chore: checkpoint before Python removal

vendor/indexmap/src/map/entry.rs

@@ -0,0 +1,313 @@
+use crate::inner::{Core, OccupiedEntry, VacantEntry};
+use crate::Bucket;
+use core::{fmt, mem};
+
+/// Entry for an existing key-value pair in an [`IndexMap`][crate::IndexMap]
+/// or a vacant location to insert one.
+pub enum Entry<'a, K, V> {
+    /// Existing slot with equivalent key.
+    Occupied(OccupiedEntry<'a, K, V>),
+    /// Vacant slot (no equivalent key in the map).
+    Vacant(VacantEntry<'a, K, V>),
+}
+
+impl<'a, K, V> Entry<'a, K, V> {
+    /// Return the index where the key-value pair exists or will be inserted.
+    pub fn index(&self) -> usize {
+        match self {
+            Entry::Occupied(entry) => entry.index(),
+            Entry::Vacant(entry) => entry.index(),
+        }
+    }
+
+    /// Sets the value of the entry (after inserting if vacant), and returns an `OccupiedEntry`.
+    ///
+    /// Computes in **O(1)** time (amortized average).
+    pub fn insert_entry(self, value: V) -> OccupiedEntry<'a, K, V> {
+        match self {
+            Entry::Occupied(mut entry) => {
+                entry.insert(value);
+                entry
+            }
+            Entry::Vacant(entry) => entry.insert_entry(value),
+        }
+    }
+
+    /// Inserts the given default value in the entry if it is vacant and returns a mutable
+    /// reference to it. Otherwise a mutable reference to an already existent value is returned.
+    ///
+    /// Computes in **O(1)** time (amortized average).
+    pub fn or_insert(self, default: V) -> &'a mut V {
+        match self {
+            Entry::Occupied(entry) => entry.into_mut(),
+            Entry::Vacant(entry) => entry.insert(default),
+        }
+    }
+
+    /// Inserts the result of the `call` function in the entry if it is vacant and returns a mutable
+    /// reference to it. Otherwise a mutable reference to an already existent value is returned.
+    ///
+    /// Computes in **O(1)** time (amortized average).
+    pub fn or_insert_with<F>(self, call: F) -> &'a mut V
+    where
+        F: FnOnce() -> V,
+    {
+        match self {
+            Entry::Occupied(entry) => entry.into_mut(),
+            Entry::Vacant(entry) => entry.insert(call()),
+        }
+    }
+
+    /// Inserts the result of the `call` function with a reference to the entry's key if it is
+    /// vacant, and returns a mutable reference to the new value. Otherwise a mutable reference to
+    /// an already existent value is returned.
+    ///
+    /// Computes in **O(1)** time (amortized average).
+    pub fn or_insert_with_key<F>(self, call: F) -> &'a mut V
+    where
+        F: FnOnce(&K) -> V,
+    {
+        match self {
+            Entry::Occupied(entry) => entry.into_mut(),
+            Entry::Vacant(entry) => {
+                let value = call(entry.key());
+                entry.insert(value)
+            }
+        }
+    }
+
+    /// Gets a reference to the entry's key, either within the map if occupied,
+    /// or else the new key that was used to find the entry.
+    pub fn key(&self) -> &K {
+        match *self {
+            Entry::Occupied(ref entry) => entry.key(),
+            Entry::Vacant(ref entry) => entry.key(),
+        }
+    }
+
+    /// Modifies the entry if it is occupied.
+    pub fn and_modify<F>(mut self, f: F) -> Self
+    where
+        F: FnOnce(&mut V),
+    {
+        if let Entry::Occupied(entry) = &mut self {
+            f(entry.get_mut());
+        }
+        self
+    }
+
+    /// Inserts a default-constructed value in the entry if it is vacant and returns a mutable
+    /// reference to it. Otherwise a mutable reference to an already existent value is returned.
+    ///
+    /// Computes in **O(1)** time (amortized average).
+    pub fn or_default(self) -> &'a mut V
+    where
+        V: Default,
+    {
+        match self {
+            Entry::Occupied(entry) => entry.into_mut(),
+            Entry::Vacant(entry) => entry.insert(V::default()),
+        }
+    }
+}
+
+impl<K: fmt::Debug, V: fmt::Debug> fmt::Debug for Entry<'_, K, V> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let mut tuple = f.debug_tuple("Entry");
+        match self {
+            Entry::Vacant(v) => tuple.field(v),
+            Entry::Occupied(o) => tuple.field(o),
+        };
+        tuple.finish()
+    }
+}
+
+impl<K: fmt::Debug, V: fmt::Debug> fmt::Debug for OccupiedEntry<'_, K, V> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("OccupiedEntry")
+            .field("key", self.key())
+            .field("value", self.get())
+            .finish()
+    }
+}
+
+impl<K: fmt::Debug, V> fmt::Debug for VacantEntry<'_, K, V> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_tuple("VacantEntry").field(self.key()).finish()
+    }
+}
+
+/// A view into an occupied entry in an [`IndexMap`][crate::IndexMap] obtained by index.
+///
+/// This `struct` is created from the [`get_index_entry`][crate::IndexMap::get_index_entry] method.
+pub struct IndexedEntry<'a, K, V> {
+    map: &'a mut Core<K, V>,
+    // We have a mutable reference to the map, which keeps the index
+    // valid and pointing to the correct entry.
+    index: usize,
+}
+
+impl<'a, K, V> IndexedEntry<'a, K, V> {
+    pub(crate) fn new(map: &'a mut Core<K, V>, index: usize) -> Option<Self> {
+        if index < map.len() {
+            Some(Self { map, index })
+        } else {
+            None
+        }
+    }
+
+    /// Return the index of the key-value pair
+    #[inline]
+    pub fn index(&self) -> usize {
+        self.index
+    }
+
+    pub(crate) fn into_core(self) -> &'a mut Core<K, V> {
+        self.map
+    }
+
+    fn get_bucket(&self) -> &Bucket<K, V> {
+        &self.map.as_entries()[self.index]
+    }
+
+    fn get_bucket_mut(&mut self) -> &mut Bucket<K, V> {
+        &mut self.map.as_entries_mut()[self.index]
+    }
+
+    fn into_bucket(self) -> &'a mut Bucket<K, V> {
+        &mut self.map.as_entries_mut()[self.index]
+    }
+
+    /// Gets a reference to the entry's key in the map.
+    pub fn key(&self) -> &K {
+        &self.get_bucket().key
+    }
+
+    pub(super) fn key_mut(&mut self) -> &mut K {
+        &mut self.get_bucket_mut().key
+    }
+
+    /// Gets a reference to the entry's value in the map.
+    pub fn get(&self) -> &V {
+        &self.get_bucket().value
+    }
+
+    /// Gets a mutable reference to the entry's value in the map.
+    ///
+    /// If you need a reference which may outlive the destruction of the
+    /// `IndexedEntry` value, see [`into_mut`][Self::into_mut].
+    pub fn get_mut(&mut self) -> &mut V {
+        &mut self.get_bucket_mut().value
+    }
+
+    /// Sets the value of the entry to `value`, and returns the entry's old value.
+    pub fn insert(&mut self, value: V) -> V {
+        mem::replace(self.get_mut(), value)
+    }
+
+    /// Converts into a mutable reference to the entry's value in the map,
+    /// with a lifetime bound to the map itself.
+    pub fn into_mut(self) -> &'a mut V {
+        &mut self.into_bucket().value
+    }
+
+    /// Remove and return the key, value pair stored in the map for this entry
+    ///
+    /// Like [`Vec::swap_remove`][alloc::vec::Vec::swap_remove], the pair is removed by swapping it
+    /// with the last element of the map and popping it off.
+    /// **This perturbs the position of what used to be the last element!**
+    ///
+    /// Computes in **O(1)** time (average).
+    pub fn swap_remove_entry(self) -> (K, V) {
+        self.map.swap_remove_index(self.index).unwrap()
+    }
+
+    /// Remove and return the key, value pair stored in the map for this entry
+    ///
+    /// Like [`Vec::remove`][alloc::vec::Vec::remove], the pair is removed by shifting all of the
+    /// elements that follow it, preserving their relative order.
+    /// **This perturbs the index of all of those elements!**
+    ///
+    /// Computes in **O(n)** time (average).
+    pub fn shift_remove_entry(self) -> (K, V) {
+        self.map.shift_remove_index(self.index).unwrap()
+    }
+
+    /// Remove the key, value pair stored in the map for this entry, and return the value.
+    ///
+    /// Like [`Vec::swap_remove`][alloc::vec::Vec::swap_remove], the pair is removed by swapping it
+    /// with the last element of the map and popping it off.
+    /// **This perturbs the position of what used to be the last element!**
+    ///
+    /// Computes in **O(1)** time (average).
+    pub fn swap_remove(self) -> V {
+        self.swap_remove_entry().1
+    }
+
+    /// Remove the key, value pair stored in the map for this entry, and return the value.
+    ///
+    /// Like [`Vec::remove`][alloc::vec::Vec::remove], the pair is removed by shifting all of the
+    /// elements that follow it, preserving their relative order.
+    /// **This perturbs the index of all of those elements!**
+    ///
+    /// Computes in **O(n)** time (average).
+    pub fn shift_remove(self) -> V {
+        self.shift_remove_entry().1
+    }
+
+    /// Moves the position of the entry to a new index
+    /// by shifting all other entries in-between.
+    ///
+    /// This is equivalent to [`IndexMap::move_index`][`crate::IndexMap::move_index`]
+    /// coming `from` the current [`.index()`][Self::index].
+    ///
+    /// * If `self.index() < to`, the other pairs will shift down while the targeted pair moves up.
+    /// * If `self.index() > to`, the other pairs will shift up while the targeted pair moves down.
+    ///
+    /// ***Panics*** if `to` is out of bounds.
+    ///
+    /// Computes in **O(n)** time (average).
+    #[track_caller]
+    pub fn move_index(self, to: usize) {
+        self.map.move_index(self.index, to);
+    }
+
+    /// Swaps the position of entry with another.
+    ///
+    /// This is equivalent to [`IndexMap::swap_indices`][`crate::IndexMap::swap_indices`]
+    /// with the current [`.index()`][Self::index] as one of the two being swapped.
+    ///
+    /// ***Panics*** if the `other` index is out of bounds.
+    ///
+    /// Computes in **O(1)** time (average).
+    #[track_caller]
+    pub fn swap_indices(self, other: usize) {
+        self.map.swap_indices(self.index, other);
+    }
+}
+
+impl<K: fmt::Debug, V: fmt::Debug> fmt::Debug for IndexedEntry<'_, K, V> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("IndexedEntry")
+            .field("index", &self.index)
+            .field("key", self.key())
+            .field("value", self.get())
+            .finish()
+    }
+}
+
+impl<'a, K, V> From<OccupiedEntry<'a, K, V>> for IndexedEntry<'a, K, V> {
+    fn from(other: OccupiedEntry<'a, K, V>) -> Self {
+        Self {
+            index: other.index(),
+            map: other.into_core(),
+        }
+    }
+}
+
+#[test]
+fn assert_send_sync() {
+    fn assert_send_sync<T: Send + Sync>() {}
+    assert_send_sync::<Entry<'_, i32, i32>>();
+    assert_send_sync::<IndexedEntry<'_, i32, i32>>();
+}

vendor/indexmap/src/map/iter.rs

@@ -0,0 +1,894 @@
+use super::{Bucket, HashValue, IndexMap, Slice};
+use crate::inner::{Core, ExtractCore};
+
+use alloc::vec::{self, Vec};
+use core::fmt;
+use core::hash::{BuildHasher, Hash};
+use core::iter::FusedIterator;
+use core::mem::MaybeUninit;
+use core::ops::{Index, RangeBounds};
+use core::slice;
+
+impl<'a, K, V, S> IntoIterator for &'a IndexMap<K, V, S> {
+    type Item = (&'a K, &'a V);
+    type IntoIter = Iter<'a, K, V>;
+
+    fn into_iter(self) -> Self::IntoIter {
+        self.iter()
+    }
+}
+
+impl<'a, K, V, S> IntoIterator for &'a mut IndexMap<K, V, S> {
+    type Item = (&'a K, &'a mut V);
+    type IntoIter = IterMut<'a, K, V>;
+
+    fn into_iter(self) -> Self::IntoIter {
+        self.iter_mut()
+    }
+}
+
+impl<K, V, S> IntoIterator for IndexMap<K, V, S> {
+    type Item = (K, V);
+    type IntoIter = IntoIter<K, V>;
+
+    fn into_iter(self) -> Self::IntoIter {
+        IntoIter::new(self.into_entries())
+    }
+}
+
+/// An iterator over the entries of an [`IndexMap`].
+///
+/// This `struct` is created by the [`IndexMap::iter`] method.
+/// See its documentation for more.
+pub struct Iter<'a, K, V> {
+    iter: slice::Iter<'a, Bucket<K, V>>,
+}
+
+impl<'a, K, V> Iter<'a, K, V> {
+    pub(super) fn new(entries: &'a [Bucket<K, V>]) -> Self {
+        Self {
+            iter: entries.iter(),
+        }
+    }
+
+    /// Returns a slice of the remaining entries in the iterator.
