oxilean_kernel/def_eq/

types.rs

//! Auto-generated module
//!
//! 🤖 Generated with [SplitRS](https://github.com/cool-japan/splitrs)

use super::functions::*;
use crate::equiv_manager::EquivManager;
use crate::expr_util::{get_app_args, get_app_fn, has_loose_bvar};
use crate::instantiate::instantiate_type_lparams;
use crate::level;
use crate::reduce::{Reducer, ReducibilityHint, TransparencyMode};
use crate::subst::instantiate;
use crate::{Environment, Expr, Level};
use std::collections::HashMap;

/// A tagged union for representing a simple two-case discriminated union.
#[allow(dead_code)]
pub enum Either2<A, B> {
    /// The first alternative.
    First(A),
    /// The second alternative.
    Second(B),
}
#[allow(dead_code)]
impl<A, B> Either2<A, B> {
    /// Returns `true` if this is the first alternative.
    pub fn is_first(&self) -> bool {
        matches!(self, Either2::First(_))
    }
    /// Returns `true` if this is the second alternative.
    pub fn is_second(&self) -> bool {
        matches!(self, Either2::Second(_))
    }
    /// Returns the first value if present.
    pub fn first(self) -> Option<A> {
        match self {
            Either2::First(a) => Some(a),
            _ => None,
        }
    }
    /// Returns the second value if present.
    pub fn second(self) -> Option<B> {
        match self {
            Either2::Second(b) => Some(b),
            _ => None,
        }
    }
    /// Maps over the first alternative.
    pub fn map_first<C, F: FnOnce(A) -> C>(self, f: F) -> Either2<C, B> {
        match self {
            Either2::First(a) => Either2::First(f(a)),
            Either2::Second(b) => Either2::Second(b),
        }
    }
}
/// A mutable reference stack for tracking the current "focus" in a tree traversal.
#[allow(dead_code)]
pub struct FocusStack<T> {
    items: Vec<T>,
}
#[allow(dead_code)]
impl<T> FocusStack<T> {
    /// Creates an empty focus stack.
    pub fn new() -> Self {
        Self { items: Vec::new() }
    }
    /// Focuses on `item`.
    pub fn focus(&mut self, item: T) {
        self.items.push(item);
    }
    /// Blurs (pops) the current focus.
    pub fn blur(&mut self) -> Option<T> {
        self.items.pop()
    }
    /// Returns the current focus, or `None`.
    pub fn current(&self) -> Option<&T> {
        self.items.last()
    }
    /// Returns the focus depth.
    pub fn depth(&self) -> usize {
        self.items.len()
    }
    /// Returns `true` if there is no current focus.
    pub fn is_empty(&self) -> bool {
        self.items.is_empty()
    }
}
/// A simple ordered index mapping names to integer IDs.
#[allow(dead_code)]
#[derive(Debug, Clone, Default)]
pub struct NameIndex {
    names: Vec<String>,
    index: std::collections::HashMap<String, usize>,
}
impl NameIndex {
    /// Create a new empty name index.
    #[allow(dead_code)]
    pub fn new() -> Self {
        Self::default()
    }
    /// Insert a name, returning its ID.
    /// If the name is already present, returns the existing ID.
    #[allow(dead_code)]
    pub fn insert(&mut self, name: impl Into<String>) -> usize {
        let name = name.into();
        if let Some(&id) = self.index.get(&name) {
            return id;
        }
        let id = self.names.len();
        self.index.insert(name.clone(), id);
        self.names.push(name);
        id
    }
    /// Get the ID for a name, if it exists.
    #[allow(dead_code)]
    pub fn get_id(&self, name: &str) -> Option<usize> {
        self.index.get(name).copied()
    }
    /// Get the name for an ID.
    #[allow(dead_code)]
    pub fn get_name(&self, id: usize) -> Option<&str> {
        self.names.get(id).map(|s| s.as_str())
    }
    /// Get the number of names in the index.
    #[allow(dead_code)]
    pub fn len(&self) -> usize {
        self.names.len()
    }
    /// Check if the index is empty.
    #[allow(dead_code)]
    pub fn is_empty(&self) -> bool {
        self.names.is_empty()
    }
    /// Get all names in insertion order.
    #[allow(dead_code)]
    pub fn all_names(&self) -> &[String] {
        &self.names
    }
}
/// A versioned record that stores a history of values.
#[allow(dead_code)]
pub struct VersionedRecord<T: Clone> {
    history: Vec<T>,
}
#[allow(dead_code)]
impl<T: Clone> VersionedRecord<T> {
    /// Creates a new record with an initial value.
    pub fn new(initial: T) -> Self {
        Self {
            history: vec![initial],
        }
    }
    /// Updates the record with a new version.
    pub fn update(&mut self, val: T) {
        self.history.push(val);
    }
    /// Returns the current (latest) value.
    pub fn current(&self) -> &T {
        self.history
            .last()
            .expect("VersionedRecord history is always non-empty after construction")
    }
    /// Returns the value at version `n` (0-indexed), or `None`.
    pub fn at_version(&self, n: usize) -> Option<&T> {
        self.history.get(n)
    }
    /// Returns the version number of the current value.
    pub fn version(&self) -> usize {
        self.history.len() - 1
    }
    /// Returns `true` if more than one version exists.
    pub fn has_history(&self) -> bool {
        self.history.len() > 1
    }
}
/// A type-erased function pointer with arity tracking.
#[allow(dead_code)]
pub struct RawFnPtr {
    /// The raw function pointer (stored as usize for type erasure).
    ptr: usize,
    arity: usize,
    name: String,
}
#[allow(dead_code)]
impl RawFnPtr {
    /// Creates a new raw function pointer descriptor.
    pub fn new(ptr: usize, arity: usize, name: impl Into<String>) -> Self {
        Self {
            ptr,
            arity,
            name: name.into(),
        }
    }
    /// Returns the arity.
    pub fn arity(&self) -> usize {
        self.arity
    }
    /// Returns the name.
    pub fn name(&self) -> &str {
        &self.name
    }
    /// Returns the raw pointer value.
    pub fn raw(&self) -> usize {
        self.ptr
    }
}
/// A batch checker that can check multiple pairs efficiently.
#[allow(dead_code)]
pub struct BatchDefEqChecker<'env> {
    checker: DefEqChecker<'env>,
}
impl<'env> BatchDefEqChecker<'env> {
    /// Create a new batch checker.
