {min: lo, max: hi} }`). `compile_expr_function_call`
    /// consumes this to register an inline anonymous schema for the call's
    /// result so `aabb(...).field` / `let a = aabb(...); a.field` resolves to
    /// the proven field type — the same resolution a named-struct return type
    /// already receives. Only unannotated functions appear here (annotated
    /// returns resolve through the annotation path). Field types are projected
    /// from inference's resolved return `Type` — proven, never fabricated.
    pub(crate) inferred_return_object_fields:
        HashMap<String, Vec<(String, shape_runtime::type_schema::FieldType)>>,
    /// WS-9c: function name → registered inline anonymous schema id for an
    /// unannotated function whose inferred return type is an anonymous
    /// object. Populated once, up-front, by
    /// `register_inferred_return_object_schemas`. Consulted by
    /// `compile_expr_function_call` (to stamp `last_expr_schema`) and by the
    /// read-only `infer_expr_type` property-access path (to resolve
    /// `f(...).field` directly, with no `let` binding).
    pub(crate) function_return_schema_ids: HashMap<String, u32>,
    /// Stack of scopes, each containing locals that need Drop calls at scope exit.
    /// Each entry is (local_index, is_async).
    pub(crate) drop_locals: Vec<Vec<(u16, bool)>>,
    /// Phase V1.1C: parallel scope stack tracking locals whose storage class
    /// is `UniqueHeap` and therefore (when the ownership-moves flag is on)
    /// need an ownership-aware `DropLocal` opcode emitted at scope exit to
    /// release the owned heap allocation. Orthogonal to `drop_locals` (which
    /// drives user-facing `Drop` trait calls via `DropCall`). Populated and
    /// consumed only when `ownership_moves_enabled()` is true; otherwise the
    /// scope stack is pushed/popped in lockstep with `drop_locals` but kept
    /// empty, so the compiler's emission path is byte-identical to
    /// pre-V1.1C.
    pub(crate) ownership_drop_locals: Vec<Vec<u16>>,
    /// Per-type drop kind: tracks whether each type has sync, async, or both drop impls.
    /// Populated during the first-pass registration of impl blocks.
    pub(crate) drop_type_info: HashMap<String, DropKind>,
    /// Module bindings that need Drop calls at program exit.
    /// Each entry is (binding_index, is_async).
    pub(crate) drop_module_bindings: Vec<(u16, bool)>,
    /// Mutable closure captures in the current function being compiled.
    /// Maps captured variable name -> upvalue index (for LoadClosure/StoreClosure).
    /// Only populated while compiling a closure body that has mutable captures.
    pub(crate) mutable_closure_captures: HashMap<String, u16>,

    /// Track A.1C.2: subset of `mutable_closure_captures` whose source
    /// binding classifies as `CaptureKind::Shared` (a `var` binding
    /// mutably captured through a closure). Maps captured variable name
    /// → capture index. When the identifier lookup finds a name in this
    /// map, the closure body emits `LoadSharedCapture` /
    /// `StoreSharedCapture` (A.1B) instead of the legacy `LoadClosure`
    /// / `StoreClosure`. Populated while compiling a closure body.
    pub(crate) shared_closure_captures: HashMap<String, u16>,

    /// Track A.1C.2b: subset of `mutable_closure_captures` whose source
    /// binding classifies as `CaptureKind::OwnedMutable` (a `let mut`
    /// binding captured by move into a single closure). Maps captured
    /// variable name → capture index. When the identifier lookup finds
    /// a name in this map, the closure body emits
    /// `LoadOwnedMutableCapture` / `StoreOwnedMutableCapture` (A.1B)
    /// instead of the legacy `LoadClosure` / `StoreClosure`. Populated
    /// while compiling a closure body.
    pub(crate) owned_mutable_closure_captures: HashMap<String, u16>,

    /// Wave E: parallel to `owned_mutable_closure_captures`, records
    /// the interior `FieldKind` of each OwnedMutable capture cell. The
    /// inner kind is derived from the captured binding's resolved
    /// `ConcreteType` (`concrete_type_for_expr → ConcreteType::to_field_kind`)
    /// at the point of closure construction. The closure body uses
    /// this map to dispatch to the typed Wave D.1 opcodes
    /// (`LoadOwnedMutableCapture<Kind>` / `StoreOwnedMutableCapture<Kind>`,
    /// codes 0x140-0x155) instead of the legacy untyped `0x132`/`0x133`
    /// opcodes (kind-erased pre-strict-typing — ADR-006 §2.7.7).
    /// Populated alongside `owned_mutable_closure_captures`,
    /// saved/restored across nested closure-body compilations.
    pub(crate) owned_mutable_capture_inner_kinds:
        HashMap<String, shape_value::v2::struct_layout::FieldKind>,