+    pub fn as_slice(&self) -> &'a Slice<K, V> {
+        Slice::from_slice(self.iter.as_slice())
+    }
+}
+
+impl<'a, K, V> Iterator for Iter<'a, K, V> {
+    type Item = (&'a K, &'a V);
+
+    iterator_methods!(Bucket::refs);
+}
+
+impl<K, V> DoubleEndedIterator for Iter<'_, K, V> {
+    double_ended_iterator_methods!(Bucket::refs);
+}
+
+impl<K, V> ExactSizeIterator for Iter<'_, K, V> {
+    fn len(&self) -> usize {
+        self.iter.len()
+    }
+}
+
+impl<K, V> FusedIterator for Iter<'_, K, V> {}
+
+// FIXME(#26925) Remove in favor of `#[derive(Clone)]`
+impl<K, V> Clone for Iter<'_, K, V> {
+    fn clone(&self) -> Self {
+        Iter {
+            iter: self.iter.clone(),
+        }
+    }
+}
+
+impl<K: fmt::Debug, V: fmt::Debug> fmt::Debug for Iter<'_, K, V> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_list().entries(self.clone()).finish()
+    }
+}
+
+impl<K, V> Default for Iter<'_, K, V> {
+    fn default() -> Self {
+        Self { iter: [].iter() }
+    }
+}
+
+/// A mutable iterator over the entries of an [`IndexMap`].
+///
+/// This `struct` is created by the [`IndexMap::iter_mut`] method.
+/// See its documentation for more.
+pub struct IterMut<'a, K, V> {
+    iter: slice::IterMut<'a, Bucket<K, V>>,
+}
+
+impl<'a, K, V> IterMut<'a, K, V> {
+    pub(super) fn new(entries: &'a mut [Bucket<K, V>]) -> Self {
+        Self {
+            iter: entries.iter_mut(),
+        }
+    }
+
+    /// Returns a slice of the remaining entries in the iterator.
+    pub fn as_slice(&self) -> &Slice<K, V> {
+        Slice::from_slice(self.iter.as_slice())
+    }
+
+    /// Returns a mutable slice of the remaining entries in the iterator.
+    ///
+    /// To avoid creating `&mut` references that alias, this is forced to consume the iterator.
+    pub fn into_slice(self) -> &'a mut Slice<K, V> {
+        Slice::from_mut_slice(self.iter.into_slice())
+    }
+}
+
+impl<'a, K, V> Iterator for IterMut<'a, K, V> {
+    type Item = (&'a K, &'a mut V);
+
+    iterator_methods!(Bucket::ref_mut);
+}
+
+impl<K, V> DoubleEndedIterator for IterMut<'_, K, V> {
+    double_ended_iterator_methods!(Bucket::ref_mut);
+}
+
+impl<K, V> ExactSizeIterator for IterMut<'_, K, V> {
+    fn len(&self) -> usize {
+        self.iter.len()
+    }
+}
+
+impl<K, V> FusedIterator for IterMut<'_, K, V> {}
+
+impl<K: fmt::Debug, V: fmt::Debug> fmt::Debug for IterMut<'_, K, V> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let iter = self.iter.as_slice().iter().map(Bucket::refs);
+        f.debug_list().entries(iter).finish()
+    }
+}
+
+impl<K, V> Default for IterMut<'_, K, V> {
+    fn default() -> Self {
+        Self {
+            iter: [].iter_mut(),
+        }
+    }
+}
+
+/// A mutable iterator over the entries of an [`IndexMap`].
+///
+/// This `struct` is created by the [`MutableKeys::iter_mut2`][super::MutableKeys::iter_mut2] method.
+/// See its documentation for more.
+pub struct IterMut2<'a, K, V> {
+    iter: slice::IterMut<'a, Bucket<K, V>>,
+}
+
+impl<'a, K, V> IterMut2<'a, K, V> {
+    pub(super) fn new(entries: &'a mut [Bucket<K, V>]) -> Self {
+        Self {
+            iter: entries.iter_mut(),
+        }
+    }
+
+    /// Returns a slice of the remaining entries in the iterator.
+    pub fn as_slice(&self) -> &Slice<K, V> {
+        Slice::from_slice(self.iter.as_slice())
+    }
+
+    /// Returns a mutable slice of the remaining entries in the iterator.
+    ///
+    /// To avoid creating `&mut` references that alias, this is forced to consume the iterator.
+    pub fn into_slice(self) -> &'a mut Slice<K, V> {
+        Slice::from_mut_slice(self.iter.into_slice())
+    }
+}
+
+impl<'a, K, V> Iterator for IterMut2<'a, K, V> {
+    type Item = (&'a mut K, &'a mut V);
+
+    iterator_methods!(Bucket::muts);
+}
+
+impl<K, V> DoubleEndedIterator for IterMut2<'_, K, V> {
+    double_ended_iterator_methods!(Bucket::muts);
+}
+
+impl<K, V> ExactSizeIterator for IterMut2<'_, K, V> {
+    fn len(&self) -> usize {
+        self.iter.len()
+    }
+}
+
+impl<K, V> FusedIterator for IterMut2<'_, K, V> {}
+
+impl<K: fmt::Debug, V: fmt::Debug> fmt::Debug for IterMut2<'_, K, V> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let iter = self.iter.as_slice().iter().map(Bucket::refs);
+        f.debug_list().entries(iter).finish()
+    }
+}
+
+impl<K, V> Default for IterMut2<'_, K, V> {
+    fn default() -> Self {
+        Self {
+            iter: [].iter_mut(),
+        }
+    }
+}
+
+/// An owning iterator over the entries of an [`IndexMap`].
+///
+/// This `struct` is created by the [`IndexMap::into_iter`] method
+/// (provided by the [`IntoIterator`] trait). See its documentation for more.
+#[derive(Clone)]
+pub struct IntoIter<K, V> {
+    iter: vec::IntoIter<Bucket<K, V>>,
+}
+
+impl<K, V> IntoIter<K, V> {
+    pub(super) fn new(entries: Vec<Bucket<K, V>>) -> Self {
+        Self {
+            iter: entries.into_iter(),
+        }
+    }
+
+    /// Returns a slice of the remaining entries in the iterator.
+    pub fn as_slice(&self) -> &Slice<K, V> {
+        Slice::from_slice(self.iter.as_slice())
+    }
+
+    /// Returns a mutable slice of the remaining entries in the iterator.
+    pub fn as_mut_slice(&mut self) -> &mut Slice<K, V> {
+        Slice::from_mut_slice(self.iter.as_mut_slice())
+    }
+}
+
+impl<K, V> Iterator for IntoIter<K, V> {
+    type Item = (K, V);
+
+    iterator_methods!(Bucket::key_value);
+}
+
+impl<K, V> DoubleEndedIterator for IntoIter<K, V> {
+    double_ended_iterator_methods!(Bucket::key_value);
+}
+
+impl<K, V> ExactSizeIterator for IntoIter<K, V> {
+    fn len(&self) -> usize {
+        self.iter.len()
+    }
+}
+
+impl<K, V> FusedIterator for IntoIter<K, V> {}
+
+impl<K: fmt::Debug, V: fmt::Debug> fmt::Debug for IntoIter<K, V> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let iter = self.iter.as_slice().iter().map(Bucket::refs);
+        f.debug_list().entries(iter).finish()
+    }
+}
+
+impl<K, V> Default for IntoIter<K, V> {
+    fn default() -> Self {
+        Self {
+            iter: Vec::new().into_iter(),
+        }
+    }
+}
+
+/// A draining iterator over the entries of an [`IndexMap`].
+///
+/// This `struct` is created by the [`IndexMap::drain`] method.
+/// See its documentation for more.
+pub struct Drain<'a, K, V> {
+    iter: vec::Drain<'a, Bucket<K, V>>,
+}
+
+impl<'a, K, V> Drain<'a, K, V> {
+    pub(super) fn new(iter: vec::Drain<'a, Bucket<K, V>>) -> Self {
+        Self { iter }
+    }
+
+    /// Returns a slice of the remaining entries in the iterator.
+    pub fn as_slice(&self) -> &Slice<K, V> {
+        Slice::from_slice(self.iter.as_slice())
+    }
+}
+
+impl<K, V> Iterator for Drain<'_, K, V> {
+    type Item = (K, V);
+
+    iterator_methods!(Bucket::key_value);
+}
+
+impl<K, V> DoubleEndedIterator for Drain<'_, K, V> {
+    double_ended_iterator_methods!(Bucket::key_value);
+}
+
+impl<K, V> ExactSizeIterator for Drain<'_, K, V> {
+    fn len(&self) -> usize {
+        self.iter.len()
+    }
+}
+
+impl<K, V> FusedIterator for Drain<'_, K, V> {}
+
+impl<K: fmt::Debug, V: fmt::Debug> fmt::Debug for Drain<'_, K, V> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let iter = self.iter.as_slice().iter().map(Bucket::refs);
+        f.debug_list().entries(iter).finish()
+    }
+}
+
+/// An iterator over the keys of an [`IndexMap`].
+///
+/// This `struct` is created by the [`IndexMap::keys`] method.
+/// See its documentation for more.
+pub struct Keys<'a, K, V> {
+    iter: slice::Iter<'a, Bucket<K, V>>,
+}
+
+impl<'a, K, V> Keys<'a, K, V> {
+    pub(super) fn new(entries: &'a [Bucket<K, V>]) -> Self {
+        Self {
+            iter: entries.iter(),
+        }
+    }
+}
+
+impl<'a, K, V> Iterator for Keys<'a, K, V> {
+    type Item = &'a K;
+
+    iterator_methods!(Bucket::key_ref);
+}
+
+impl<K, V> DoubleEndedIterator for Keys<'_, K, V> {
+    double_ended_iterator_methods!(Bucket::key_ref);
+}
+
+impl<K, V> ExactSizeIterator for Keys<'_, K, V> {
+    fn len(&self) -> usize {
+        self.iter.len()
+    }
+}
+
+impl<K, V> FusedIterator for Keys<'_, K, V> {}
+
+// FIXME(#26925) Remove in favor of `#[derive(Clone)]`
+impl<K, V> Clone for Keys<'_, K, V> {
+    fn clone(&self) -> Self {
+        Keys {
+            iter: self.iter.clone(),
+        }
+    }
+}
+
+impl<K: fmt::Debug, V> fmt::Debug for Keys<'_, K, V> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_list().entries(self.clone()).finish()
+    }
+}
+
+impl<K, V> Default for Keys<'_, K, V> {
+    fn default() -> Self {
+        Self { iter: [].iter() }
+    }
+}
+
+/// Access [`IndexMap`] keys at indexed positions.
+///
+/// While [`Index<usize> for IndexMap`][values] accesses a map's values,
+/// indexing through [`IndexMap::keys`] offers an alternative to access a map's
+/// keys instead.
+///
+/// [values]: IndexMap#impl-Index<usize>-for-IndexMap<K,+V,+S>
+///
+/// Since `Keys` is also an iterator, consuming items from the iterator will
+/// offset the effective indices. Similarly, if `Keys` is obtained from
+/// [`Slice::keys`], indices will be interpreted relative to the position of
+/// that slice.
+///
+/// # Examples
+///
+/// ```
+/// use indexmap::IndexMap;
+///
+/// let mut map = IndexMap::new();
+/// for word in "Lorem ipsum dolor sit amet".split_whitespace() {
+///     map.insert(word.to_lowercase(), word.to_uppercase());
+/// }
+///
+/// assert_eq!(map[0], "LOREM");
+/// assert_eq!(map.keys()[0], "lorem");
+/// assert_eq!(map[1], "IPSUM");
+/// assert_eq!(map.keys()[1], "ipsum");
+///
+/// map.reverse();
+/// assert_eq!(map.keys()[0], "amet");
+/// assert_eq!(map.keys()[1], "sit");
+///
+/// map.sort_keys();
+/// assert_eq!(map.keys()[0], "amet");
+/// assert_eq!(map.keys()[1], "dolor");
+///
+/// // Advancing the iterator will offset the indexing
+/// let mut keys = map.keys();
+/// assert_eq!(keys[0], "amet");
+/// assert_eq!(keys.next().map(|s| &**s), Some("amet"));
+/// assert_eq!(keys[0], "dolor");
+/// assert_eq!(keys[1], "ipsum");
+///
+/// // Slices may have an offset as well
+/// let slice = &map[2..];
+/// assert_eq!(slice[0], "IPSUM");
+/// assert_eq!(slice.keys()[0], "ipsum");
+/// ```
+///
+/// ```should_panic
+/// use indexmap::IndexMap;
+///
+/// let mut map = IndexMap::new();
+/// map.insert("foo", 1);
+/// println!("{:?}", map.keys()[10]); // panics!
+/// ```
+impl<K, V> Index<usize> for Keys<'_, K, V> {
+    type Output = K;
+
+    /// Returns a reference to the key at the supplied `index`.
+    ///
+    /// ***Panics*** if `index` is out of bounds.
+    fn index(&self, index: usize) -> &K {
+        &self.iter.as_slice()[index].key
+    }
+}
+
+/// An owning iterator over the keys of an [`IndexMap`].
+///
+/// This `struct` is created by the [`IndexMap::into_keys`] method.
+/// See its documentation for more.
+pub struct IntoKeys<K, V> {
+    // We eagerly drop the values during construction so we can ignore them in
+    // `Clone`, but we keep uninit values so the bucket's size and alignment
+    // remain the same, and therefore the `Vec` conversion should be in-place.