    #[allow(dead_code)]
    pub fn new(env: &'env Environment) -> Self {
        Self {
            checker: DefEqChecker::new(env),
        }
    }
    /// Check definitional equality for a single pair.
    #[allow(dead_code)]
    pub fn check(&mut self, t: &Expr, s: &Expr) -> bool {
        self.checker.is_def_eq(t, s)
    }
    /// Check all pairs in a list; returns true iff all pairs are def-equal.
    #[allow(dead_code)]
    pub fn check_all(&mut self, pairs: &[(Expr, Expr)]) -> bool {
        pairs.iter().all(|(t, s)| self.checker.is_def_eq(t, s))
    }
    /// Check any pair in a list; returns true iff at least one pair is def-equal.
    #[allow(dead_code)]
    pub fn check_any(&mut self, pairs: &[(Expr, Expr)]) -> bool {
        pairs.iter().any(|(t, s)| self.checker.is_def_eq(t, s))
    }
    /// Count how many pairs in the list are definitionally equal.
    #[allow(dead_code)]
    pub fn count_equal(&mut self, pairs: &[(Expr, Expr)]) -> usize {
        pairs
            .iter()
            .filter(|(t, s)| self.checker.is_def_eq(t, s))
            .count()
    }
    /// Reset the checker (clears caches).
    #[allow(dead_code)]
    pub fn reset(&mut self) {
        self.checker.cache.clear();
        self.checker.equiv_manager.clear();
    }
}
/// A generic counter that tracks min/max/sum for statistical summaries.
#[allow(dead_code)]
pub struct StatSummary {
    count: u64,
    sum: f64,
    min: f64,
    max: f64,
}
#[allow(dead_code)]
impl StatSummary {
    /// Creates an empty summary.
    pub fn new() -> Self {
        Self {
            count: 0,
            sum: 0.0,
            min: f64::INFINITY,
            max: f64::NEG_INFINITY,
        }
    }
    /// Records a sample.
    pub fn record(&mut self, val: f64) {
        self.count += 1;
        self.sum += val;
        if val < self.min {
            self.min = val;
        }
        if val > self.max {
            self.max = val;
        }
    }
    /// Returns the mean, or `None` if no samples.
    pub fn mean(&self) -> Option<f64> {
        if self.count == 0 {
            None
        } else {
            Some(self.sum / self.count as f64)
        }
    }
    /// Returns the minimum, or `None` if no samples.
    pub fn min(&self) -> Option<f64> {
        if self.count == 0 {
            None
        } else {
            Some(self.min)
        }
    }
    /// Returns the maximum, or `None` if no samples.
    pub fn max(&self) -> Option<f64> {
        if self.count == 0 {
            None
        } else {
            Some(self.max)
        }
    }
    /// Returns the count of recorded samples.
    pub fn count(&self) -> u64 {
        self.count
    }
}
/// A pair of `StatSummary` values tracking before/after a transformation.
#[allow(dead_code)]
pub struct TransformStat {
    before: StatSummary,
    after: StatSummary,
}
#[allow(dead_code)]
impl TransformStat {
    /// Creates a new transform stat recorder.
    pub fn new() -> Self {
        Self {
            before: StatSummary::new(),
            after: StatSummary::new(),
        }
    }
    /// Records a before value.
    pub fn record_before(&mut self, v: f64) {
        self.before.record(v);
    }
    /// Records an after value.
    pub fn record_after(&mut self, v: f64) {
        self.after.record(v);
    }
    /// Returns the mean reduction ratio (after/before).
    pub fn mean_ratio(&self) -> Option<f64> {
        let b = self.before.mean()?;
        let a = self.after.mean()?;
        if b.abs() < f64::EPSILON {
            return None;
        }
        Some(a / b)
    }
}
/// A write-once cell.
#[allow(dead_code)]
pub struct WriteOnce<T> {
    value: std::cell::Cell<Option<T>>,
}
#[allow(dead_code)]
impl<T: Copy> WriteOnce<T> {
    /// Creates an empty write-once cell.
    pub fn new() -> Self {
        Self {
            value: std::cell::Cell::new(None),
        }
    }
    /// Writes a value.  Returns `false` if already written.
    pub fn write(&self, val: T) -> bool {
        if self.value.get().is_some() {
            return false;
        }
        self.value.set(Some(val));
        true
    }
    /// Returns the value if written.
    pub fn read(&self) -> Option<T> {
        self.value.get()
    }
    /// Returns `true` if the value has been written.
    pub fn is_written(&self) -> bool {
        self.value.get().is_some()
    }
}
/// A hierarchical configuration tree.
#[allow(dead_code)]
pub struct ConfigNode {
    key: String,
    value: Option<String>,
    children: Vec<ConfigNode>,
}
#[allow(dead_code)]
impl ConfigNode {
    /// Creates a leaf config node with a value.
    pub fn leaf(key: impl Into<String>, value: impl Into<String>) -> Self {
        Self {
            key: key.into(),
            value: Some(value.into()),
            children: Vec::new(),
        }
    }
    /// Creates a section node with children.
    pub fn section(key: impl Into<String>) -> Self {
        Self {
            key: key.into(),
            value: None,
            children: Vec::new(),
        }
    }
    /// Adds a child node.
    pub fn add_child(&mut self, child: ConfigNode) {
        self.children.push(child);
    }
    /// Returns the key.
    pub fn key(&self) -> &str {
        &self.key
    }
    /// Returns the value, or `None` for section nodes.
    pub fn value(&self) -> Option<&str> {
        self.value.as_deref()
    }
    /// Returns the number of children.
    pub fn num_children(&self) -> usize {
        self.children.len()
    }
    /// Looks up a dot-separated path.
    pub fn lookup(&self, path: &str) -> Option<&str> {
        let mut parts = path.splitn(2, '.');
        let head = parts.next()?;
        let tail = parts.next();
        if head != self.key {
            return None;
        }
        match tail {
            None => self.value.as_deref(),
            Some(rest) => self.children.iter().find_map(|c| c.lookup_relative(rest)),
        }
    }
    fn lookup_relative(&self, path: &str) -> Option<&str> {
        let mut parts = path.splitn(2, '.');
        let head = parts.next()?;
        let tail = parts.next();
        if head != self.key {
            return None;
        }
        match tail {
            None => self.value.as_deref(),
            Some(rest) => self.children.iter().find_map(|c| c.lookup_relative(rest)),
        }
    }
}
/// Statistics for a DefEq check run.