    /// A2-refined / task #17: parallel to `shared_closure_captures`,
    /// records the interior `FieldKind` of each Shared (`var`) capture
    /// cell. Derived from the captured binding's resolved `ConcreteType`
    /// at closure-construction time, mirroring
    /// `owned_mutable_capture_inner_kinds`. The closure body uses this
    /// map to dispatch to the typed Wave D.2 opcodes
    /// (`LoadSharedCapture<Kind>` / `StoreSharedCapture<Kind>`, codes
    /// 0x156-0x16B) instead of the legacy untyped `0x134`/`0x135`
    /// opcodes (kind-erased pre-strict-typing — ADR-006 §2.7.7).
    /// Saved/restored across nested closure-body compilations.
    pub(crate) shared_capture_inner_kinds:
        HashMap<String, shape_value::v2::struct_layout::FieldKind>,

    /// Variables in the current scope that have been boxed into SharedCells
    /// by a mutable closure capture. When a subsequent closure captures one
    /// of these variables (even immutably), it must use the SharedCell path
    /// so it shares the same mutable cell.
    pub(crate) boxed_locals: HashSet<String>,

    /// Track A.1C.2: local slots that have been promoted to
    /// `Arc<parking_lot::Mutex<u64>>` via the `AllocSharedLocal`
    /// opcode (with the matching `NativeKind` declared on the cell's
    /// parallel-kind track per ADR-006 §2.7.8). After promotion, every
    /// outer-scope read/write of the slot
    /// must go through `LoadSharedLocal` / `StoreSharedLocal` (never plain
    /// `LoadLocal` / `StoreLocal`), and scope exit must emit
    /// `DropSharedLocal` so the Arc strong count is released exactly once
    /// per owning frame.
    ///
    /// Keyed by the binding *name* (mirroring `boxed_locals`). Populated
    /// by `compile_expr_closure` when a `var` capture escapes into a
    /// closure and gets classified as `CaptureKind::Shared`.
    pub(crate) shared_locals: HashSet<String>,

    /// Track A.1C.3: local names that have been classified as
    /// `CaptureKind::OwnedMutable` by at least one closure in the
    /// current function scope. Needed because `binding_semantics_for_name`
    /// can return `None` after an inner closure's `compile_function`
    /// wipes the type-tracker local semantics, and we need the
    /// classification to be stable across sibling closures (otherwise
    /// a second closure capturing a different `let mut` local could
    /// fall back to `Immutable`, nulling the layout's OwnedMutable mask
    /// bit and triggering a layout mismatch in `op_make_closure`).
    pub(crate) owned_mutable_locals: HashSet<String>,

    /// Session 1 (Rust-move semantics for `let mut`): names of `let mut`
    /// local bindings that have been **moved by value into a closure
    /// capture** (i.e. classified as `CaptureKind::OwnedMutable` and
    /// emitted at `op_make_closure` time as `Box::into_raw(Box::new(bits))`).
    /// After the move, the outer slot holds only a stale snapshot of the
    /// initial value — every subsequent outer-scope read or write of the
    /// same binding is a compile error ("use-after-move").
    ///
    /// Stored as `name → span-of-the-capturing-closure` so the diagnostic
    /// can point the user at the exact capture site that consumed the
    /// binding. Populated in `compile_expr_closure`, consulted in
    /// `compile_expr_identifier` and `compile_expr_assign`. Saved /
    /// restored across nested `compile_function` calls, mirroring the
    /// `shared_locals` / `owned_mutable_locals` discipline.
    pub(crate) captured_let_mut_moved: HashMap<String, Span>,

    /// Track A.1C.3: module-binding slots that have been promoted to
    /// `Arc<parking_lot::Mutex<u64>>` via `AllocSharedModuleBinding`
    /// (with the matching `NativeKind` declared on the cell's
    /// parallel-kind track per ADR-006 §2.7.8).
    /// After promotion, every outer-scope read/write of the binding must
    /// go through `LoadSharedModuleBinding` / `StoreSharedModuleBinding`
    /// (never plain `LoadModuleBinding` / `StoreModuleBinding`). Keyed
    /// by the binding's **scoped name** — the same key used by
    /// `resolve_scoped_module_binding_name` and the `module_bindings`
    /// index map. Populated by `compile_expr_closure` when a
    /// module-scope `var` is captured mutably.
    pub(crate) shared_module_bindings: HashSet<String>,

    /// Track A.1C.2: per-scope stack of slot indices that need a
    /// `DropSharedLocal` opcode at scope exit, mirroring the
    /// `ownership_drop_locals` discipline. Push in lockstep with
    /// `push_drop_scope`; pop and emit in lockstep with `pop_drop_scope`.
    pub(crate) shared_drop_locals: Vec<Vec<u16>>,