+    iter: vec::IntoIter<Bucket<K, MaybeUninit<V>>>,
+}
+
+impl<K, V> IntoKeys<K, V> {
+    pub(super) fn new(entries: Vec<Bucket<K, V>>) -> Self {
+        // The original values will be dropped here.
+        // The hash doesn't matter, but "copying" it in-place is free.
+        let entries = entries
+            .into_iter()
+            .map(|Bucket { hash, key, .. }| Bucket {
+                hash,
+                key,
+                value: MaybeUninit::uninit(),
+            })
+            .collect::<Vec<_>>();
+        Self {
+            iter: entries.into_iter(),
+        }
+    }
+}
+
+impl<K: Clone, V> Clone for IntoKeys<K, V> {
+    fn clone(&self) -> Self {
+        let entries = self
+            .iter
+            .as_slice()
+            .iter()
+            .map(|Bucket { key, .. }| Bucket {
+                hash: HashValue(0),
+                key: key.clone(),
+                value: MaybeUninit::uninit(),
+            })
+            .collect::<Vec<_>>();
+        Self {
+            iter: entries.into_iter(),
+        }
+    }
+}
+
+impl<K, V> Iterator for IntoKeys<K, V> {
+    type Item = K;
+
+    iterator_methods!(Bucket::key);
+}
+
+impl<K, V> DoubleEndedIterator for IntoKeys<K, V> {
+    double_ended_iterator_methods!(Bucket::key);
+}
+
+impl<K, V> ExactSizeIterator for IntoKeys<K, V> {
+    fn len(&self) -> usize {
+        self.iter.len()
+    }
+}
+
+impl<K, V> FusedIterator for IntoKeys<K, V> {}
+
+impl<K: fmt::Debug, V> fmt::Debug for IntoKeys<K, V> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let iter = self.iter.as_slice().iter().map(Bucket::key_ref);
+        f.debug_list().entries(iter).finish()
+    }
+}
+
+impl<K, V> Default for IntoKeys<K, V> {
+    fn default() -> Self {
+        Self {
+            iter: Vec::new().into_iter(),
+        }
+    }
+}
+
+/// An iterator over the values of an [`IndexMap`].
+///
+/// This `struct` is created by the [`IndexMap::values`] method.
+/// See its documentation for more.
+pub struct Values<'a, K, V> {
+    iter: slice::Iter<'a, Bucket<K, V>>,
+}
+
+impl<'a, K, V> Values<'a, K, V> {
+    pub(super) fn new(entries: &'a [Bucket<K, V>]) -> Self {
+        Self {
+            iter: entries.iter(),
+        }
+    }
+}
+
+impl<'a, K, V> Iterator for Values<'a, K, V> {
+    type Item = &'a V;
+
+    iterator_methods!(Bucket::value_ref);
+}
+
+impl<K, V> DoubleEndedIterator for Values<'_, K, V> {
+    double_ended_iterator_methods!(Bucket::value_ref);
+}
+
+impl<K, V> ExactSizeIterator for Values<'_, K, V> {
+    fn len(&self) -> usize {
+        self.iter.len()
+    }
+}
+
+impl<K, V> FusedIterator for Values<'_, K, V> {}
+
+// FIXME(#26925) Remove in favor of `#[derive(Clone)]`
+impl<K, V> Clone for Values<'_, K, V> {
+    fn clone(&self) -> Self {
+        Values {
+            iter: self.iter.clone(),
+        }
+    }
+}
+
+impl<K, V: fmt::Debug> fmt::Debug for Values<'_, K, V> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_list().entries(self.clone()).finish()
+    }
+}
+
+impl<K, V> Default for Values<'_, K, V> {
+    fn default() -> Self {
+        Self { iter: [].iter() }
+    }
+}
+
+/// A mutable iterator over the values of an [`IndexMap`].
+///
+/// This `struct` is created by the [`IndexMap::values_mut`] method.
+/// See its documentation for more.
+pub struct ValuesMut<'a, K, V> {
+    iter: slice::IterMut<'a, Bucket<K, V>>,
+}
+
+impl<'a, K, V> ValuesMut<'a, K, V> {
+    pub(super) fn new(entries: &'a mut [Bucket<K, V>]) -> Self {
+        Self {
+            iter: entries.iter_mut(),
+        }
+    }
+}
+
+impl<'a, K, V> Iterator for ValuesMut<'a, K, V> {
+    type Item = &'a mut V;
+
+    iterator_methods!(Bucket::value_mut);
+}
+
+impl<K, V> DoubleEndedIterator for ValuesMut<'_, K, V> {
+    double_ended_iterator_methods!(Bucket::value_mut);
+}
+
+impl<K, V> ExactSizeIterator for ValuesMut<'_, K, V> {
+    fn len(&self) -> usize {
+        self.iter.len()
+    }
+}
+
+impl<K, V> FusedIterator for ValuesMut<'_, K, V> {}
+
+impl<K, V: fmt::Debug> fmt::Debug for ValuesMut<'_, K, V> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let iter = self.iter.as_slice().iter().map(Bucket::value_ref);
+        f.debug_list().entries(iter).finish()
+    }
+}
+
+impl<K, V> Default for ValuesMut<'_, K, V> {
+    fn default() -> Self {
+        Self {
+            iter: [].iter_mut(),
+        }
+    }
+}
+
+/// An owning iterator over the values of an [`IndexMap`].
+///
+/// This `struct` is created by the [`IndexMap::into_values`] method.
+/// See its documentation for more.
+pub struct IntoValues<K, V> {
+    // We eagerly drop the keys during construction so we can ignore them in
+    // `Clone`, but we keep uninit keys so the bucket's size and alignment
+    // remain the same, and therefore the `Vec` conversion should be in-place.
+    iter: vec::IntoIter<Bucket<MaybeUninit<K>, V>>,
+}
+
+impl<K, V> IntoValues<K, V> {
+    pub(super) fn new(entries: Vec<Bucket<K, V>>) -> Self {
+        // The original keys will be dropped here.
+        // The hash doesn't matter, but "copying" it in-place is free.
+        let entries = entries
+            .into_iter()
+            .map(|Bucket { hash, value, .. }| Bucket {
+                hash,
+                key: MaybeUninit::uninit(),
+                value,
+            })
+            .collect::<Vec<_>>();
+        Self {
+            iter: entries.into_iter(),
+        }
+    }
+}
+
+impl<K, V: Clone> Clone for IntoValues<K, V> {
+    fn clone(&self) -> Self {
+        let entries = self
+            .iter
+            .as_slice()
+            .iter()
+            .map(|Bucket { value, .. }| Bucket {
+                hash: HashValue(0),
+                key: MaybeUninit::uninit(),
+                value: value.clone(),
+            })
+            .collect::<Vec<_>>();
+        Self {
+            iter: entries.into_iter(),
+        }
+    }
+}
+
+impl<K, V> Iterator for IntoValues<K, V> {
+    type Item = V;
+
+    iterator_methods!(Bucket::value);
+}
+
+impl<K, V> DoubleEndedIterator for IntoValues<K, V> {
+    double_ended_iterator_methods!(Bucket::value);
+}
+
+impl<K, V> ExactSizeIterator for IntoValues<K, V> {
+    fn len(&self) -> usize {
+        self.iter.len()
+    }
+}
+
+impl<K, V> FusedIterator for IntoValues<K, V> {}
+
+impl<K, V: fmt::Debug> fmt::Debug for IntoValues<K, V> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let iter = self.iter.as_slice().iter().map(Bucket::value_ref);
+        f.debug_list().entries(iter).finish()
+    }
+}
+
+impl<K, V> Default for IntoValues<K, V> {
+    fn default() -> Self {
+        Self {
+            iter: Vec::new().into_iter(),
+        }
+    }
+}
+
+/// A splicing iterator for `IndexMap`.
+///
+/// This `struct` is created by [`IndexMap::splice()`].
+/// See its documentation for more.
+pub struct Splice<'a, I, K, V, S>
+where
+    I: Iterator<Item = (K, V)>,
+    K: Hash + Eq,
+    S: BuildHasher,
+{
+    map: &'a mut IndexMap<K, V, S>,
+    tail: Core<K, V>,
+    drain: vec::IntoIter<Bucket<K, V>>,
+    replace_with: I,
+}
+
+impl<'a, I, K, V, S> Splice<'a, I, K, V, S>
+where
+    I: Iterator<Item = (K, V)>,
+    K: Hash + Eq,
+    S: BuildHasher,
+{
+    #[track_caller]
+    pub(super) fn new<R>(map: &'a mut IndexMap<K, V, S>, range: R, replace_with: I) -> Self
+    where
+        R: RangeBounds<usize>,
+    {
+        let (tail, drain) = map.core.split_splice(range);
+        Self {
+            map,
+            tail,
+            drain,
+            replace_with,
+        }
+    }
+}
+
+impl<I, K, V, S> Drop for Splice<'_, I, K, V, S>
+where
+    I: Iterator<Item = (K, V)>,
+    K: Hash + Eq,
+    S: BuildHasher,
+{
+    fn drop(&mut self) {
+        // Finish draining unconsumed items. We don't strictly *have* to do this
+        // manually, since we already split it into separate memory, but it will
+        // match the drop order of `vec::Splice` items this way.
+        let _ = self.drain.nth(usize::MAX);
+
+        // Now insert all the new items. If a key matches an existing entry, it
+        // keeps the original position and only replaces the value, like `insert`.
+        while let Some((key, value)) = self.replace_with.next() {
+            // Since the tail is disjoint, we can try to update it first,
+            // or else insert (update or append) the primary map.
+            let hash = self.map.hash(&key);
+            if let Some(i) = self.tail.get_index_of(hash, &key) {
+                self.tail.as_entries_mut()[i].value = value;
+            } else {
+                self.map.core.insert_full(hash, key, value);
+            }
+        }
+
+        // Finally, re-append the tail
+        self.map.core.append_unchecked(&mut self.tail);
+    }
+}
+
+impl<I, K, V, S> Iterator for Splice<'_, I, K, V, S>
+where
+    I: Iterator<Item = (K, V)>,
+    K: Hash + Eq,
+    S: BuildHasher,
+{
+    type Item = (K, V);
+
+    fn next(&mut self) -> Option<Self::Item> {
+        self.drain.next().map(Bucket::key_value)
+    }
+
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        self.drain.size_hint()
+    }
+}
+
+impl<I, K, V, S> DoubleEndedIterator for Splice<'_, I, K, V, S>
+where
+    I: Iterator<Item = (K, V)>,
+    K: Hash + Eq,
+    S: BuildHasher,
+{
+    fn next_back(&mut self) -> Option<Self::Item> {
+        self.drain.next_back().map(Bucket::key_value)
+    }
+}
+
+impl<I, K, V, S> ExactSizeIterator for Splice<'_, I, K, V, S>
+where
+    I: Iterator<Item = (K, V)>,
+    K: Hash + Eq,
+    S: BuildHasher,
+{
+    fn len(&self) -> usize {
+        self.drain.len()
+    }
+}
+
+impl<I, K, V, S> FusedIterator for Splice<'_, I, K, V, S>
+where
+    I: Iterator<Item = (K, V)>,
+    K: Hash + Eq,
+    S: BuildHasher,
+{
+}
+
+impl<I, K, V, S> fmt::Debug for Splice<'_, I, K, V, S>
+where
+    I: fmt::Debug + Iterator<Item = (K, V)>,
+    K: fmt::Debug + Hash + Eq,
+    V: fmt::Debug,
+    S: BuildHasher,
+{
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        // Follow `vec::Splice` in only printing the drain and replacement
+        f.debug_struct("Splice")
+            .field("drain", &self.drain)
+            .field("replace_with", &self.replace_with)
+            .finish()
+    }
+}
+
+/// An extracting iterator for `IndexMap`.
+///
+/// This `struct` is created by [`IndexMap::extract_if()`].
+/// See its documentation for more.
+pub struct ExtractIf<'a, K, V, F> {
+    inner: ExtractCore<'a, K, V>,
+    pred: F,
+}
+
+impl<K, V, F> ExtractIf<'_, K, V, F> {
+    #[track_caller]
+    pub(super) fn new<R>(core: &mut Core<K, V>, range: R, pred: F) -> ExtractIf<'_, K, V, F>
+    where
+        R: RangeBounds<usize>,
+        F: FnMut(&K, &mut V) -> bool,
+    {
+        ExtractIf {
+            inner: core.extract(range),
+            pred,
+        }
+    }
+}
+
+impl<K, V, F> Iterator for ExtractIf<'_, K, V, F>
+where
+    F: FnMut(&K, &mut V) -> bool,
+{
+    type Item = (K, V);
+
+    fn next(&mut self) -> Option<Self::Item> {
+        self.inner
+            .extract_if(|bucket| {
+                let (key, value) = bucket.ref_mut();
+                (self.pred)(key, value)
+            })
+            .map(Bucket::key_value)
+    }
+
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        (0, Some(self.inner.remaining()))
+    }
+}
+
+impl<K, V, F> FusedIterator for ExtractIf<'_, K, V, F> where F: FnMut(&K, &mut V) -> bool {}
+
+impl<K, V, F> fmt::Debug for ExtractIf<'_, K, V, F>
+where
+    K: fmt::Debug,
+    V: fmt::Debug,
+{
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("ExtractIf").finish_non_exhaustive()
+    }
+}

vendor/indexmap/src/map/mutable.rs

@@ -0,0 +1,165 @@
+use core::hash::{BuildHasher, Hash};
+
+use super::{
+    Bucket, Entry, Equivalent, IndexMap, IndexedEntry, IterMut2, OccupiedEntry, VacantEntry,
+};
+
+/// Opt-in mutable access to [`IndexMap`] keys.