#[allow(dead_code)]
#[derive(Debug, Clone, Default)]
pub struct DefEqStats {
    /// Number of cache hits.
    pub cache_hits: u64,
    /// Number of cache misses.
    pub cache_misses: u64,
    /// Number of reduction steps taken.
    pub reduction_steps: u64,
    /// Number of successful delta reductions.
    pub delta_reductions: u64,
    /// Number of beta reductions.
    pub beta_reductions: u64,
    /// Number of eta expansions tried.
    pub eta_attempts: u64,
    /// Number of equiv-manager hits.
    pub equiv_hits: u64,
}
impl DefEqStats {
    /// Compute the cache hit rate in [0, 1].
    #[allow(dead_code)]
    pub fn cache_hit_rate(&self) -> f64 {
        let total = self.cache_hits + self.cache_misses;
        if total == 0 {
            1.0
        } else {
            self.cache_hits as f64 / total as f64
        }
    }
    /// Compute total number of cache accesses.
    #[allow(dead_code)]
    pub fn total_cache_accesses(&self) -> u64 {
        self.cache_hits + self.cache_misses
    }
    /// Compute total number of reductions across all kinds.
    #[allow(dead_code)]
    pub fn total_reductions(&self) -> u64 {
        self.reduction_steps + self.delta_reductions + self.beta_reductions
    }
}
/// A reusable scratch buffer for path computations.
#[allow(dead_code)]
pub struct PathBuf {
    components: Vec<String>,
}
#[allow(dead_code)]
impl PathBuf {
    /// Creates a new empty path buffer.
    pub fn new() -> Self {
        Self {
            components: Vec::new(),
        }
    }
    /// Pushes a component.
    pub fn push(&mut self, comp: impl Into<String>) {
        self.components.push(comp.into());
    }
    /// Pops the last component.
    pub fn pop(&mut self) {
        self.components.pop();
    }
    /// Returns the current path as a `/`-separated string.
    pub fn as_str(&self) -> String {
        self.components.join("/")
    }
    /// Returns the depth of the path.
    pub fn depth(&self) -> usize {
        self.components.len()
    }
    /// Clears the path.
    pub fn clear(&mut self) {
        self.components.clear();
    }
}
/// A simple decision tree node for rule dispatching.
#[allow(dead_code)]
#[allow(missing_docs)]
pub enum DecisionNode {
    /// A leaf with an action string.
    Leaf(String),
    /// An interior node: check `key` equals `val` → `yes_branch`, else `no_branch`.
    Branch {
        key: String,
        val: String,
        yes_branch: Box<DecisionNode>,
        no_branch: Box<DecisionNode>,
    },
}
#[allow(dead_code)]
impl DecisionNode {
    /// Evaluates the decision tree with the given context.
    pub fn evaluate(&self, ctx: &std::collections::HashMap<String, String>) -> &str {
        match self {
            DecisionNode::Leaf(action) => action.as_str(),
            DecisionNode::Branch {
                key,
                val,
                yes_branch,
                no_branch,
            } => {
                let actual = ctx.get(key).map(|s| s.as_str()).unwrap_or("");
                if actual == val.as_str() {
                    yes_branch.evaluate(ctx)
                } else {
                    no_branch.evaluate(ctx)
                }
            }
        }
    }
    /// Returns the depth of the decision tree.
    pub fn depth(&self) -> usize {
        match self {
            DecisionNode::Leaf(_) => 0,
            DecisionNode::Branch {
                yes_branch,
                no_branch,
                ..
            } => 1 + yes_branch.depth().max(no_branch.depth()),
        }
    }
}
/// A sparse vector: stores only non-default elements.
#[allow(dead_code)]
pub struct SparseVec<T: Default + Clone + PartialEq> {
    entries: std::collections::HashMap<usize, T>,
    default_: T,
    logical_len: usize,
}
#[allow(dead_code)]
impl<T: Default + Clone + PartialEq> SparseVec<T> {
    /// Creates a new sparse vector with logical length `len`.
    pub fn new(len: usize) -> Self {
        Self {
            entries: std::collections::HashMap::new(),
            default_: T::default(),
            logical_len: len,
        }
    }
    /// Sets element at `idx`.
    pub fn set(&mut self, idx: usize, val: T) {
        if val == self.default_ {
            self.entries.remove(&idx);
        } else {
            self.entries.insert(idx, val);
        }
    }
    /// Gets element at `idx`.
    pub fn get(&self, idx: usize) -> &T {
        self.entries.get(&idx).unwrap_or(&self.default_)
    }
    /// Returns the logical length.
    pub fn len(&self) -> usize {
        self.logical_len
    }
    /// Returns whether the collection is empty.
    pub fn is_empty(&self) -> bool {
        self.len() == 0
    }
    /// Returns the number of non-default elements.
    pub fn nnz(&self) -> usize {
        self.entries.len()
    }
}
/// A counter that can measure elapsed time between snapshots.
#[allow(dead_code)]
pub struct Stopwatch {
    start: std::time::Instant,
    splits: Vec<f64>,
}
#[allow(dead_code)]
impl Stopwatch {
    /// Creates and starts a new stopwatch.
    pub fn start() -> Self {
        Self {
            start: std::time::Instant::now(),
            splits: Vec::new(),
        }
    }
    /// Records a split time (elapsed since start).
    pub fn split(&mut self) {
        self.splits.push(self.elapsed_ms());
    }
    /// Returns total elapsed milliseconds since start.
    pub fn elapsed_ms(&self) -> f64 {
        self.start.elapsed().as_secs_f64() * 1000.0
    }
    /// Returns all recorded split times.
    pub fn splits(&self) -> &[f64] {
        &self.splits
    }
    /// Returns the number of splits.
    pub fn num_splits(&self) -> usize {
        self.splits.len()
    }
}
/// A label set for a graph node.
#[allow(dead_code)]
pub struct LabelSet {
    labels: Vec<String>,
}
#[allow(dead_code)]
impl LabelSet {
    /// Creates a new empty label set.
    pub fn new() -> Self {
        Self { labels: Vec::new() }
    }
    /// Adds a label (deduplicates).
    pub fn add(&mut self, label: impl Into<String>) {
        let s = label.into();
        if !self.labels.contains(&s) {
            self.labels.push(s);
        }
    }
    /// Returns `true` if `label` is present.
    pub fn has(&self, label: &str) -> bool {
        self.labels.iter().any(|l| l == label)
    }
    /// Returns the count of labels.
    pub fn count(&self) -> usize {
        self.labels.len()
    }
    /// Returns all labels.
    pub fn all(&self) -> &[String] {
        &self.labels
    }
}
/// A pool of reusable string buffers.