    /// Active permission set for capability checking.
    ///
    /// When set, imported stdlib functions are checked against capability_tags.
    /// If a function requires a permission not in this set, a compile error is
    /// emitted and the function never enters bytecode.
    ///
    /// `None` means no checking (backwards-compatible default).
    pub(crate) permission_set: Option<shape_abi_v1::PermissionSet>,

    // -- Content-addressed blob tracking --
    /// Active blob builder (set while compiling a function body).
    pub(crate) current_blob_builder: Option<FunctionBlobBuilder>,
    /// Completed function blobs (finalized with content hash).
    pub(crate) completed_blobs: Vec<FunctionBlob>,
    /// Map from function name to content hash (populated after finalization).
    pub(crate) blob_name_to_hash: HashMap<String, FunctionHash>,
    /// The content-addressed program produced alongside BytecodeProgram.
    pub(crate) content_addressed_program: Option<ContentAddressedProgram>,
    /// Content hash per compiled function index (function_id -> blob hash).
    /// This is the stable identity bridge for the flat runtime format.
    pub(crate) function_hashes_by_id: Vec<Option<FunctionHash>>,

    /// Optional blob-level cache for incremental compilation.
    /// When set, compiled blobs are stored after finalization and looked up
    /// by content hash to avoid redundant work across compilations.
    pub(crate) blob_cache: Option<BlobCache>,

    /// Temporary function name aliases for comptime replace body.
    /// Maps alias (e.g., `__original__`) to actual function name (e.g., `__original__myFunc`).
    /// Set before compiling a replacement body and cleared after.
    pub(crate) function_aliases: HashMap<String, String>,

    /// Parameters of the function currently being compiled.
    /// Used by match exhaustiveness checking to fall back to type annotations
    /// when the type inference engine cannot resolve a parameter's type.
    pub(crate) current_function_params: Vec<shape_ast::ast::FunctionParameter>,

    /// Legacy cache of function names collected from stdlib-loaded modules.
    ///
    /// Internal builtin access is now gated by per-definition declaring-module
    /// provenance, not by membership in this set.
    pub stdlib_function_names: HashSet<String>,

    /// Per-function flag: when true, `get_builtin_function` resolves `__*` names.
    /// Toggled during compilation for definitions originating from `std::*`.
    pub(crate) allow_internal_builtins: bool,

    /// Package-scoped native library resolutions for the current host.
    pub(crate) native_resolution_context:
        Option<shape_runtime::native_resolution::NativeResolutionSet>,

    /// Active synthetic MIR context while compiling non-function code.
    pub(crate) non_function_mir_context_stack: Vec<String>,

    /// MIR lowered for compiled functions and synthetic non-function contexts.
    pub(crate) mir_functions: HashMap<String, crate::mir::types::MirFunction>,

    /// Borrow analyses produced from lowered MIR for compiled functions and
    /// synthetic non-function contexts.
    pub(crate) mir_borrow_analyses: HashMap<String, crate::mir::BorrowAnalysis>,

    /// Storage plans produced by the storage planning pass for each function.
    /// Maps function name to the plan mapping each MIR slot to a `BindingStorageClass`.
    pub(crate) mir_storage_plans: HashMap<String, crate::mir::StoragePlan>,

    /// Per-function borrow summaries for interprocedural alias checking.
    /// Describes which parameters conflict and must not alias at call sites.
    pub(crate) function_borrow_summaries: HashMap<String, crate::mir::FunctionBorrowSummary>,

    /// Per-function mapping from AST spans to MIR program points.
    /// Used to bridge the bytecode compiler (which knows AST spans) to
    /// MIR ownership decisions (which are keyed by `Point`).
    pub(crate) mir_span_to_point:
        HashMap<String, HashMap<shape_ast::ast::Span, crate::mir::types::Point>>,

    /// Field-level definite-initialization and liveness analyses for compiled functions.
    pub(crate) mir_field_analyses: HashMap<String, crate::mir::FieldAnalysis>,

    /// Graph-compiled namespace map: local namespace name -> canonical module path.
    /// Populated during graph-driven compilation to resolve qualified names.
    pub(crate) graph_namespace_map: HashMap<String, String>,

    /// Module dependency graph (set during graph-driven compilation).
    pub(crate) module_graph: Option<std::sync::Arc<crate::module_graph::ModuleGraph>>,

    /// Per-local-slot concrete type table for the function currently being compiled.
    pub(crate) current_function_local_concrete_types: HashMap<u16, shape_value::v2::ConcreteType>,

