Adding upstream version 110.0.1.upstream/110.0.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

3 files changed, 1351 insertions, 0 deletions

diff --git a/third_party/rust/indexmap/src/rayon/map.rs b/third_party/rust/indexmap/src/rayon/map.rs
new file mode 100644
index 0000000000..8819f13ed7
--- /dev/null
+++ b/third_party/rust/indexmap/src/rayon/map.rs
@@ -0,0 +1,583 @@
+//! Parallel iterator types for `IndexMap` with [rayon](https://docs.rs/rayon/1.0/rayon).
+//!
+//! You will rarely need to interact with this module directly unless you need to name one of the
+//! iterator types.
+//!
+//! Requires crate feature `"rayon"`
+
+use super::collect;
+use rayon::iter::plumbing::{Consumer, ProducerCallback, UnindexedConsumer};
+use rayon::prelude::*;
+
+use crate::vec::Vec;
+use core::cmp::Ordering;
+use core::fmt;
+use core::hash::{BuildHasher, Hash};
+use core::ops::RangeBounds;
+
+use crate::Bucket;
+use crate::Entries;
+use crate::IndexMap;
+
+/// Requires crate feature `"rayon"`.
+impl<K, V, S> IntoParallelIterator for IndexMap<K, V, S>
+where
+    K: Send,
+    V: Send,
+{
+    type Item = (K, V);
+    type Iter = IntoParIter<K, V>;
+
+    fn into_par_iter(self) -> Self::Iter {
+        IntoParIter {
+            entries: self.into_entries(),
+        }
+    }
+}
+
+/// A parallel owning iterator over the entries of a `IndexMap`.
+///
+/// This `struct` is created by the [`into_par_iter`] method on [`IndexMap`]
+/// (provided by rayon's `IntoParallelIterator` trait). See its documentation for more.
+///
+/// [`into_par_iter`]: ../struct.IndexMap.html#method.into_par_iter
+/// [`IndexMap`]: ../struct.IndexMap.html
+pub struct IntoParIter<K, V> {
+    entries: Vec<Bucket<K, V>>,
+}
+
+impl<K: fmt::Debug, V: fmt::Debug> fmt::Debug for IntoParIter<K, V> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let iter = self.entries.iter().map(Bucket::refs);
+        f.debug_list().entries(iter).finish()
+    }
+}
+
+impl<K: Send, V: Send> ParallelIterator for IntoParIter<K, V> {
+    type Item = (K, V);
+
+    parallel_iterator_methods!(Bucket::key_value);
+}
+
+impl<K: Send, V: Send> IndexedParallelIterator for IntoParIter<K, V> {
+    indexed_parallel_iterator_methods!(Bucket::key_value);
+}
+
+/// Requires crate feature `"rayon"`.
+impl<'a, K, V, S> IntoParallelIterator for &'a IndexMap<K, V, S>
+where
+    K: Sync,
+    V: Sync,
+{
+    type Item = (&'a K, &'a V);
+    type Iter = ParIter<'a, K, V>;
+
+    fn into_par_iter(self) -> Self::Iter {
+        ParIter {
+            entries: self.as_entries(),
+        }
+    }
+}
+
+/// A parallel iterator over the entries of a `IndexMap`.
+///
+/// This `struct` is created by the [`par_iter`] method on [`IndexMap`]
+/// (provided by rayon's `IntoParallelRefIterator` trait). See its documentation for more.
+///
+/// [`par_iter`]: ../struct.IndexMap.html#method.par_iter
+/// [`IndexMap`]: ../struct.IndexMap.html
+pub struct ParIter<'a, K, V> {
+    entries: &'a [Bucket<K, V>],
+}
+
+impl<K, V> Clone for ParIter<'_, K, V> {
+    fn clone(&self) -> Self {
+        ParIter { ..*self }
+    }
+}
+
+impl<K: fmt::Debug, V: fmt::Debug> fmt::Debug for ParIter<'_, K, V> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let iter = self.entries.iter().map(Bucket::refs);
+        f.debug_list().entries(iter).finish()
+    }
+}
+
+impl<'a, K: Sync, V: Sync> ParallelIterator for ParIter<'a, K, V> {
+    type Item = (&'a K, &'a V);
+
+    parallel_iterator_methods!(Bucket::refs);
+}
+
+impl<K: Sync, V: Sync> IndexedParallelIterator for ParIter<'_, K, V> {
+    indexed_parallel_iterator_methods!(Bucket::refs);
+}
+
+/// Requires crate feature `"rayon"`.
+impl<'a, K, V, S> IntoParallelIterator for &'a mut IndexMap<K, V, S>
+where
+    K: Sync + Send,
+    V: Send,
+{
+    type Item = (&'a K, &'a mut V);
+    type Iter = ParIterMut<'a, K, V>;
+
+    fn into_par_iter(self) -> Self::Iter {
+        ParIterMut {
+            entries: self.as_entries_mut(),
+        }
+    }
+}
+
+/// A parallel mutable iterator over the entries of a `IndexMap`.
+///
+/// This `struct` is created by the [`par_iter_mut`] method on [`IndexMap`]
+/// (provided by rayon's `IntoParallelRefMutIterator` trait). See its documentation for more.