#[allow(dead_code)]
pub struct StringPool {
    free: Vec<String>,
}
#[allow(dead_code)]
impl StringPool {
    /// Creates a new empty string pool.
    pub fn new() -> Self {
        Self { free: Vec::new() }
    }
    /// Takes a string from the pool (may be empty).
    pub fn take(&mut self) -> String {
        self.free.pop().unwrap_or_default()
    }
    /// Returns a string to the pool.
    pub fn give(&mut self, mut s: String) {
        s.clear();
        self.free.push(s);
    }
    /// Returns the number of free strings in the pool.
    pub fn free_count(&self) -> usize {
        self.free.len()
    }
}
/// Status of a lazy delta reduction step.
#[derive(Debug, PartialEq, Eq)]
pub enum ReductionStatus {
    /// Continue: reduced one or both sides.
    Continue(Expr, Expr),
    /// Definitely equal.
    Equal,
    /// Definitely not equal (both stuck).
    Stuck,
    /// Unknown: need more reduction.
    Unknown,
}
/// A simple stack-based calculator for arithmetic expressions.
#[allow(dead_code)]
pub struct StackCalc {
    stack: Vec<i64>,
}
#[allow(dead_code)]
impl StackCalc {
    /// Creates a new empty calculator.
    pub fn new() -> Self {
        Self { stack: Vec::new() }
    }
    /// Pushes an integer literal.
    pub fn push(&mut self, n: i64) {
        self.stack.push(n);
    }
    /// Adds the top two values.  Panics if fewer than two values.
    pub fn add(&mut self) {
        let b = self
            .stack
            .pop()
            .expect("stack must have at least two values for add");
        let a = self
            .stack
            .pop()
            .expect("stack must have at least two values for add");
        self.stack.push(a + b);
    }
    /// Subtracts top from second.
    pub fn sub(&mut self) {
        let b = self
            .stack
            .pop()
            .expect("stack must have at least two values for sub");
        let a = self
            .stack
            .pop()
            .expect("stack must have at least two values for sub");
        self.stack.push(a - b);
    }
    /// Multiplies the top two values.
    pub fn mul(&mut self) {
        let b = self
            .stack
            .pop()
            .expect("stack must have at least two values for mul");
        let a = self
            .stack
            .pop()
            .expect("stack must have at least two values for mul");
        self.stack.push(a * b);
    }
    /// Peeks the top value.
    pub fn peek(&self) -> Option<i64> {
        self.stack.last().copied()
    }
    /// Returns the stack depth.
    pub fn depth(&self) -> usize {
        self.stack.len()
    }
}
/// Configuration for the definitional equality checker.
#[allow(dead_code)]
#[derive(Debug, Clone)]
pub struct DefEqConfig {
    /// Maximum number of reduction steps before giving up.
    pub max_steps: u32,
    /// Whether to use proof irrelevance (Props are equal).
    pub proof_irrelevance: bool,
    /// Whether to check eta-expansion.
    pub eta: bool,
    /// Whether to try lazy delta reduction.
    pub lazy_delta: bool,
    /// Transparency mode for unfolding.
    pub transparency: TransparencyMode,
}
impl DefEqConfig {
    /// Create a config for checking definitional equality with full unfolding.
    #[allow(dead_code)]
    pub fn full_transparency() -> Self {
        Self {
            transparency: TransparencyMode::All,
            ..Self::default()
        }
    }
    /// Create a config for opaque checking (no unfolding).
    #[allow(dead_code)]
    pub fn opaque() -> Self {
        Self {
            lazy_delta: false,
            transparency: TransparencyMode::None,
            ..Self::default()
        }
    }
    /// Create a config with proof irrelevance disabled.
    #[allow(dead_code)]
    pub fn no_proof_irrelevance() -> Self {
        Self {
            proof_irrelevance: false,
            ..Self::default()
        }
    }
}
/// A dependency closure builder (transitive closure via BFS).
#[allow(dead_code)]
pub struct TransitiveClosure {
    adj: Vec<Vec<usize>>,
    n: usize,
}
#[allow(dead_code)]
impl TransitiveClosure {
    /// Creates a transitive closure builder for `n` nodes.
    pub fn new(n: usize) -> Self {
        Self {
            adj: vec![Vec::new(); n],
            n,
        }
    }
    /// Adds a direct edge.
    pub fn add_edge(&mut self, from: usize, to: usize) {
        if from < self.n {
            self.adj[from].push(to);
        }
    }
    /// Computes all nodes reachable from `start` (including `start`).
    pub fn reachable_from(&self, start: usize) -> Vec<usize> {
        let mut visited = vec![false; self.n];
        let mut queue = std::collections::VecDeque::new();
        queue.push_back(start);
        while let Some(node) = queue.pop_front() {
            if node >= self.n || visited[node] {
                continue;
            }
            visited[node] = true;
            for &next in &self.adj[node] {
                queue.push_back(next);
            }
        }
        (0..self.n).filter(|&i| visited[i]).collect()
    }
    /// Returns `true` if `from` can transitively reach `to`.
    pub fn can_reach(&self, from: usize, to: usize) -> bool {
        self.reachable_from(from).contains(&to)
    }
}
/// Simple trie for efficient string prefix lookup.
#[allow(dead_code)]
#[derive(Debug, Clone, Default)]
pub struct StringTrie {
    pub(super) children: std::collections::HashMap<char, StringTrie>,
    is_end: bool,
    pub(super) value: Option<String>,
}
impl StringTrie {
    /// Create a new empty trie.
    #[allow(dead_code)]
    pub fn new() -> Self {
        Self::default()
    }
    /// Insert a string into the trie.
    #[allow(dead_code)]
    pub fn insert(&mut self, s: &str) {
        let mut node = self;
        for c in s.chars() {
            node = node.children.entry(c).or_default();
        }
        node.is_end = true;
        node.value = Some(s.to_string());
    }
    /// Check if a string is in the trie.
    #[allow(dead_code)]
    pub fn contains(&self, s: &str) -> bool {
        let mut node = self;
        for c in s.chars() {
            match node.children.get(&c) {
                Some(next) => node = next,
                None => return false,
            }
        }
        node.is_end
    }
    /// Find all strings with a given prefix.