+///
+/// These methods expose `&mut K`, mutable references to the key as it is stored
+/// in the map.
+/// You are allowed to modify the keys in the map **if the modification
+/// does not change the key's hash and equality**.
+///
+/// If keys are modified erroneously, you can no longer look them up.
+/// This is sound (memory safe) but a logical error hazard (just like
+/// implementing `PartialEq`, `Eq`, or `Hash` incorrectly would be).
+///
+/// `use` this trait to enable its methods for `IndexMap`.
+///
+/// This trait is sealed and cannot be implemented for types outside this crate.
+#[expect(private_bounds)]
+pub trait MutableKeys: Sealed {
+    type Key;
+    type Value;
+
+    /// Return item index, mutable reference to key and value
+    ///
+    /// Computes in **O(1)** time (average).
+    fn get_full_mut2<Q>(&mut self, key: &Q) -> Option<(usize, &mut Self::Key, &mut Self::Value)>
+    where
+        Q: ?Sized + Hash + Equivalent<Self::Key>;
+
+    /// Return mutable reference to key and value at an index.
+    ///
+    /// Valid indices are `0 <= index < self.len()`.
+    ///
+    /// Computes in **O(1)** time.
+    fn get_index_mut2(&mut self, index: usize) -> Option<(&mut Self::Key, &mut Self::Value)>;
+
+    /// Return an iterator over the key-value pairs of the map, in their order
+    fn iter_mut2(&mut self) -> IterMut2<'_, Self::Key, Self::Value>;
+
+    /// Scan through each key-value pair in the map and keep those where the
+    /// closure `keep` returns `true`.
+    ///
+    /// The elements are visited in order, and remaining elements keep their
+    /// order.
+    ///
+    /// Computes in **O(n)** time (average).
+    fn retain2<F>(&mut self, keep: F)
+    where
+        F: FnMut(&mut Self::Key, &mut Self::Value) -> bool;
+}
+
+/// Opt-in mutable access to [`IndexMap`] keys.
+///
+/// See [`MutableKeys`] for more information.
+impl<K, V, S> MutableKeys for IndexMap<K, V, S>
+where
+    S: BuildHasher,
+{
+    type Key = K;
+    type Value = V;
+
+    fn get_full_mut2<Q>(&mut self, key: &Q) -> Option<(usize, &mut K, &mut V)>
+    where
+        Q: ?Sized + Hash + Equivalent<K>,
+    {
+        if let Some(i) = self.get_index_of(key) {
+            let entry = &mut self.as_entries_mut()[i];
+            Some((i, &mut entry.key, &mut entry.value))
+        } else {
+            None
+        }
+    }
+
+    fn get_index_mut2(&mut self, index: usize) -> Option<(&mut K, &mut V)> {
+        self.as_entries_mut().get_mut(index).map(Bucket::muts)
+    }
+
+    fn iter_mut2(&mut self) -> IterMut2<'_, Self::Key, Self::Value> {
+        IterMut2::new(self.as_entries_mut())
+    }
+
+    fn retain2<F>(&mut self, keep: F)
+    where
+        F: FnMut(&mut K, &mut V) -> bool,
+    {
+        self.core.retain_in_order(keep);
+    }
+}
+
+/// Opt-in mutable access to [`Entry`] keys.
+///
+/// These methods expose `&mut K`, mutable references to the key as it is stored
+/// in the map.
+/// You are allowed to modify the keys in the map **if the modification
+/// does not change the key's hash and equality**.
+///
+/// If keys are modified erroneously, you can no longer look them up.
+/// This is sound (memory safe) but a logical error hazard (just like
+/// implementing `PartialEq`, `Eq`, or `Hash` incorrectly would be).
+///
+/// `use` this trait to enable its methods for `Entry`.
+///
+/// This trait is sealed and cannot be implemented for types outside this crate.
+#[expect(private_bounds)]
+pub trait MutableEntryKey: Sealed {
+    type Key;
+
+    /// Gets a mutable reference to the entry's key, either within the map if occupied,
+    /// or else the new key that was used to find the entry.
+    fn key_mut(&mut self) -> &mut Self::Key;
+}
+
+/// Opt-in mutable access to [`Entry`] keys.
+///
+/// See [`MutableEntryKey`] for more information.
+impl<K, V> MutableEntryKey for Entry<'_, K, V> {
+    type Key = K;
+    fn key_mut(&mut self) -> &mut Self::Key {
+        match self {
+            Entry::Occupied(e) => e.key_mut(),
+            Entry::Vacant(e) => e.key_mut(),
+        }
+    }
+}
+
+/// Opt-in mutable access to [`OccupiedEntry`] keys.
+///
+/// See [`MutableEntryKey`] for more information.
+impl<K, V> MutableEntryKey for OccupiedEntry<'_, K, V> {
+    type Key = K;
+    fn key_mut(&mut self) -> &mut Self::Key {
+        &mut self.get_bucket_mut().key
+    }
+}
+
+/// Opt-in mutable access to [`VacantEntry`] keys.
+///
+/// See [`MutableEntryKey`] for more information.
+impl<K, V> MutableEntryKey for VacantEntry<'_, K, V> {
+    type Key = K;
+    fn key_mut(&mut self) -> &mut Self::Key {
+        self.key_mut()
+    }
+}
+
+/// Opt-in mutable access to [`IndexedEntry`] keys.
+///
+/// See [`MutableEntryKey`] for more information.
+impl<K, V> MutableEntryKey for IndexedEntry<'_, K, V> {
+    type Key = K;
+    fn key_mut(&mut self) -> &mut Self::Key {
+        self.key_mut()
+    }
+}
+
+trait Sealed {}
+
+impl<K, V, S> Sealed for IndexMap<K, V, S> {}
+impl<K, V> Sealed for Entry<'_, K, V> {}
+impl<K, V> Sealed for OccupiedEntry<'_, K, V> {}
+impl<K, V> Sealed for VacantEntry<'_, K, V> {}
+impl<K, V> Sealed for IndexedEntry<'_, K, V> {}

vendor/indexmap/src/map/raw_entry_v1.rs

@@ -0,0 +1,636 @@
+//! Opt-in access to the experimental raw entry API.
+//!
+//! This module is designed to mimic the raw entry API of [`HashMap`][std::collections::hash_map],
+//! matching its unstable state as of Rust 1.75. See the tracking issue
+//! [rust#56167](https://github.com/rust-lang/rust/issues/56167) for more details.
+//!
+//! The trait [`RawEntryApiV1`] and the `_v1` suffix on its methods are meant to insulate this for
+//! the future, in case later breaking changes are needed. If the standard library stabilizes its
+//! `hash_raw_entry` feature (or some replacement), matching *inherent* methods will be added to
+//! `IndexMap` without such an opt-in trait.
+
+use super::{Core, OccupiedEntry};
+use crate::{Equivalent, HashValue, IndexMap};
+use core::fmt;
+use core::hash::{BuildHasher, Hash};
+use core::marker::PhantomData;
+use core::mem;
+
+/// Opt-in access to the experimental raw entry API.
+///
+/// See the [`raw_entry_v1`][self] module documentation for more information.
+#[expect(private_bounds)]
+pub trait RawEntryApiV1<K, V, S>: Sealed {
+    /// Creates a raw immutable entry builder for the [`IndexMap`].
+    ///
+    /// Raw entries provide the lowest level of control for searching and
+    /// manipulating a map. They must be manually initialized with a hash and
+    /// then manually searched.
+    ///
+    /// This is useful for
+    /// * Hash memoization
+    /// * Using a search key that doesn't work with the [`Equivalent`] trait
+    /// * Using custom comparison logic without newtype wrappers
+    ///
+    /// Unless you are in such a situation, higher-level and more foolproof APIs like
+    /// [`get`][IndexMap::get] should be preferred.
+    ///
+    /// Immutable raw entries have very limited use; you might instead want
+    /// [`raw_entry_mut_v1`][Self::raw_entry_mut_v1].
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use core::hash::BuildHasher;
+    /// use indexmap::map::{IndexMap, RawEntryApiV1};
+    ///
+    /// let mut map = IndexMap::new();
+    /// map.extend([("a", 100), ("b", 200), ("c", 300)]);
+    ///
+    /// for k in ["a", "b", "c", "d", "e", "f"] {
+    ///     let hash = map.hasher().hash_one(k);
+    ///     let i = map.get_index_of(k);
+    ///     let v = map.get(k);
+    ///     let kv = map.get_key_value(k);
+    ///     let ikv = map.get_full(k);
+    ///
+    ///     println!("Key: {} and value: {:?}", k, v);
+    ///
+    ///     assert_eq!(map.raw_entry_v1().from_key(k), kv);
+    ///     assert_eq!(map.raw_entry_v1().from_hash(hash, |q| *q == k), kv);
+    ///     assert_eq!(map.raw_entry_v1().from_key_hashed_nocheck(hash, k), kv);
+    ///     assert_eq!(map.raw_entry_v1().from_hash_full(hash, |q| *q == k), ikv);
+    ///     assert_eq!(map.raw_entry_v1().index_from_hash(hash, |q| *q == k), i);
+    /// }
+    /// ```
+    fn raw_entry_v1(&self) -> RawEntryBuilder<'_, K, V, S>;
+
+    /// Creates a raw entry builder for the [`IndexMap`].
+    ///
+    /// Raw entries provide the lowest level of control for searching and
+    /// manipulating a map. They must be manually initialized with a hash and
+    /// then manually searched. After this, insertions into a vacant entry
+    /// still require an owned key to be provided.
+    ///
+    /// Raw entries are useful for such exotic situations as:
+    ///
+    /// * Hash memoization
+    /// * Deferring the creation of an owned key until it is known to be required
+    /// * Using a search key that doesn't work with the [`Equivalent`] trait
+    /// * Using custom comparison logic without newtype wrappers
+    ///
+    /// Because raw entries provide much more low-level control, it's much easier
+    /// to put the `IndexMap` into an inconsistent state which, while memory-safe,
+    /// will cause the map to produce seemingly random results. Higher-level and more
+    /// foolproof APIs like [`entry`][IndexMap::entry] should be preferred when possible.
+    ///
+    /// Raw entries give mutable access to the keys. This must not be used
+    /// to modify how the key would compare or hash, as the map will not re-evaluate
+    /// where the key should go, meaning the keys may become "lost" if their
+    /// location does not reflect their state. For instance, if you change a key
+    /// so that the map now contains keys which compare equal, search may start
+    /// acting erratically, with two keys randomly masking each other. Implementations
+    /// are free to assume this doesn't happen (within the limits of memory-safety).
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use core::hash::BuildHasher;
+    /// use indexmap::map::{IndexMap, RawEntryApiV1};
+    /// use indexmap::map::raw_entry_v1::RawEntryMut;
+    ///
+    /// let mut map = IndexMap::new();
+    /// map.extend([("a", 100), ("b", 200), ("c", 300)]);
+    ///
+    /// // Existing key (insert and update)
+    /// match map.raw_entry_mut_v1().from_key("a") {
+    ///     RawEntryMut::Vacant(_) => unreachable!(),
+    ///     RawEntryMut::Occupied(mut view) => {
+    ///         assert_eq!(view.index(), 0);
+    ///         assert_eq!(view.get(), &100);
+    ///         let v = view.get_mut();
+    ///         let new_v = (*v) * 10;
+    ///         *v = new_v;
+    ///         assert_eq!(view.insert(1111), 1000);
+    ///     }
+    /// }
+    ///
+    /// assert_eq!(map["a"], 1111);
+    /// assert_eq!(map.len(), 3);
+    ///
+    /// // Existing key (take)
+    /// let hash = map.hasher().hash_one("c");
+    /// match map.raw_entry_mut_v1().from_key_hashed_nocheck(hash, "c") {
+    ///     RawEntryMut::Vacant(_) => unreachable!(),
+    ///     RawEntryMut::Occupied(view) => {
+    ///         assert_eq!(view.index(), 2);
+    ///         assert_eq!(view.shift_remove_entry(), ("c", 300));
+    ///     }
+    /// }
+    /// assert_eq!(map.raw_entry_v1().from_key("c"), None);
+    /// assert_eq!(map.len(), 2);
+    ///
+    /// // Nonexistent key (insert and update)
+    /// let key = "d";
+    /// let hash = map.hasher().hash_one(key);
+    /// match map.raw_entry_mut_v1().from_hash(hash, |q| *q == key) {
+    ///     RawEntryMut::Occupied(_) => unreachable!(),
+    ///     RawEntryMut::Vacant(view) => {
+    ///         assert_eq!(view.index(), 2);
+    ///         let (k, value) = view.insert("d", 4000);
+    ///         assert_eq!((*k, *value), ("d", 4000));
+    ///         *value = 40000;
+    ///     }
+    /// }
+    /// assert_eq!(map["d"], 40000);
+    /// assert_eq!(map.len(), 3);
+    ///
+    /// match map.raw_entry_mut_v1().from_hash(hash, |q| *q == key) {
+    ///     RawEntryMut::Vacant(_) => unreachable!(),
+    ///     RawEntryMut::Occupied(view) => {
+    ///         assert_eq!(view.index(), 2);
+    ///         assert_eq!(view.swap_remove_entry(), ("d", 40000));
+    ///     }
+    /// }
+    /// assert_eq!(map.get("d"), None);
+    /// assert_eq!(map.len(), 2);
+    /// ```
+    fn raw_entry_mut_v1(&mut self) -> RawEntryBuilderMut<'_, K, V, S>;
+}
+
+impl<K, V, S> RawEntryApiV1<K, V, S> for IndexMap<K, V, S> {
+    fn raw_entry_v1(&self) -> RawEntryBuilder<'_, K, V, S> {
+        RawEntryBuilder { map: self }
+    }
+
+    fn raw_entry_mut_v1(&mut self) -> RawEntryBuilderMut<'_, K, V, S> {
+        RawEntryBuilderMut { map: self }
+    }
+}
+
+/// A builder for computing where in an [`IndexMap`] a key-value pair would be stored.