    /// v0.3 WS-6 — per-module-binding concrete type table, populated at
    /// let-binding time from the binding's explicit `TypeAnnotation`.
    ///
    /// Consumed by the monomorphization call-site resolver
    /// (`identifier_concrete_type`) so a generic free-function call whose
    /// argument is a variable with an explicit struct / enum / `Option<T>` /
    /// `Result<T, E>` / `HashMap<K, V>` annotation can bind its type
    /// parameter — `let n: Option<int> = ...; id(n)`. The array / map
    /// element side-tables (`module_binding_array_element_types`,
    /// `module_binding_map_key_value_types`) already cover the
    /// container-element cases; this table covers the remaining
    /// fully-annotated shapes.
    pub(crate) module_binding_concrete_types: HashMap<u16, shape_value::v2::ConcreteType>,

    /// Monomorphization cache for generic function specialization.
    pub(crate) monomorphization_cache: monomorphization::cache::MonomorphizationCache,

    /// BUG3 — cycle detector for generic method / free-function monomorphization.
    ///
    /// Holds the set of `mono_key`s whose specialization is currently being
    /// compiled further down the call stack. If `ensure_monomorphic_function`
    /// is (re-)entered for a key that is already in-progress, it means the
    /// specialized body is transitively trying to resolve itself before its
    /// own `compile_function` has finished — without the guard this would
    /// overflow the compiler stack or cache the wrong index. The entry is
    /// inserted BEFORE the inner `compile_function` call and removed right
    /// after, whether compilation succeeded or failed.
    ///
    /// Note: direct self-recursion in the body is already handled by the
    /// cache-insert-before-compile behaviour; this guard only fires on the
    /// pathological transitive-resolution cycle.
    pub(crate) monomorphization_in_progress: std::collections::HashSet<String>,

    /// Monotonic counter for monomorphization specialization IDs.
    pub(crate) next_monomorphization_id: u64,

    /// Phase C — running count of closure-aware specializations emitted in
    /// the current module. When this exceeds
    /// [`monomorphization::cache::DEFAULT_CLOSURE_SPECIALIZATION_BUDGET`],
    /// further closure-aware specializations bail back to the generic
    /// (non-inlined) dispatch path.
    pub(crate) closure_specialization_count: u32,
}

impl Default for BytecodeCompiler {
    fn default() -> Self {
        Self::new()
    }
}

mod compiler_impl_initialization;
mod compiler_impl_reference_model;

/// Infer effective reference parameters and mutation behavior without compiling bytecode.
///
/// Returns `(inferred_ref_params, inferred_ref_mutates)` keyed by function name.
/// - `inferred_ref_params[f][i] == true` means parameter `i` of `f` is inferred/treated as ref.
/// - `inferred_ref_mutates[f][i] == true` means that reference parameter is mutating (`&mut`).
pub fn infer_reference_model(
    program: &Program,
) -> (HashMap<String, Vec<bool>>, HashMap<String, Vec<bool>>) {
    let (inferred_ref_params, inferred_ref_mutates, _, _, _, _, _) =
        BytecodeCompiler::infer_reference_model(program);
    (inferred_ref_params, inferred_ref_mutates)
}

/// Infer effective parameter pass modes (`ByValue` / `ByRefShared` / `ByRefExclusive`)
/// keyed by function name.
pub fn infer_param_pass_modes(program: &Program) -> HashMap<String, Vec<ParamPassMode>> {
    let (inferred_ref_params, inferred_ref_mutates, _, _, _, _, _) =
        BytecodeCompiler::infer_reference_model(program);
    BytecodeCompiler::build_param_pass_mode_map(
        program,
        &inferred_ref_params,
        &inferred_ref_mutates,
    )
}

// ADR-006 §2.7.4 / §2.7.7 — Phase 2c deferral.
//
// `compiler_tests.rs` is a deep test harness that uses `eval()`-style
// helpers returning the deleted `shape_value::ValueWord`. Per playbook
// §7 REVISED #4, the correct surface for a non-migratable test site is
// `cfg(any())`-gating rather than reintroducing the §2.7.7 forbidden
// carrier. Re-enabling is Phase 2c work tracked in playbook §10's
// Wave-β B12 deferral pattern.
#[cfg(any())]
#[path = "compiler_tests.rs"]
mod compiler_deep;
pub(crate) mod v2_array_emission;
pub(crate) mod v2_map_emission;
pub(crate) mod v2_typed_emission;
pub(crate) mod v2_typed_map_emission;

// ADR-006 §2.7.27 / Item 4 ruling (W17-mutation-writeback, 2026-05-12):
// compile-time write-back emission for `&mut self` opt-in methods on
// COW container receivers (HashSet / HashMap / Array / Deque /
// PriorityQueue / TypedArray).
pub(crate) mod mutation_writeback;