    #[allow(dead_code)]
    pub fn starts_with(&self, prefix: &str) -> Vec<String> {
        let mut node = self;
        for c in prefix.chars() {
            match node.children.get(&c) {
                Some(next) => node = next,
                None => return vec![],
            }
        }
        let mut results = Vec::new();
        collect_strings(node, &mut results);
        results
    }
    /// Get the number of strings in the trie.
    #[allow(dead_code)]
    pub fn len(&self) -> usize {
        let mut count = if self.is_end { 1 } else { 0 };
        for child in self.children.values() {
            count += child.len();
        }
        count
    }
    /// Check if the trie is empty.
    #[allow(dead_code)]
    pub fn is_empty(&self) -> bool {
        self.len() == 0
    }
}
/// A window iterator that yields overlapping windows of size `n`.
#[allow(dead_code)]
pub struct WindowIterator<'a, T> {
    pub(super) data: &'a [T],
    pub(super) pos: usize,
    pub(super) window: usize,
}
#[allow(dead_code)]
impl<'a, T> WindowIterator<'a, T> {
    /// Creates a new window iterator.
    pub fn new(data: &'a [T], window: usize) -> Self {
        Self {
            data,
            pos: 0,
            window,
        }
    }
}
/// A token bucket rate limiter.
#[allow(dead_code)]
pub struct TokenBucket {
    capacity: u64,
    tokens: u64,
    refill_per_ms: u64,
    last_refill: std::time::Instant,
}
#[allow(dead_code)]
impl TokenBucket {
    /// Creates a new token bucket.
    pub fn new(capacity: u64, refill_per_ms: u64) -> Self {
        Self {
            capacity,
            tokens: capacity,
            refill_per_ms,
            last_refill: std::time::Instant::now(),
        }
    }
    /// Attempts to consume `n` tokens.  Returns `true` on success.
    pub fn try_consume(&mut self, n: u64) -> bool {
        self.refill();
        if self.tokens >= n {
            self.tokens -= n;
            true
        } else {
            false
        }
    }
    fn refill(&mut self) {
        let now = std::time::Instant::now();
        let elapsed_ms = now.duration_since(self.last_refill).as_millis() as u64;
        if elapsed_ms > 0 {
            let new_tokens = elapsed_ms * self.refill_per_ms;
            self.tokens = (self.tokens + new_tokens).min(self.capacity);
            self.last_refill = now;
        }
    }
    /// Returns the number of currently available tokens.
    pub fn available(&self) -> u64 {
        self.tokens
    }
    /// Returns the bucket capacity.
    pub fn capacity(&self) -> u64 {
        self.capacity
    }
}
/// A set of rewrite rules.
#[allow(dead_code)]
pub struct RewriteRuleSet {
    rules: Vec<RewriteRule>,
}
#[allow(dead_code)]
impl RewriteRuleSet {
    /// Creates an empty rule set.
    pub fn new() -> Self {
        Self { rules: Vec::new() }
    }
    /// Adds a rule.
    pub fn add(&mut self, rule: RewriteRule) {
        self.rules.push(rule);
    }
    /// Returns the number of rules.
    pub fn len(&self) -> usize {
        self.rules.len()
    }
    /// Returns `true` if the set is empty.
    pub fn is_empty(&self) -> bool {
        self.rules.is_empty()
    }
    /// Returns all conditional rules.
    pub fn conditional_rules(&self) -> Vec<&RewriteRule> {
        self.rules.iter().filter(|r| r.conditional).collect()
    }
    /// Returns all unconditional rules.
    pub fn unconditional_rules(&self) -> Vec<&RewriteRule> {
        self.rules.iter().filter(|r| !r.conditional).collect()
    }
    /// Looks up a rule by name.
    pub fn get(&self, name: &str) -> Option<&RewriteRule> {
        self.rules.iter().find(|r| r.name == name)
    }
}
/// A simple directed acyclic graph.
#[allow(dead_code)]
pub struct SimpleDag {
    /// `edges[i]` is the list of direct successors of node `i`.
    edges: Vec<Vec<usize>>,
}
#[allow(dead_code)]
impl SimpleDag {
    /// Creates a DAG with `n` nodes and no edges.
    pub fn new(n: usize) -> Self {
        Self {
            edges: vec![Vec::new(); n],
        }
    }
    /// Adds an edge from `from` to `to`.
    pub fn add_edge(&mut self, from: usize, to: usize) {
        if from < self.edges.len() {
            self.edges[from].push(to);
        }
    }
    /// Returns the successors of `node`.
    pub fn successors(&self, node: usize) -> &[usize] {
        self.edges.get(node).map(|v| v.as_slice()).unwrap_or(&[])
    }
    /// Returns `true` if `from` can reach `to` via DFS.
    pub fn can_reach(&self, from: usize, to: usize) -> bool {
        let mut visited = vec![false; self.edges.len()];
        self.dfs(from, to, &mut visited)
    }
    fn dfs(&self, cur: usize, target: usize, visited: &mut Vec<bool>) -> bool {
        if cur == target {
            return true;
        }
        if cur >= visited.len() || visited[cur] {
            return false;
        }
        visited[cur] = true;
        for &next in self.successors(cur) {
            if self.dfs(next, target, visited) {
                return true;
            }
        }
        false
    }
    /// Returns the topological order of nodes, or `None` if a cycle is detected.
    pub fn topological_sort(&self) -> Option<Vec<usize>> {
        let n = self.edges.len();
        let mut in_degree = vec![0usize; n];
        for succs in &self.edges {
            for &s in succs {
                if s < n {
                    in_degree[s] += 1;
                }
            }
        }
        let mut queue: std::collections::VecDeque<usize> =
            (0..n).filter(|&i| in_degree[i] == 0).collect();
        let mut order = Vec::new();
        while let Some(node) = queue.pop_front() {
            order.push(node);
            for &s in self.successors(node) {
                if s < n {
                    in_degree[s] -= 1;
                    if in_degree[s] == 0 {
                        queue.push_back(s);
                    }
                }
            }
        }
        if order.len() == n {
            Some(order)
        } else {
            None
        }
    }
    /// Returns the number of nodes.
    pub fn num_nodes(&self) -> usize {
        self.edges.len()
    }
}
/// A flat list of substitution pairs `(from, to)`.