+///
+/// This `struct` is created by the [`IndexMap::raw_entry_v1`] method, provided by the
+/// [`RawEntryApiV1`] trait. See its documentation for more.
+pub struct RawEntryBuilder<'a, K, V, S> {
+    map: &'a IndexMap<K, V, S>,
+}
+
+impl<K, V, S> fmt::Debug for RawEntryBuilder<'_, K, V, S> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("RawEntryBuilder").finish_non_exhaustive()
+    }
+}
+
+impl<'a, K, V, S> RawEntryBuilder<'a, K, V, S> {
+    /// Access an entry by key.
+    pub fn from_key<Q>(self, key: &Q) -> Option<(&'a K, &'a V)>
+    where
+        S: BuildHasher,
+        Q: ?Sized + Hash + Equivalent<K>,
+    {
+        self.map.get_key_value(key)
+    }
+
+    /// Access an entry by a key and its hash.
+    pub fn from_key_hashed_nocheck<Q>(self, hash: u64, key: &Q) -> Option<(&'a K, &'a V)>
+    where
+        Q: ?Sized + Equivalent<K>,
+    {
+        let hash = HashValue(hash as usize);
+        let i = self.map.core.get_index_of(hash, key)?;
+        self.map.get_index(i)
+    }
+
+    /// Access an entry by hash.
+    pub fn from_hash<F>(self, hash: u64, is_match: F) -> Option<(&'a K, &'a V)>
+    where
+        F: FnMut(&K) -> bool,
+    {
+        let map = self.map;
+        let i = self.index_from_hash(hash, is_match)?;
+        map.get_index(i)
+    }
+
+    /// Access an entry by hash, including its index.
+    pub fn from_hash_full<F>(self, hash: u64, is_match: F) -> Option<(usize, &'a K, &'a V)>
+    where
+        F: FnMut(&K) -> bool,
+    {
+        let map = self.map;
+        let i = self.index_from_hash(hash, is_match)?;
+        let (key, value) = map.get_index(i)?;
+        Some((i, key, value))
+    }
+
+    /// Access the index of an entry by hash.
+    pub fn index_from_hash<F>(self, hash: u64, is_match: F) -> Option<usize>
+    where
+        F: FnMut(&K) -> bool,
+    {
+        let hash = HashValue(hash as usize);
+        self.map.core.get_index_of_raw(hash, is_match)
+    }
+}
+
+/// A builder for computing where in an [`IndexMap`] a key-value pair would be stored.
+///
+/// This `struct` is created by the [`IndexMap::raw_entry_mut_v1`] method, provided by the
+/// [`RawEntryApiV1`] trait. See its documentation for more.
+pub struct RawEntryBuilderMut<'a, K, V, S> {
+    map: &'a mut IndexMap<K, V, S>,
+}
+
+impl<K, V, S> fmt::Debug for RawEntryBuilderMut<'_, K, V, S> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("RawEntryBuilderMut").finish_non_exhaustive()
+    }
+}
+
+impl<'a, K, V, S> RawEntryBuilderMut<'a, K, V, S> {
+    /// Access an entry by key.
+    pub fn from_key<Q>(self, key: &Q) -> RawEntryMut<'a, K, V, S>
+    where
+        S: BuildHasher,
+        Q: ?Sized + Hash + Equivalent<K>,
+    {
+        let hash = self.map.hash(key);
+        self.from_key_hashed_nocheck(hash.get(), key)
+    }
+
+    /// Access an entry by a key and its hash.
+    pub fn from_key_hashed_nocheck<Q>(self, hash: u64, key: &Q) -> RawEntryMut<'a, K, V, S>
+    where
+        Q: ?Sized + Equivalent<K>,
+    {
+        self.from_hash(hash, |k| Q::equivalent(key, k))
+    }
+
+    /// Access an entry by hash.
+    pub fn from_hash<F>(self, hash: u64, is_match: F) -> RawEntryMut<'a, K, V, S>
+    where
+        F: FnMut(&K) -> bool,
+    {
+        let hash = HashValue(hash as usize);
+        match OccupiedEntry::from_hash(&mut self.map.core, hash, is_match) {
+            Ok(inner) => RawEntryMut::Occupied(RawOccupiedEntryMut {
+                inner,
+                hash_builder: PhantomData,
+            }),
+            Err(map) => RawEntryMut::Vacant(RawVacantEntryMut {
+                map,
+                hash_builder: &self.map.hash_builder,
+            }),
+        }
+    }
+}
+
+/// Raw entry for an existing key-value pair or a vacant location to
+/// insert one.
+pub enum RawEntryMut<'a, K, V, S> {
+    /// Existing slot with equivalent key.
+    Occupied(RawOccupiedEntryMut<'a, K, V, S>),
+    /// Vacant slot (no equivalent key in the map).
+    Vacant(RawVacantEntryMut<'a, K, V, S>),
+}
+
+impl<K: fmt::Debug, V: fmt::Debug, S> fmt::Debug for RawEntryMut<'_, K, V, S> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let mut tuple = f.debug_tuple("RawEntryMut");
+        match self {
+            Self::Vacant(v) => tuple.field(v),
+            Self::Occupied(o) => tuple.field(o),
+        };
+        tuple.finish()
+    }
+}
+
+impl<'a, K, V, S> RawEntryMut<'a, K, V, S> {
+    /// Return the index where the key-value pair exists or may be inserted.
+    #[inline]
+    pub fn index(&self) -> usize {
+        match self {
+            Self::Occupied(entry) => entry.index(),
+            Self::Vacant(entry) => entry.index(),
+        }
+    }
+
+    /// Inserts the given default key and value in the entry if it is vacant and returns mutable
+    /// references to them. Otherwise mutable references to an already existent pair are returned.
+    pub fn or_insert(self, default_key: K, default_value: V) -> (&'a mut K, &'a mut V)
+    where
+        K: Hash,
+        S: BuildHasher,
+    {
+        match self {
+            Self::Occupied(entry) => entry.into_key_value_mut(),
+            Self::Vacant(entry) => entry.insert(default_key, default_value),
+        }
+    }
+
+    /// Inserts the result of the `call` function in the entry if it is vacant and returns mutable
+    /// references to them. Otherwise mutable references to an already existent pair are returned.
+    pub fn or_insert_with<F>(self, call: F) -> (&'a mut K, &'a mut V)
+    where
+        F: FnOnce() -> (K, V),
+        K: Hash,
+        S: BuildHasher,
+    {
+        match self {
+            Self::Occupied(entry) => entry.into_key_value_mut(),
+            Self::Vacant(entry) => {
+                let (key, value) = call();
+                entry.insert(key, value)
+            }
+        }
+    }
+
+    /// Modifies the entry if it is occupied.
+    pub fn and_modify<F>(mut self, f: F) -> Self
+    where
+        F: FnOnce(&mut K, &mut V),
+    {
+        if let Self::Occupied(entry) = &mut self {
+            let (k, v) = entry.get_key_value_mut();
+            f(k, v);
+        }
+        self
+    }
+}
+
+/// A raw view into an occupied entry in an [`IndexMap`].
+/// It is part of the [`RawEntryMut`] enum.
+pub struct RawOccupiedEntryMut<'a, K, V, S> {
+    inner: OccupiedEntry<'a, K, V>,
+    hash_builder: PhantomData<&'a S>,
+}
+
+impl<K: fmt::Debug, V: fmt::Debug, S> fmt::Debug for RawOccupiedEntryMut<'_, K, V, S> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("RawOccupiedEntryMut")
+            .field("key", self.key())
+            .field("value", self.get())
+            .finish_non_exhaustive()
+    }
+}
+
+impl<'a, K, V, S> RawOccupiedEntryMut<'a, K, V, S> {
+    /// Return the index of the key-value pair
+    #[inline]
+    pub fn index(&self) -> usize {
+        self.inner.index()
+    }
+
+    /// Gets a reference to the entry's key in the map.
+    ///
+    /// Note that this is not the key that was used to find the entry. There may be an observable
+    /// difference if the key type has any distinguishing features outside of `Hash` and `Eq`, like
+    /// extra fields or the memory address of an allocation.
+    pub fn key(&self) -> &K {
+        self.inner.key()
+    }
+
+    /// Gets a mutable reference to the entry's key in the map.
+    ///
+    /// Note that this is not the key that was used to find the entry. There may be an observable
+    /// difference if the key type has any distinguishing features outside of `Hash` and `Eq`, like
+    /// extra fields or the memory address of an allocation.
+    pub fn key_mut(&mut self) -> &mut K {
+        &mut self.inner.get_bucket_mut().key
+    }
+
+    /// Converts into a mutable reference to the entry's key in the map,
+    /// with a lifetime bound to the map itself.
+    ///
+    /// Note that this is not the key that was used to find the entry. There may be an observable
+    /// difference if the key type has any distinguishing features outside of `Hash` and `Eq`, like
+    /// extra fields or the memory address of an allocation.
+    pub fn into_key(self) -> &'a mut K {
+        &mut self.inner.into_bucket().key
+    }
+
+    /// Gets a reference to the entry's value in the map.
+    pub fn get(&self) -> &V {
+        self.inner.get()
+    }
+
+    /// Gets a mutable reference to the entry's value in the map.
+    ///
+    /// If you need a reference which may outlive the destruction of the
+    /// [`RawEntryMut`] value, see [`into_mut`][Self::into_mut].
+    pub fn get_mut(&mut self) -> &mut V {
+        self.inner.get_mut()
+    }
+
+    /// Converts into a mutable reference to the entry's value in the map,
+    /// with a lifetime bound to the map itself.
+    pub fn into_mut(self) -> &'a mut V {
+        self.inner.into_mut()
+    }
+
+    /// Gets a reference to the entry's key and value in the map.
+    pub fn get_key_value(&self) -> (&K, &V) {
+        self.inner.get_bucket().refs()
+    }
+
+    /// Gets a reference to the entry's key and value in the map.
+    pub fn get_key_value_mut(&mut self) -> (&mut K, &mut V) {
+        self.inner.get_bucket_mut().muts()
+    }
+
+    /// Converts into a mutable reference to the entry's key and value in the map,
+    /// with a lifetime bound to the map itself.
+    pub fn into_key_value_mut(self) -> (&'a mut K, &'a mut V) {
+        self.inner.into_bucket().muts()
+    }
+
+    /// Sets the value of the entry, and returns the entry's old value.
+    pub fn insert(&mut self, value: V) -> V {
+        self.inner.insert(value)
+    }
+
+    /// Sets the key of the entry, and returns the entry's old key.
+    pub fn insert_key(&mut self, key: K) -> K {
+        mem::replace(self.key_mut(), key)
+    }
+
+    /// Remove the key, value pair stored in the map for this entry, and return the value.
+    ///
+    /// **NOTE:** This is equivalent to [`.swap_remove()`][Self::swap_remove], replacing this
+    /// entry's position with the last element, and it is deprecated in favor of calling that
+    /// explicitly. If you need to preserve the relative order of the keys in the map, use
+    /// [`.shift_remove()`][Self::shift_remove] instead.
+    #[deprecated(note = "`remove` disrupts the map order -- \
+        use `swap_remove` or `shift_remove` for explicit behavior.")]
+    pub fn remove(self) -> V {
+        self.swap_remove()
+    }
+
+    /// Remove the key, value pair stored in the map for this entry, and return the value.
+    ///
+    /// Like [`Vec::swap_remove`][alloc::vec::Vec::swap_remove], the pair is removed by swapping it
+    /// with the last element of the map and popping it off.
+    /// **This perturbs the position of what used to be the last element!**
+    ///
+    /// Computes in **O(1)** time (average).
+    pub fn swap_remove(self) -> V {
+        self.inner.swap_remove()
+    }
+
+    /// Remove the key, value pair stored in the map for this entry, and return the value.
+    ///
+    /// Like [`Vec::remove`][alloc::vec::Vec::remove], the pair is removed by shifting all of the
+    /// elements that follow it, preserving their relative order.
+    /// **This perturbs the index of all of those elements!**
+    ///
+    /// Computes in **O(n)** time (average).