#[allow(dead_code)]
pub struct FlatSubstitution {
    pairs: Vec<(String, String)>,
}
#[allow(dead_code)]
impl FlatSubstitution {
    /// Creates an empty substitution.
    pub fn new() -> Self {
        Self { pairs: Vec::new() }
    }
    /// Adds a pair.
    pub fn add(&mut self, from: impl Into<String>, to: impl Into<String>) {
        self.pairs.push((from.into(), to.into()));
    }
    /// Applies all substitutions to `s` (leftmost-first order).
    pub fn apply(&self, s: &str) -> String {
        let mut result = s.to_string();
        for (from, to) in &self.pairs {
            result = result.replace(from.as_str(), to.as_str());
        }
        result
    }
    /// Returns the number of pairs.
    pub fn len(&self) -> usize {
        self.pairs.len()
    }
    /// Returns `true` if empty.
    pub fn is_empty(&self) -> bool {
        self.pairs.is_empty()
    }
}
/// Represents a rewrite rule `lhs → rhs`.
#[allow(dead_code)]
#[allow(missing_docs)]
pub struct RewriteRule {
    /// The name of the rule.
    pub name: String,
    /// A string representation of the LHS pattern.
    pub lhs: String,
    /// A string representation of the RHS.
    pub rhs: String,
    /// Whether this is a conditional rule (has side conditions).
    pub conditional: bool,
}
#[allow(dead_code)]
impl RewriteRule {
    /// Creates an unconditional rewrite rule.
    pub fn unconditional(
        name: impl Into<String>,
        lhs: impl Into<String>,
        rhs: impl Into<String>,
    ) -> Self {
        Self {
            name: name.into(),
            lhs: lhs.into(),
            rhs: rhs.into(),
            conditional: false,
        }
    }
    /// Creates a conditional rewrite rule.
    pub fn conditional(
        name: impl Into<String>,
        lhs: impl Into<String>,
        rhs: impl Into<String>,
    ) -> Self {
        Self {
            name: name.into(),
            lhs: lhs.into(),
            rhs: rhs.into(),
            conditional: true,
        }
    }
    /// Returns a textual representation.
    pub fn display(&self) -> String {
        format!("{}: {} → {}", self.name, self.lhs, self.rhs)
    }
}
/// A non-empty list (at least one element guaranteed).
#[allow(dead_code)]
pub struct NonEmptyVec<T> {
    head: T,
    tail: Vec<T>,
}
#[allow(dead_code)]
impl<T> NonEmptyVec<T> {
    /// Creates a non-empty vec with a single element.
    pub fn singleton(val: T) -> Self {
        Self {
            head: val,
            tail: Vec::new(),
        }
    }
    /// Pushes an element.
    pub fn push(&mut self, val: T) {
        self.tail.push(val);
    }
    /// Returns a reference to the first element.
    pub fn first(&self) -> &T {
        &self.head
    }
    /// Returns a reference to the last element.
    pub fn last(&self) -> &T {
        self.tail.last().unwrap_or(&self.head)
    }
    /// Returns the number of elements.
    pub fn len(&self) -> usize {
        1 + self.tail.len()
    }
    /// Returns whether the collection is empty.
    pub fn is_empty(&self) -> bool {
        self.len() == 0
    }
    /// Returns all elements as a Vec.
    pub fn to_vec(&self) -> Vec<&T> {
        let mut v = vec![&self.head];
        v.extend(self.tail.iter());
        v
    }
}
/// A fixed-size sliding window that computes a running sum.
#[allow(dead_code)]
pub struct SlidingSum {
    window: Vec<f64>,
    capacity: usize,
    pos: usize,
    sum: f64,
    count: usize,
}
#[allow(dead_code)]
impl SlidingSum {
    /// Creates a sliding sum with the given window size.
    pub fn new(capacity: usize) -> Self {
        Self {
            window: vec![0.0; capacity],
            capacity,
            pos: 0,
            sum: 0.0,
            count: 0,
        }
    }
    /// Adds a value to the window, removing the oldest if full.
    pub fn push(&mut self, val: f64) {
        let oldest = self.window[self.pos];
        self.sum -= oldest;
        self.sum += val;
        self.window[self.pos] = val;
        self.pos = (self.pos + 1) % self.capacity;
        if self.count < self.capacity {
            self.count += 1;
        }
    }
    /// Returns the current window sum.
    pub fn sum(&self) -> f64 {
        self.sum
    }
    /// Returns the window mean, or `None` if empty.
    pub fn mean(&self) -> Option<f64> {
        if self.count == 0 {
            None
        } else {
            Some(self.sum / self.count as f64)
        }
    }
    /// Returns the current window size (number of valid elements).
    pub fn count(&self) -> usize {
        self.count
    }
}
/// Definitional equality checker with full optimizations.
pub struct DefEqChecker<'env> {
    env: &'env Environment,
    reducer: Reducer,
    cache: HashMap<(Expr, Expr), bool>,
    equiv_manager: EquivManager,
    proof_irrelevance: bool,
}
impl<'env> DefEqChecker<'env> {
    /// Create a new definitional equality checker.
    pub fn new(env: &'env Environment) -> Self {
        Self {
            env,
            reducer: Reducer::new(),
            cache: HashMap::new(),
            equiv_manager: EquivManager::new(),
            proof_irrelevance: true,
        }
    }
    /// Disable proof irrelevance for this checker.
    pub fn set_proof_irrelevance(&mut self, enabled: bool) {
        self.proof_irrelevance = enabled;
    }
    /// Set the transparency mode for this checker.
    pub fn set_transparency(&mut self, mode: TransparencyMode) {
        self.reducer.set_transparency(mode);
        self.cache.clear();
        self.equiv_manager.clear();
    }
    /// Check if two expressions are definitionally equal.