+    pub fn shift_remove(self) -> V {
+        self.inner.shift_remove()
+    }
+
+    /// Remove and return the key, value pair stored in the map for this entry
+    ///
+    /// **NOTE:** This is equivalent to [`.swap_remove_entry()`][Self::swap_remove_entry],
+    /// replacing this entry's position with the last element, and it is deprecated in favor of
+    /// calling that explicitly. If you need to preserve the relative order of the keys in the map,
+    /// use [`.shift_remove_entry()`][Self::shift_remove_entry] instead.
+    #[deprecated(note = "`remove_entry` disrupts the map order -- \
+        use `swap_remove_entry` or `shift_remove_entry` for explicit behavior.")]
+    pub fn remove_entry(self) -> (K, V) {
+        self.swap_remove_entry()
+    }
+
+    /// Remove and return the key, value pair stored in the map for this entry
+    ///
+    /// Like [`Vec::swap_remove`][alloc::vec::Vec::swap_remove], the pair is removed by swapping it
+    /// with the last element of the map and popping it off.
+    /// **This perturbs the position of what used to be the last element!**
+    ///
+    /// Computes in **O(1)** time (average).
+    pub fn swap_remove_entry(self) -> (K, V) {
+        self.inner.swap_remove_entry()
+    }
+
+    /// Remove and return the key, value pair stored in the map for this entry
+    ///
+    /// Like [`Vec::remove`][alloc::vec::Vec::remove], the pair is removed by shifting all of the
+    /// elements that follow it, preserving their relative order.
+    /// **This perturbs the index of all of those elements!**
+    ///
+    /// Computes in **O(n)** time (average).
+    pub fn shift_remove_entry(self) -> (K, V) {
+        self.inner.shift_remove_entry()
+    }
+
+    /// Moves the position of the entry to a new index
+    /// by shifting all other entries in-between.
+    ///
+    /// This is equivalent to [`IndexMap::move_index`]
+    /// coming `from` the current [`.index()`][Self::index].
+    ///
+    /// * If `self.index() < to`, the other pairs will shift down while the targeted pair moves up.
+    /// * If `self.index() > to`, the other pairs will shift up while the targeted pair moves down.
+    ///
+    /// ***Panics*** if `to` is out of bounds.
+    ///
+    /// Computes in **O(n)** time (average).
+    #[track_caller]
+    pub fn move_index(self, to: usize) {
+        self.inner.move_index(to);
+    }
+
+    /// Swaps the position of entry with another.
+    ///
+    /// This is equivalent to [`IndexMap::swap_indices`]
+    /// with the current [`.index()`][Self::index] as one of the two being swapped.
+    ///
+    /// ***Panics*** if the `other` index is out of bounds.
+    ///
+    /// Computes in **O(1)** time (average).
+    #[track_caller]
+    pub fn swap_indices(self, other: usize) {
+        self.inner.swap_indices(other);
+    }
+}
+
+/// A view into a vacant raw entry in an [`IndexMap`].
+/// It is part of the [`RawEntryMut`] enum.
+pub struct RawVacantEntryMut<'a, K, V, S> {
+    map: &'a mut Core<K, V>,
+    hash_builder: &'a S,
+}
+
+impl<K, V, S> fmt::Debug for RawVacantEntryMut<'_, K, V, S> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("RawVacantEntryMut").finish_non_exhaustive()
+    }
+}
+
+impl<'a, K, V, S> RawVacantEntryMut<'a, K, V, S> {
+    /// Return the index where a key-value pair may be inserted.
+    pub fn index(&self) -> usize {
+        self.map.len()
+    }
+
+    /// Inserts the given key and value into the map,
+    /// and returns mutable references to them.
+    pub fn insert(self, key: K, value: V) -> (&'a mut K, &'a mut V)
+    where
+        K: Hash,
+        S: BuildHasher,
+    {
+        let h = self.hash_builder.hash_one(&key);
+        self.insert_hashed_nocheck(h, key, value)
+    }
+
+    /// Inserts the given key and value into the map with the provided hash,
+    /// and returns mutable references to them.
+    pub fn insert_hashed_nocheck(self, hash: u64, key: K, value: V) -> (&'a mut K, &'a mut V) {
+        let hash = HashValue(hash as usize);
+        self.map.insert_unique(hash, key, value).muts()
+    }
+
+    /// Inserts the given key and value into the map at the given index,
+    /// shifting others to the right, and returns mutable references to them.
+    ///
+    /// ***Panics*** if `index` is out of bounds.
+    ///
+    /// Computes in **O(n)** time (average).
+    #[track_caller]
+    pub fn shift_insert(self, index: usize, key: K, value: V) -> (&'a mut K, &'a mut V)
+    where
+        K: Hash,
+        S: BuildHasher,
+    {
+        let h = self.hash_builder.hash_one(&key);
+        self.shift_insert_hashed_nocheck(index, h, key, value)
+    }
+
+    /// Inserts the given key and value into the map with the provided hash
+    /// at the given index, and returns mutable references to them.
+    ///
+    /// ***Panics*** if `index` is out of bounds.
+    ///
+    /// Computes in **O(n)** time (average).
+    #[track_caller]
+    pub fn shift_insert_hashed_nocheck(
+        self,
+        index: usize,
+        hash: u64,
+        key: K,
+        value: V,
+    ) -> (&'a mut K, &'a mut V) {
+        let hash = HashValue(hash as usize);
+        self.map.shift_insert_unique(index, hash, key, value).muts()
+    }
+}
+
+trait Sealed {}
+
+impl<K, V, S> Sealed for IndexMap<K, V, S> {}
+
+#[test]
+fn assert_send_sync() {
+    fn assert_send_sync<T: Send + Sync>() {}
+    assert_send_sync::<RawEntryMut<'_, i32, i32, ()>>();
+}

vendor/indexmap/src/map/serde_seq.rs

@@ -0,0 +1,138 @@
+//! Functions to serialize and deserialize an [`IndexMap`] as an ordered sequence.
+//!
+//! The default `serde` implementation serializes `IndexMap` as a normal map,
+//! but there is no guarantee that serialization formats will preserve the order
+//! of the key-value pairs. This module serializes `IndexMap` as a sequence of
+//! `(key, value)` elements instead, in order.
+//!
+//! This module may be used in a field attribute for derived implementations:
+//!
+//! ```
+//! # use indexmap::IndexMap;
+//! # use serde::{Deserialize, Serialize};
+//! #[derive(Deserialize, Serialize)]
+//! struct Data {
+//!     #[serde(with = "indexmap::map::serde_seq")]
+//!     map: IndexMap<i32, u64>,
+//!     // ...
+//! }
+//! ```
+
+use serde_core::de::{Deserialize, Deserializer, SeqAccess, Visitor};
+use serde_core::ser::{Serialize, Serializer};
+
+use core::fmt::{self, Formatter};
+use core::hash::{BuildHasher, Hash};
+use core::marker::PhantomData;
+
+use crate::map::Slice as MapSlice;
+use crate::serde::cautious_capacity;
+use crate::set::Slice as SetSlice;
+use crate::IndexMap;
+
+/// Serializes a [`map::Slice`][MapSlice] as an ordered sequence.
+///
+/// This behaves like [`crate::map::serde_seq`] for `IndexMap`, serializing a sequence
+/// of `(key, value)` pairs, rather than as a map that might not preserve order.
+impl<K, V> Serialize for MapSlice<K, V>
+where
+    K: Serialize,
+    V: Serialize,
+{
+    fn serialize<T>(&self, serializer: T) -> Result<T::Ok, T::Error>
+    where
+        T: Serializer,
+    {
+        serializer.collect_seq(self)
+    }
+}
+
+/// Serializes a [`set::Slice`][SetSlice] as an ordered sequence.
+impl<T> Serialize for SetSlice<T>
+where
+    T: Serialize,
+{
+    fn serialize<Se>(&self, serializer: Se) -> Result<Se::Ok, Se::Error>
+    where
+        Se: Serializer,
+    {
+        serializer.collect_seq(self)
+    }
+}
+
+/// Serializes an [`IndexMap`] as an ordered sequence.
+///
+/// This function may be used in a field attribute for deriving [`Serialize`]:
+///
+/// ```
+/// # use indexmap::IndexMap;
+/// # use serde::Serialize;
+/// #[derive(Serialize)]
+/// struct Data {
+///     #[serde(serialize_with = "indexmap::map::serde_seq::serialize")]
+///     map: IndexMap<i32, u64>,
+///     // ...
+/// }
+/// ```
+pub fn serialize<K, V, S, T>(map: &IndexMap<K, V, S>, serializer: T) -> Result<T::Ok, T::Error>
+where
+    K: Serialize,
+    V: Serialize,
+    T: Serializer,
+{
+    serializer.collect_seq(map)
+}
+
+/// Visitor to deserialize a *sequenced* `IndexMap`
+struct SeqVisitor<K, V, S>(PhantomData<(K, V, S)>);
+
+impl<'de, K, V, S> Visitor<'de> for SeqVisitor<K, V, S>
+where
+    K: Deserialize<'de> + Eq + Hash,
+    V: Deserialize<'de>,
+    S: Default + BuildHasher,
+{
+    type Value = IndexMap<K, V, S>;
+
+    fn expecting(&self, formatter: &mut Formatter<'_>) -> fmt::Result {
+        write!(formatter, "a sequenced map")
+    }
+
+    fn visit_seq<A>(self, mut seq: A) -> Result<Self::Value, A::Error>
+    where
+        A: SeqAccess<'de>,
+    {
+        let capacity = cautious_capacity::<K, V>(seq.size_hint());
+        let mut map = IndexMap::with_capacity_and_hasher(capacity, S::default());
+
+        while let Some((key, value)) = seq.next_element()? {
+            map.insert(key, value);
+        }
+
+        Ok(map)
+    }
+}
+
+/// Deserializes an [`IndexMap`] from an ordered sequence.
+///
+/// This function may be used in a field attribute for deriving [`Deserialize`]:
+///
+/// ```
+/// # use indexmap::IndexMap;
+/// # use serde::Deserialize;
+/// #[derive(Deserialize)]
+/// struct Data {
+///     #[serde(deserialize_with = "indexmap::map::serde_seq::deserialize")]
+///     map: IndexMap<i32, u64>,
+///     // ...
+/// }
+/// ```
+pub fn deserialize<'de, D, K, V, S>(deserializer: D) -> Result<IndexMap<K, V, S>, D::Error>
+where
+    D: Deserializer<'de>,
+    K: Deserialize<'de> + Eq + Hash,
+    V: Deserialize<'de>,
+    S: Default + BuildHasher,
+{
+    deserializer.deserialize_seq(SeqVisitor(PhantomData))
+}

vendor/indexmap/src/map/slice.rs

@@ -0,0 +1,799 @@
+use super::{
+    Bucket, IndexMap, IntoIter, IntoKeys, IntoValues, Iter, IterMut, Keys, Values, ValuesMut,
+};
+use crate::util::{slice_eq, try_simplify_range};
+use crate::GetDisjointMutError;
+
+use alloc::boxed::Box;
+use alloc::vec::Vec;
+use core::cmp::Ordering;
+use core::fmt;
+use core::hash::{Hash, Hasher};
+use core::ops::{self, Bound, Index, IndexMut, RangeBounds};
+
+/// A dynamically-sized slice of key-value pairs in an [`IndexMap`].
+///
+/// This supports indexed operations much like a `[(K, V)]` slice,
+/// but not any hashed operations on the map keys.
+///
+/// Unlike `IndexMap`, `Slice` does consider the order for [`PartialEq`]
+/// and [`Eq`], and it also implements [`PartialOrd`], [`Ord`], and [`Hash`].
+#[repr(transparent)]
+pub struct Slice<K, V> {
+    pub(crate) entries: [Bucket<K, V>],
+}
+
+// SAFETY: `Slice<K, V>` is a transparent wrapper around `[Bucket<K, V>]`,
+// and reference lifetimes are bound together in function signatures.
+#[allow(unsafe_code)]
+impl<K, V> Slice<K, V> {
+    pub(crate) const fn from_slice(entries: &[Bucket<K, V>]) -> &Self {
+        unsafe { &*(entries as *const [Bucket<K, V>] as *const Self) }
+    }
+
+    pub(super) fn from_mut_slice(entries: &mut [Bucket<K, V>]) -> &mut Self {
+        unsafe { &mut *(entries as *mut [Bucket<K, V>] as *mut Self) }
+    }
+
+    pub(super) fn from_boxed(entries: Box<[Bucket<K, V>]>) -> Box<Self> {
+        unsafe { Box::from_raw(Box::into_raw(entries) as *mut Self) }
+    }
+
+    fn into_boxed(self: Box<Self>) -> Box<[Bucket<K, V>]> {
+        unsafe { Box::from_raw(Box::into_raw(self) as *mut [Bucket<K, V>]) }
+    }
+}
+
+impl<K, V> Slice<K, V> {
+    pub(crate) fn into_entries(self: Box<Self>) -> Vec<Bucket<K, V>> {
+        self.into_boxed().into_vec()
+    }
+
+    /// Returns an empty slice.
+    pub const fn new<'a>() -> &'a Self {
+        Self::from_slice(&[])
+    }
+
+    /// Returns an empty mutable slice.
+    pub fn new_mut<'a>() -> &'a mut Self {
+        Self::from_mut_slice(&mut [])
+    }
+
+    /// Return the number of key-value pairs in the map slice.
+    #[inline]
+    pub const fn len(&self) -> usize {
+        self.entries.len()
+    }
+
+    /// Returns true if the map slice contains no elements.
+    #[inline]
+    pub const fn is_empty(&self) -> bool {
+        self.entries.is_empty()
+    }
+
+    /// Get a key-value pair by index.
+    ///
+    /// Valid indices are `0 <= index < self.len()`.
+    pub fn get_index(&self, index: usize) -> Option<(&K, &V)> {
+        self.entries.get(index).map(Bucket::refs)
+    }
+
+    /// Get a key-value pair by index, with mutable access to the value.
+    ///
+    /// Valid indices are `0 <= index < self.len()`.
+    pub fn get_index_mut(&mut self, index: usize) -> Option<(&K, &mut V)> {
+        self.entries.get_mut(index).map(Bucket::ref_mut)
+    }
+
+    /// Returns a slice of key-value pairs in the given range of indices.
+    ///
+    /// Valid indices are `0 <= index < self.len()`.
+    pub fn get_range<R: RangeBounds<usize>>(&self, range: R) -> Option<&Self> {
+        let range = try_simplify_range(range, self.entries.len())?;
+        self.entries.get(range).map(Slice::from_slice)
+    }
+
+    /// Returns a mutable slice of key-value pairs in the given range of indices.
+    ///
+    /// Valid indices are `0 <= index < self.len()`.
+    pub fn get_range_mut<R: RangeBounds<usize>>(&mut self, range: R) -> Option<&mut Self> {
+        let range = try_simplify_range(range, self.entries.len())?;
+        self.entries.get_mut(range).map(Slice::from_mut_slice)
+    }
+
+    /// Get the first key-value pair.
+    pub fn first(&self) -> Option<(&K, &V)> {
+        self.entries.first().map(Bucket::refs)
+    }
+
+    /// Get the first key-value pair, with mutable access to the value.
+    pub fn first_mut(&mut self) -> Option<(&K, &mut V)> {
+        self.entries.first_mut().map(Bucket::ref_mut)
+    }
+
+    /// Get the last key-value pair.
+    pub fn last(&self) -> Option<(&K, &V)> {
+        self.entries.last().map(Bucket::refs)
+    }
+
+    /// Get the last key-value pair, with mutable access to the value.
+    pub fn last_mut(&mut self) -> Option<(&K, &mut V)> {
+        self.entries.last_mut().map(Bucket::ref_mut)
+    }
+
+    /// Divides one slice into two at an index.
+    ///
+    /// ***Panics*** if `index > len`.
+    /// For a non-panicking alternative see [`split_at_checked`][Self::split_at_checked].
+    #[track_caller]
+    pub fn split_at(&self, index: usize) -> (&Self, &Self) {
+        let (first, second) = self.entries.split_at(index);
+        (Self::from_slice(first), Self::from_slice(second))
+    }
+
+    /// Divides one mutable slice into two at an index.
+    ///
+    /// ***Panics*** if `index > len`.
+    /// For a non-panicking alternative see [`split_at_mut_checked`][Self::split_at_mut_checked].
+    #[track_caller]
+    pub fn split_at_mut(&mut self, index: usize) -> (&mut Self, &mut Self) {
+        let (first, second) = self.entries.split_at_mut(index);
+        (Self::from_mut_slice(first), Self::from_mut_slice(second))
+    }
+
+    /// Divides one slice into two at an index.
+    ///
+    /// Returns `None` if `index > len`.
+    pub fn split_at_checked(&self, index: usize) -> Option<(&Self, &Self)> {
+        let (first, second) = self.entries.split_at_checked(index)?;
+        Some((Self::from_slice(first), Self::from_slice(second)))
+    }
+
+    /// Divides one mutable slice into two at an index.
+    ///
+    /// Returns `None` if `index > len`.
+    pub fn split_at_mut_checked(&mut self, index: usize) -> Option<(&mut Self, &mut Self)> {
+        let (first, second) = self.entries.split_at_mut_checked(index)?;
+        Some((Self::from_mut_slice(first), Self::from_mut_slice(second)))
+    }
+
+    /// Returns the first key-value pair and the rest of the slice,
+    /// or `None` if it is empty.
+    pub fn split_first(&self) -> Option<((&K, &V), &Self)> {
+        if let [first, rest @ ..] = &self.entries {
+            Some((first.refs(), Self::from_slice(rest)))
+        } else {
+            None
+        }
+    }
+
+    /// Returns the first key-value pair and the rest of the slice,
+    /// with mutable access to the value, or `None` if it is empty.
+    pub fn split_first_mut(&mut self) -> Option<((&K, &mut V), &mut Self)> {
+        if let [first, rest @ ..] = &mut self.entries {
+            Some((first.ref_mut(), Self::from_mut_slice(rest)))
+        } else {
+            None
+        }
+    }
+
+    /// Returns the last key-value pair and the rest of the slice,
+    /// or `None` if it is empty.
+    pub fn split_last(&self) -> Option<((&K, &V), &Self)> {
+        if let [rest @ .., last] = &self.entries {
+            Some((last.refs(), Self::from_slice(rest)))
+        } else {
+            None
+        }
+    }
+
+    /// Returns the last key-value pair and the rest of the slice,
+    /// with mutable access to the value, or `None` if it is empty.
+    pub fn split_last_mut(&mut self) -> Option<((&K, &mut V), &mut Self)> {
+        if let [rest @ .., last] = &mut self.entries {
+            Some((last.ref_mut(), Self::from_mut_slice(rest)))
+        } else {
+            None
+        }
+    }
+
+    /// Return an iterator over the key-value pairs of the map slice.
+    pub fn iter(&self) -> Iter<'_, K, V> {
+        Iter::new(&self.entries)
+    }
+
+    /// Return an iterator over the key-value pairs of the map slice.
+    pub fn iter_mut(&mut self) -> IterMut<'_, K, V> {
+        IterMut::new(&mut self.entries)
+    }
+
+    /// Return an iterator over the keys of the map slice.
+    pub fn keys(&self) -> Keys<'_, K, V> {
+        Keys::new(&self.entries)
+    }
+
+    /// Return an owning iterator over the keys of the map slice.
+    pub fn into_keys(self: Box<Self>) -> IntoKeys<K, V> {
+        IntoKeys::new(self.into_entries())
+    }
+
+    /// Return an iterator over the values of the map slice.
+    pub fn values(&self) -> Values<'_, K, V> {
+        Values::new(&self.entries)
+    }
+
+    /// Return an iterator over mutable references to the the values of the map slice.
+    pub fn values_mut(&mut self) -> ValuesMut<'_, K, V> {
+        ValuesMut::new(&mut self.entries)
+    }
+
+    /// Return an owning iterator over the values of the map slice.
+    pub fn into_values(self: Box<Self>) -> IntoValues<K, V> {
+        IntoValues::new(self.into_entries())
+    }
+
+    /// Search over a sorted map for a key.
+    ///
+    /// Returns the position where that key is present, or the position where it can be inserted to
+    /// maintain the sort. See [`slice::binary_search`] for more details.
+    ///
+    /// Computes in **O(log(n))** time, which is notably less scalable than looking the key up in
+    /// the map this is a slice from using [`IndexMap::get_index_of`], but this can also position
+    /// missing keys.
+    pub fn binary_search_keys(&self, x: &K) -> Result<usize, usize>
+    where
+        K: Ord,
+    {
+        self.binary_search_by(|p, _| p.cmp(x))
+    }
+
+    /// Search over a sorted map with a comparator function.
+    ///
+    /// Returns the position where that value is present, or the position where it can be inserted
+    /// to maintain the sort. See [`slice::binary_search_by`] for more details.
+    ///
+    /// Computes in **O(log(n))** time.
+    #[inline]
+    pub fn binary_search_by<'a, F>(&'a self, mut f: F) -> Result<usize, usize>
+    where
+        F: FnMut(&'a K, &'a V) -> Ordering,
+    {
+        self.entries.binary_search_by(move |a| f(&a.key, &a.value))
+    }
+
+    /// Search over a sorted map with an extraction function.
+    ///
+    /// Returns the position where that value is present, or the position where it can be inserted
+    /// to maintain the sort. See [`slice::binary_search_by_key`] for more details.
+    ///
+    /// Computes in **O(log(n))** time.
+    #[inline]
+    pub fn binary_search_by_key<'a, B, F>(&'a self, b: &B, mut f: F) -> Result<usize, usize>
+    where
+        F: FnMut(&'a K, &'a V) -> B,
+        B: Ord,
+    {
+        self.binary_search_by(|k, v| f(k, v).cmp(b))
+    }
+
+    /// Checks if the keys of this slice are sorted.
+    #[inline]
+    pub fn is_sorted(&self) -> bool
+    where
+        K: PartialOrd,
+    {
+        self.entries.is_sorted_by(|a, b| a.key <= b.key)
+    }
+
+    /// Checks if this slice is sorted using the given comparator function.
+    #[inline]
+    pub fn is_sorted_by<'a, F>(&'a self, mut cmp: F) -> bool
+    where
+        F: FnMut(&'a K, &'a V, &'a K, &'a V) -> bool,
+    {
+        self.entries
+            .is_sorted_by(move |a, b| cmp(&a.key, &a.value, &b.key, &b.value))
+    }
+
+    /// Checks if this slice is sorted using the given sort-key function.
+    #[inline]
+    pub fn is_sorted_by_key<'a, F, T>(&'a self, mut sort_key: F) -> bool
+    where
+        F: FnMut(&'a K, &'a V) -> T,
+        T: PartialOrd,
+    {
+        self.entries
+            .is_sorted_by_key(move |a| sort_key(&a.key, &a.value))
+    }
+
+    /// Returns the index of the partition point of a sorted map according to the given predicate
+    /// (the index of the first element of the second partition).
+    ///
+    /// See [`slice::partition_point`] for more details.
+    ///
+    /// Computes in **O(log(n))** time.
+    #[must_use]
+    pub fn partition_point<P>(&self, mut pred: P) -> usize
+    where
+        P: FnMut(&K, &V) -> bool,
+    {
+        self.entries
+            .partition_point(move |a| pred(&a.key, &a.value))
+    }
+
+    /// Get an array of `N` key-value pairs by `N` indices
+    ///
+    /// Valid indices are *0 <= index < self.len()* and each index needs to be unique.
+    pub fn get_disjoint_mut<const N: usize>(
+        &mut self,
+        indices: [usize; N],
+    ) -> Result<[(&K, &mut V); N], GetDisjointMutError> {
+        let indices = indices.map(Some);
+        let key_values = self.get_disjoint_opt_mut(indices)?;
+        Ok(key_values.map(Option::unwrap))
+    }
+
+    #[allow(unsafe_code)]
+    pub(crate) fn get_disjoint_opt_mut<const N: usize>(
+        &mut self,
+        indices: [Option<usize>; N],
+    ) -> Result<[Option<(&K, &mut V)>; N], GetDisjointMutError> {
+        // SAFETY: Can't allow duplicate indices as we would return several mutable refs to the same data.
+        let len = self.len();
+        for i in 0..N {
+            if let Some(idx) = indices[i] {
+                if idx >= len {
+                    return Err(GetDisjointMutError::IndexOutOfBounds);
+                } else if indices[..i].contains(&Some(idx)) {
+                    return Err(GetDisjointMutError::OverlappingIndices);
+                }
+            }
+        }
+
+        let entries_ptr = self.entries.as_mut_ptr();
+        let out = indices.map(|idx_opt| {
+            match idx_opt {
+                Some(idx) => {
+                    // SAFETY: The base pointer is valid as it comes from a slice and the reference is always
+                    // in-bounds & unique as we've already checked the indices above.