    pub fn is_def_eq(&mut self, t: &Expr, s: &Expr) -> bool {
        if t == s {
            return true;
        }
        if self.equiv_manager.is_equiv(t, s) {
            return true;
        }
        if self.equiv_manager.is_failure(t, s) {
            return false;
        }
        let key = (t.clone(), s.clone());
        if let Some(&result) = self.cache.get(&key) {
            return result;
        }
        let result = self.is_def_eq_core(t, s);
        self.cache.insert(key, result);
        if result {
            self.equiv_manager.add_equiv(t, s);
        } else {
            self.equiv_manager.add_failure(t, s);
        }
        result
    }
    fn is_def_eq_core(&mut self, t: &Expr, s: &Expr) -> bool {
        let t_whnf = self.reducer.whnf_env(t, self.env);
        let s_whnf = self.reducer.whnf_env(s, self.env);
        if t_whnf == s_whnf {
            return true;
        }
        if self.is_proof_irrelevant_eq(&t_whnf, &s_whnf) {
            return true;
        }
        match (&t_whnf, &s_whnf) {
            (Expr::Sort(l1), Expr::Sort(l2)) => level::is_equivalent(l1, l2),
            (Expr::BVar(i1), Expr::BVar(i2)) => i1 == i2,
            (Expr::FVar(id1), Expr::FVar(id2)) => id1 == id2,
            (Expr::Const(n1, ls1), Expr::Const(n2, ls2)) => {
                n1 == n2
                    && ls1.len() == ls2.len()
                    && ls1
                        .iter()
                        .zip(ls2.iter())
                        .all(|(l1, l2)| level::is_equivalent(l1, l2))
            }
            (Expr::App(f1, a1), Expr::App(f2, a2)) => {
                if self.is_def_eq_app(&t_whnf, &s_whnf) {
                    return true;
                }
                self.is_def_eq(f1, f2) && self.is_def_eq(a1, a2)
            }
            (Expr::Lam(_, _, ty1, b1), Expr::Lam(_, _, ty2, b2)) => {
                self.is_def_eq(ty1, ty2) && self.is_def_eq(b1, b2)
            }
            (Expr::Pi(_, _, ty1, b1), Expr::Pi(_, _, ty2, b2)) => {
                self.is_def_eq(ty1, ty2) && self.is_def_eq(b1, b2)
            }
            (Expr::Let(_, ty1, v1, b1), Expr::Let(_, ty2, v2, b2)) => {
                self.is_def_eq(ty1, ty2) && self.is_def_eq(v1, v2) && self.is_def_eq(b1, b2)
            }
            (Expr::Lit(l1), Expr::Lit(l2)) => l1 == l2,
            (Expr::Proj(n1, i1, e1), Expr::Proj(n2, i2, e2)) => {
                n1 == n2 && i1 == i2 && self.is_def_eq(e1, e2)
            }
            (Expr::Lam(_, _, _, _), _) => self.try_eta_lhs(&t_whnf, &s_whnf),
            (_, Expr::Lam(_, _, _, _)) => self.try_eta_rhs(&t_whnf, &s_whnf),
            _ => self.try_lazy_delta(&t_whnf, &s_whnf),
        }
    }
    /// Try lazy delta reduction: unfold one side at a time.
    ///
    /// When comparing `f a1 ... an` with `g b1 ... bm` where f and g
    /// are both definitions, unfold the one with lower height first.
    fn try_lazy_delta(&mut self, t: &Expr, s: &Expr) -> bool {
        let t_head = get_app_fn(t);
        let s_head = get_app_fn(s);
        let t_hint = self.get_hint(t_head);
        let s_hint = self.get_hint(s_head);
        match (t_hint, s_hint) {
            (Some(th), Some(sh)) => {
                if th.height() <= sh.height() {
                    if let Some(t_unfolded) = self.unfold_definition(t) {
                        let t_whnf = self.reducer.whnf_env(&t_unfolded, self.env);
                        return self.is_def_eq(&t_whnf, s);
                    }
                }
                if let Some(s_unfolded) = self.unfold_definition(s) {
                    let s_whnf = self.reducer.whnf_env(&s_unfolded, self.env);
                    return self.is_def_eq(t, &s_whnf);
                }
                false
            }
            (Some(_), None) => {
                if let Some(t_unfolded) = self.unfold_definition(t) {
                    let t_whnf = self.reducer.whnf_env(&t_unfolded, self.env);
                    return self.is_def_eq(&t_whnf, s);
                }
                false
            }
            (None, Some(_)) => {
                if let Some(s_unfolded) = self.unfold_definition(s) {
                    let s_whnf = self.reducer.whnf_env(&s_unfolded, self.env);
                    return self.is_def_eq(t, &s_whnf);
                }
                false
            }
            (None, None) => false,
        }
    }
    /// Get the reducibility hint for an expression head.
    fn get_hint(&self, head: &Expr) -> Option<ReducibilityHint> {
        if let Expr::Const(name, _) = head {
            if let Some(ci) = self.env.find(name) {
                let hint = ci.reducibility_hint();
                if hint.should_unfold() {
                    return Some(hint);
                }
            }
        }
        None
    }
    /// Try to unfold a definition at the head of an expression.
    fn unfold_definition(&self, expr: &Expr) -> Option<Expr> {
        let head = get_app_fn(expr);
        if let Expr::Const(name, levels) = head {
            if let Some(ci) = self.env.find(name) {
                if let Some(val) = ci.value() {
                    let val_inst = if ci.level_params().is_empty() || levels.is_empty() {
                        val.clone()
                    } else {
                        crate::instantiate::instantiate_type_lparams(val, ci.level_params(), levels)
                    };
                    let args: Vec<Expr> = get_app_args(expr).into_iter().cloned().collect();
                    return Some(crate::expr_util::mk_app(val_inst, &args));
                }
            }
        }
        None
    }
    /// Try structural application equality.
    ///
    /// Compare `f a1 ... an` with `g b1 ... bn` by comparing
    /// the heads and all arguments.
    fn is_def_eq_app(&mut self, t: &Expr, s: &Expr) -> bool {
        let t_head = get_app_fn(t);
        let s_head = get_app_fn(s);
        let t_args = get_app_args(t);
        let s_args = get_app_args(s);
        if t_args.len() != s_args.len() {
            return false;
        }
        if !self.is_def_eq(t_head, s_head) {
            return false;
        }
        t_args
            .iter()
            .zip(s_args.iter())
            .all(|(a, b)| self.is_def_eq(a, b))
    }
    /// Quickly infer the type of a term without full elaboration.
    ///
    /// Handles the common structural cases needed for proof irrelevance:
    /// constants, applications of Pi-typed functions, Sort, and literals.
    /// Returns `None` for cases that require a full type checker (e.g. BVar, FVar).
    fn quick_infer_type(&mut self, expr: &Expr) -> Option<Expr> {
        match expr {
            Expr::Sort(l) => Some(Expr::Sort(crate::level::Level::succ(l.clone()))),
            Expr::Lit(crate::Literal::Nat(_)) => Some(Expr::Const(crate::Name::str("Nat"), vec![])),
            Expr::Lit(crate::Literal::Str(_)) => {
                Some(Expr::Const(crate::Name::str("String"), vec![]))
            }
            Expr::Const(name, levels) => {
                let ci = self.env.find(name)?;
                let raw_ty = ci.ty().clone();
                let params = ci.level_params().to_vec();
                if params.is_empty() || levels.is_empty() {
                    Some(raw_ty)
                } else {
                    Some(crate::instantiate::instantiate_type_lparams(
                        &raw_ty, &params, levels,
                    ))
                }
            }
            Expr::App(f, a) => {
                let f_ty = self.quick_infer_type(f)?;
                let f_ty_whnf = self.reducer.whnf_env(&f_ty, self.env);
                if let Expr::Pi(_, _, _, body) = f_ty_whnf {
                    Some(crate::subst::instantiate(&body, a))
                } else {
                    None
                }
            }
            Expr::Lam(bi, name, dom, body) => {
                let body_ty = self.quick_infer_type(body)?;
                Some(Expr::Pi(*bi, name.clone(), dom.clone(), Box::new(body_ty)))
            }
            Expr::Pi(_, _, dom, cod) => {
                let dom_ty = self.quick_infer_type(dom)?;
                let cod_ty = self.quick_infer_type(cod)?;
                let dom_whnf = self.reducer.whnf_env(&dom_ty, self.env);
                let cod_whnf = self.reducer.whnf_env(&cod_ty, self.env);
                match (dom_whnf, cod_whnf) {
                    (Expr::Sort(l1), Expr::Sort(l2)) => {
                        Some(Expr::Sort(crate::level::Level::imax(l1, l2)))
                    }
                    _ => None,
                }
            }
            Expr::Let(_, _ty, val, body) => {
                let body_subst = crate::subst::instantiate(body, val);
                self.quick_infer_type(&body_subst)
            }
            _ => None,
        }
    }
    /// Check proof irrelevance: two proofs of the same Prop are definitionally equal.
    ///
    /// Two terms `t` and `s` are proof-irrelevantly equal when:
    /// - Both have types that reduce to `Sort 0` (i.e., they live in `Prop`)
    /// - Their types are definitionally equal (they prove the same proposition)
    fn is_proof_irrelevant_eq(&mut self, t: &Expr, s: &Expr) -> bool {
        if !self.proof_irrelevance {
            return false;
        }
        let ty_t = match self.quick_infer_type(t) {
            Some(ty) => ty,
            None => return false,
        };
        let ty_ty_t = match self.quick_infer_type(&ty_t) {
            Some(ty) => ty,
            None => return false,
        };
        let ty_ty_t_whnf = self.reducer.whnf_env(&ty_ty_t, self.env);
        if !matches!(& ty_ty_t_whnf, Expr::Sort(l) if l.is_zero()) {
            return false;
        }
        let ty_s = match self.quick_infer_type(s) {
            Some(ty) => ty,
            None => return false,
        };
        let ty_ty_s = match self.quick_infer_type(&ty_s) {
            Some(ty) => ty,
            None => return false,
        };
        let ty_ty_s_whnf = self.reducer.whnf_env(&ty_ty_s, self.env);
        if !matches!(& ty_ty_s_whnf, Expr::Sort(l) if l.is_zero()) {
            return false;
        }
        let ty_t_whnf = self.reducer.whnf_env(&ty_t, self.env);
        let ty_s_whnf = self.reducer.whnf_env(&ty_s, self.env);
        self.is_def_eq(&ty_t_whnf, &ty_s_whnf)
    }
    /// Try eta-expansion for left-side lambda.
    ///
    /// `λ x. f x` =?= `g` when `f` doesn't use `x`, then `f =?= g`
    fn try_eta_lhs(&mut self, t: &Expr, s: &Expr) -> bool {
        if let Expr::Lam(_, _, _, body) = t {
            if let Expr::App(f, a) = body.as_ref() {
                if let Expr::BVar(0) = **a {
                    if !has_loose_bvar(f, 0) {
                        let f_shifted =
                            crate::subst::instantiate(f, &Expr::FVar(crate::FVarId(u64::MAX)));
                        return self.is_def_eq(&f_shifted, s);
                    }
                }
            }
        }
        false
    }
    /// Try eta-expansion for right-side lambda.
    fn try_eta_rhs(&mut self, t: &Expr, s: &Expr) -> bool {
        if let Expr::Lam(_, _, _, body) = s {
            if let Expr::App(f, a) = body.as_ref() {
                if let Expr::BVar(0) = **a {
                    if !has_loose_bvar(f, 0) {
                        let f_shifted =
                            crate::subst::instantiate(f, &Expr::FVar(crate::FVarId(u64::MAX)));
                        return self.is_def_eq(t, &f_shifted);
                    }
                }
            }
        }
        false
    }
}
/// A simple key-value store backed by a sorted Vec for small maps.
#[allow(dead_code)]
pub struct SmallMap<K: Ord + Clone, V: Clone> {
    entries: Vec<(K, V)>,
}
#[allow(dead_code)]
impl<K: Ord + Clone, V: Clone> SmallMap<K, V> {
    /// Creates a new empty small map.
    pub fn new() -> Self {
        Self {
            entries: Vec::new(),
        }
    }
    /// Inserts or replaces the value for `key`.
    pub fn insert(&mut self, key: K, val: V) {
        match self.entries.binary_search_by_key(&&key, |(k, _)| k) {
            Ok(i) => self.entries[i].1 = val,
            Err(i) => self.entries.insert(i, (key, val)),
        }
    }
    /// Returns the value for `key`, or `None`.
    pub fn get(&self, key: &K) -> Option<&V> {
        self.entries
            .binary_search_by_key(&key, |(k, _)| k)
            .ok()
            .map(|i| &self.entries[i].1)
    }
    /// Returns the number of entries.
    pub fn len(&self) -> usize {
        self.entries.len()
    }
    /// Returns `true` if empty.
    pub fn is_empty(&self) -> bool {
        self.entries.is_empty()
    }
    /// Returns all keys.
    pub fn keys(&self) -> Vec<&K> {
        self.entries.iter().map(|(k, _)| k).collect()
    }
    /// Returns all values.
    pub fn values(&self) -> Vec<&V> {
        self.entries.iter().map(|(_, v)| v).collect()
    }
}