+                    let kv = unsafe { (*(entries_ptr.add(idx))).ref_mut() };
+                    Some(kv)
+                }
+                None => None,
+            }
+        });
+
+        Ok(out)
+    }
+}
+
+impl<'a, K, V> IntoIterator for &'a Slice<K, V> {
+    type IntoIter = Iter<'a, K, V>;
+    type Item = (&'a K, &'a V);
+
+    fn into_iter(self) -> Self::IntoIter {
+        self.iter()
+    }
+}
+
+impl<'a, K, V> IntoIterator for &'a mut Slice<K, V> {
+    type IntoIter = IterMut<'a, K, V>;
+    type Item = (&'a K, &'a mut V);
+
+    fn into_iter(self) -> Self::IntoIter {
+        self.iter_mut()
+    }
+}
+
+impl<K, V> IntoIterator for Box<Slice<K, V>> {
+    type IntoIter = IntoIter<K, V>;
+    type Item = (K, V);
+
+    fn into_iter(self) -> Self::IntoIter {
+        IntoIter::new(self.into_entries())
+    }
+}
+
+impl<K, V> Default for &'_ Slice<K, V> {
+    fn default() -> Self {
+        Slice::from_slice(&[])
+    }
+}
+
+impl<K, V> Default for &'_ mut Slice<K, V> {
+    fn default() -> Self {
+        Slice::from_mut_slice(&mut [])
+    }
+}
+
+impl<K, V> Default for Box<Slice<K, V>> {
+    fn default() -> Self {
+        Slice::from_boxed(Box::default())
+    }
+}
+
+impl<K: Clone, V: Clone> Clone for Box<Slice<K, V>> {
+    fn clone(&self) -> Self {
+        Slice::from_boxed(self.entries.to_vec().into_boxed_slice())
+    }
+}
+
+impl<K: Copy, V: Copy> From<&Slice<K, V>> for Box<Slice<K, V>> {
+    fn from(slice: &Slice<K, V>) -> Self {
+        Slice::from_boxed(Box::from(&slice.entries))
+    }
+}
+
+impl<K: fmt::Debug, V: fmt::Debug> fmt::Debug for Slice<K, V> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_list().entries(self).finish()
+    }
+}
+
+impl<K, V, K2, V2> PartialEq<Slice<K2, V2>> for Slice<K, V>
+where
+    K: PartialEq<K2>,
+    V: PartialEq<V2>,
+{
+    fn eq(&self, other: &Slice<K2, V2>) -> bool {
+        slice_eq(&self.entries, &other.entries, |b1, b2| {
+            b1.key == b2.key && b1.value == b2.value
+        })
+    }
+}
+
+impl<K, V, K2, V2> PartialEq<[(K2, V2)]> for Slice<K, V>
+where
+    K: PartialEq<K2>,
+    V: PartialEq<V2>,
+{
+    fn eq(&self, other: &[(K2, V2)]) -> bool {
+        slice_eq(&self.entries, other, |b, t| b.key == t.0 && b.value == t.1)
+    }
+}
+
+impl<K, V, K2, V2> PartialEq<Slice<K2, V2>> for [(K, V)]
+where
+    K: PartialEq<K2>,
+    V: PartialEq<V2>,
+{
+    fn eq(&self, other: &Slice<K2, V2>) -> bool {
+        slice_eq(self, &other.entries, |t, b| t.0 == b.key && t.1 == b.value)
+    }
+}
+
+impl<K, V, K2, V2, const N: usize> PartialEq<[(K2, V2); N]> for Slice<K, V>
+where
+    K: PartialEq<K2>,
+    V: PartialEq<V2>,
+{
+    fn eq(&self, other: &[(K2, V2); N]) -> bool {
+        <Self as PartialEq<[_]>>::eq(self, other)
+    }
+}
+
+impl<K, V, const N: usize, K2, V2> PartialEq<Slice<K2, V2>> for [(K, V); N]
+where
+    K: PartialEq<K2>,
+    V: PartialEq<V2>,
+{
+    fn eq(&self, other: &Slice<K2, V2>) -> bool {
+        <[_] as PartialEq<_>>::eq(self, other)
+    }
+}
+
+impl<K: Eq, V: Eq> Eq for Slice<K, V> {}
+
+impl<K: PartialOrd, V: PartialOrd> PartialOrd for Slice<K, V> {
+    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
+        self.iter().partial_cmp(other)
+    }
+}
+
+impl<K: Ord, V: Ord> Ord for Slice<K, V> {
+    fn cmp(&self, other: &Self) -> Ordering {
+        self.iter().cmp(other)
+    }
+}
+
+impl<K: Hash, V: Hash> Hash for Slice<K, V> {
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        self.len().hash(state);
+        for (key, value) in self {
+            key.hash(state);
+            value.hash(state);
+        }
+    }
+}
+
+impl<K, V> Index<usize> for Slice<K, V> {
+    type Output = V;
+
+    fn index(&self, index: usize) -> &V {
+        &self.entries[index].value
+    }
+}
+
+impl<K, V> IndexMut<usize> for Slice<K, V> {
+    fn index_mut(&mut self, index: usize) -> &mut V {
+        &mut self.entries[index].value
+    }
+}
+
+// We can't have `impl<I: RangeBounds<usize>> Index<I>` because that conflicts
+// both upstream with `Index<usize>` and downstream with `Index<&Q>`.
+// Instead, we repeat the implementations for all the core range types.
+macro_rules! impl_index {
+    ($($range:ty),*) => {$(
+        impl<K, V, S> Index<$range> for IndexMap<K, V, S> {
+            type Output = Slice<K, V>;
+
+            fn index(&self, range: $range) -> &Self::Output {
+                Slice::from_slice(&self.as_entries()[range])
+            }
+        }
+
+        impl<K, V, S> IndexMut<$range> for IndexMap<K, V, S> {
+            fn index_mut(&mut self, range: $range) -> &mut Self::Output {
+                Slice::from_mut_slice(&mut self.as_entries_mut()[range])
+            }
+        }
+
+        impl<K, V> Index<$range> for Slice<K, V> {
+            type Output = Slice<K, V>;
+
+            fn index(&self, range: $range) -> &Self {
+                Self::from_slice(&self.entries[range])
+            }
+        }
+
+        impl<K, V> IndexMut<$range> for Slice<K, V> {
+            fn index_mut(&mut self, range: $range) -> &mut Self {
+                Self::from_mut_slice(&mut self.entries[range])
+            }
+        }
+    )*}
+}
+impl_index!(
+    ops::Range<usize>,
+    ops::RangeFrom<usize>,
+    ops::RangeFull,
+    ops::RangeInclusive<usize>,
+    ops::RangeTo<usize>,
+    ops::RangeToInclusive<usize>,
+    (Bound<usize>, Bound<usize>)
+);
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn slice_index() {
+        fn check(
+            vec_slice: &[(i32, i32)],
+            map_slice: &Slice<i32, i32>,
+            sub_slice: &Slice<i32, i32>,
+        ) {
+            assert_eq!(map_slice as *const _, sub_slice as *const _);
+            itertools::assert_equal(
+                vec_slice.iter().copied(),
+                map_slice.iter().map(|(&k, &v)| (k, v)),
+            );
+            itertools::assert_equal(vec_slice.iter().map(|(k, _)| k), map_slice.keys());
+            itertools::assert_equal(vec_slice.iter().map(|(_, v)| v), map_slice.values());
+        }
+
+        let vec: Vec<(i32, i32)> = (0..10).map(|i| (i, i * i)).collect();
+        let map: IndexMap<i32, i32> = vec.iter().cloned().collect();
+        let slice = map.as_slice();
+
+        // RangeFull
+        check(&vec[..], &map[..], &slice[..]);
+
+        for i in 0usize..10 {
+            // Index
+            assert_eq!(vec[i].1, map[i]);
+            assert_eq!(vec[i].1, slice[i]);
+            assert_eq!(map[&(i as i32)], map[i]);
+            assert_eq!(map[&(i as i32)], slice[i]);
+
+            // RangeFrom
+            check(&vec[i..], &map[i..], &slice[i..]);
+
+            // RangeTo
+            check(&vec[..i], &map[..i], &slice[..i]);
+
+            // RangeToInclusive
+            check(&vec[..=i], &map[..=i], &slice[..=i]);
+
+            // (Bound<usize>, Bound<usize>)
+            let bounds = (Bound::Excluded(i), Bound::Unbounded);
+            check(&vec[i + 1..], &map[bounds], &slice[bounds]);
+
+            for j in i..=10 {
+                // Range
+                check(&vec[i..j], &map[i..j], &slice[i..j]);
+            }
+
+            for j in i..10 {
+                // RangeInclusive
+                check(&vec[i..=j], &map[i..=j], &slice[i..=j]);
+            }
+        }
+    }
+
+    #[test]
+    fn slice_index_mut() {
+        fn check_mut(
+            vec_slice: &[(i32, i32)],
+            map_slice: &mut Slice<i32, i32>,
+            sub_slice: &mut Slice<i32, i32>,
+        ) {
+            assert_eq!(map_slice, sub_slice);
+            itertools::assert_equal(
+                vec_slice.iter().copied(),
+                map_slice.iter_mut().map(|(&k, &mut v)| (k, v)),
+            );
+            itertools::assert_equal(
+                vec_slice.iter().map(|&(_, v)| v),
+                map_slice.values_mut().map(|&mut v| v),
+            );
+        }
+
+        let vec: Vec<(i32, i32)> = (0..10).map(|i| (i, i * i)).collect();
+        let mut map: IndexMap<i32, i32> = vec.iter().cloned().collect();
+        let mut map2 = map.clone();
+        let slice = map2.as_mut_slice();
+
+        // RangeFull
+        check_mut(&vec[..], &mut map[..], &mut slice[..]);
+
+        for i in 0usize..10 {
+            // IndexMut
+            assert_eq!(&mut map[i], &mut slice[i]);
+
+            // RangeFrom
+            check_mut(&vec[i..], &mut map[i..], &mut slice[i..]);
+
+            // RangeTo
+            check_mut(&vec[..i], &mut map[..i], &mut slice[..i]);
+
+            // RangeToInclusive
+            check_mut(&vec[..=i], &mut map[..=i], &mut slice[..=i]);
+
+            // (Bound<usize>, Bound<usize>)
+            let bounds = (Bound::Excluded(i), Bound::Unbounded);
+            check_mut(&vec[i + 1..], &mut map[bounds], &mut slice[bounds]);
+
+            for j in i..=10 {
+                // Range
+                check_mut(&vec[i..j], &mut map[i..j], &mut slice[i..j]);
+            }
+
+            for j in i..10 {
+                // RangeInclusive
+                check_mut(&vec[i..=j], &mut map[i..=j], &mut slice[i..=j]);
+            }
+        }
+    }
+
+    #[test]
+    fn slice_new() {
+        let slice: &Slice<i32, i32> = Slice::new();
+        assert!(slice.is_empty());
+        assert_eq!(slice.len(), 0);
+    }
+
+    #[test]
+    fn slice_new_mut() {
+        let slice: &mut Slice<i32, i32> = Slice::new_mut();
+        assert!(slice.is_empty());
+        assert_eq!(slice.len(), 0);
+    }
+
+    #[test]
+    fn slice_get_index_mut() {
+        let mut map: IndexMap<i32, i32> = (0..10).map(|i| (i, i * i)).collect();
+        let slice: &mut Slice<i32, i32> = map.as_mut_slice();
+
+        {
+            let (key, value) = slice.get_index_mut(0).unwrap();
+            assert_eq!(*key, 0);
+            assert_eq!(*value, 0);
+
+            *value = 11;
+        }
+
+        assert_eq!(slice[0], 11);
+
+        {
+            let result = slice.get_index_mut(11);
+            assert!(result.is_none());
+        }
+    }
+
+    #[test]
+    fn slice_split_first() {
+        let slice: &mut Slice<i32, i32> = Slice::new_mut();
+        let result = slice.split_first();
+        assert!(result.is_none());
+
+        let mut map: IndexMap<i32, i32> = (0..10).map(|i| (i, i * i)).collect();
+        let slice: &mut Slice<i32, i32> = map.as_mut_slice();
+
+        {
+            let (first, rest) = slice.split_first().unwrap();
+            assert_eq!(first, (&0, &0));
+            assert_eq!(rest.len(), 9);
+        }
+        assert_eq!(slice.len(), 10);
+    }
+
+    #[test]
+    fn slice_split_first_mut() {
+        let slice: &mut Slice<i32, i32> = Slice::new_mut();
+        let result = slice.split_first_mut();
+        assert!(result.is_none());
+
+        let mut map: IndexMap<i32, i32> = (0..10).map(|i| (i, i * i)).collect();
+        let slice: &mut Slice<i32, i32> = map.as_mut_slice();
+
+        {
+            let (first, rest) = slice.split_first_mut().unwrap();
+            assert_eq!(first, (&0, &mut 0));
+            assert_eq!(rest.len(), 9);
+
+            *first.1 = 11;
+        }
+        assert_eq!(slice.len(), 10);
+        assert_eq!(slice[0], 11);
+    }
+
+    #[test]
+    fn slice_split_last() {
+        let slice: &mut Slice<i32, i32> = Slice::new_mut();
+        let result = slice.split_last();
+        assert!(result.is_none());
+
+        let mut map: IndexMap<i32, i32> = (0..10).map(|i| (i, i * i)).collect();
+        let slice: &mut Slice<i32, i32> = map.as_mut_slice();
+
+        {
+            let (last, rest) = slice.split_last().unwrap();
+            assert_eq!(last, (&9, &81));
+            assert_eq!(rest.len(), 9);
+        }
+        assert_eq!(slice.len(), 10);
+    }
+
+    #[test]
+    fn slice_split_last_mut() {
+        let slice: &mut Slice<i32, i32> = Slice::new_mut();
+        let result = slice.split_last_mut();
+        assert!(result.is_none());
+
+        let mut map: IndexMap<i32, i32> = (0..10).map(|i| (i, i * i)).collect();
+        let slice: &mut Slice<i32, i32> = map.as_mut_slice();
+
+        {
+            let (last, rest) = slice.split_last_mut().unwrap();
+            assert_eq!(last, (&9, &mut 81));
+            assert_eq!(rest.len(), 9);
+
+            *last.1 = 100;
+        }
+
+        assert_eq!(slice.len(), 10);
+        assert_eq!(slice[slice.len() - 1], 100);
+    }
+
+    #[test]
+    fn slice_get_range() {
+        let mut map: IndexMap<i32, i32> = (0..10).map(|i| (i, i * i)).collect();
+        let slice: &mut Slice<i32, i32> = map.as_mut_slice();
+        let subslice = slice.get_range(3..6).unwrap();
+        assert_eq!(subslice.len(), 3);
+        assert_eq!(subslice, &[(3, 9), (4, 16), (5, 25)]);
+    }
+}