+///
+/// [`par_iter_mut`]: ../struct.IndexMap.html#method.par_iter_mut
+/// [`IndexMap`]: ../struct.IndexMap.html
+pub struct ParIterMut<'a, K, V> {
+    entries: &'a mut [Bucket<K, V>],
+}
+
+impl<K: fmt::Debug, V: fmt::Debug> fmt::Debug for ParIterMut<'_, K, V> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let iter = self.entries.iter().map(Bucket::refs);
+        f.debug_list().entries(iter).finish()
+    }
+}
+
+impl<'a, K: Sync + Send, V: Send> ParallelIterator for ParIterMut<'a, K, V> {
+    type Item = (&'a K, &'a mut V);
+
+    parallel_iterator_methods!(Bucket::ref_mut);
+}
+
+impl<K: Sync + Send, V: Send> IndexedParallelIterator for ParIterMut<'_, K, V> {
+    indexed_parallel_iterator_methods!(Bucket::ref_mut);
+}
+
+/// Requires crate feature `"rayon"`.
+impl<'a, K, V, S> ParallelDrainRange<usize> for &'a mut IndexMap<K, V, S>
+where
+    K: Send,
+    V: Send,
+{
+    type Item = (K, V);
+    type Iter = ParDrain<'a, K, V>;
+
+    fn par_drain<R: RangeBounds<usize>>(self, range: R) -> Self::Iter {
+        ParDrain {
+            entries: self.core.par_drain(range),
+        }
+    }
+}
+
+/// A parallel draining iterator over the entries of a `IndexMap`.
+///
+/// This `struct` is created by the [`par_drain`] method on [`IndexMap`]
+/// (provided by rayon's `ParallelDrainRange` trait). See its documentation for more.
+///
+/// [`par_drain`]: ../struct.IndexMap.html#method.par_drain
+/// [`IndexMap`]: ../struct.IndexMap.html
+pub struct ParDrain<'a, K: Send, V: Send> {
+    entries: rayon::vec::Drain<'a, Bucket<K, V>>,
+}
+
+impl<K: Send, V: Send> ParallelIterator for ParDrain<'_, K, V> {
+    type Item = (K, V);
+
+    parallel_iterator_methods!(Bucket::key_value);
+}
+
+impl<K: Send, V: Send> IndexedParallelIterator for ParDrain<'_, K, V> {
+    indexed_parallel_iterator_methods!(Bucket::key_value);
+}
+
+/// Parallel iterator methods and other parallel methods.
+///
+/// The following methods **require crate feature `"rayon"`**.
+///
+/// See also the `IntoParallelIterator` implementations.
+impl<K, V, S> IndexMap<K, V, S>
+where
+    K: Sync,
+    V: Sync,
+{
+    /// Return a parallel iterator over the keys of the map.
+    ///
+    /// While parallel iterators can process items in any order, their relative order
+    /// in the map is still preserved for operations like `reduce` and `collect`.
+    pub fn par_keys(&self) -> ParKeys<'_, K, V> {
+        ParKeys {
+            entries: self.as_entries(),
+        }
+    }
+
+    /// Return a parallel iterator over the values of the map.
+    ///
+    /// While parallel iterators can process items in any order, their relative order
+    /// in the map is still preserved for operations like `reduce` and `collect`.
+    pub fn par_values(&self) -> ParValues<'_, K, V> {
+        ParValues {
+            entries: self.as_entries(),
+        }
+    }
+}
+
+impl<K, V, S> IndexMap<K, V, S>
+where
+    K: Hash + Eq + Sync,
+    V: Sync,
+    S: BuildHasher,
+{
+    /// Returns `true` if `self` contains all of the same key-value pairs as `other`,
+    /// regardless of each map's indexed order, determined in parallel.
+    pub fn par_eq<V2, S2>(&self, other: &IndexMap<K, V2, S2>) -> bool
+    where
+        V: PartialEq<V2>,
+        V2: Sync,
+        S2: BuildHasher + Sync,
+    {
+        self.len() == other.len()
+            && self
+                .par_iter()
+                .all(move |(key, value)| other.get(key).map_or(false, |v| *value == *v))
+    }
+}
+
+/// A parallel iterator over the keys of a `IndexMap`.
+///
+/// This `struct` is created by the [`par_keys`] method on [`IndexMap`]. See its
+/// documentation for more.
+///
+/// [`par_keys`]: ../struct.IndexMap.html#method.par_keys
+/// [`IndexMap`]: ../struct.IndexMap.html
+pub struct ParKeys<'a, K, V> {
+    entries: &'a [Bucket<K, V>],
+}
+
+impl<K, V> Clone for ParKeys<'_, K, V> {
+    fn clone(&self) -> Self {
+        ParKeys { ..*self }
+    }
+}
+
+impl<K: fmt::Debug, V> fmt::Debug for ParKeys<'_, K, V> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let iter = self.entries.iter().map(Bucket::key_ref);
+        f.debug_list().entries(iter).finish()
+    }
+}
+
+impl<'a, K: Sync, V: Sync> ParallelIterator for ParKeys<'a, K, V> {
+    type Item = &'a K;
+
+    parallel_iterator_methods!(Bucket::key_ref);
+}
+
+impl<K: Sync, V: Sync> IndexedParallelIterator for ParKeys<'_, K, V> {
+    indexed_parallel_iterator_methods!(Bucket::key_ref);
+}
+
+/// A parallel iterator over the values of a `IndexMap`.
+///
+/// This `struct` is created by the [`par_values`] method on [`IndexMap`]. See its
+/// documentation for more.
+///
+/// [`par_values`]: ../struct.IndexMap.html#method.par_values
+/// [`IndexMap`]: ../struct.IndexMap.html
+pub struct ParValues<'a, K, V> {
+    entries: &'a [Bucket<K, V>],
+}
+
+impl<K, V> Clone for ParValues<'_, K, V> {
+    fn clone(&self) -> Self {
+        ParValues { ..*self }
+    }
+}
+
+impl<K, V: fmt::Debug> fmt::Debug for ParValues<'_, K, V> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let iter = self.entries.iter().map(Bucket::value_ref);
+        f.debug_list().entries(iter).finish()
+    }
+}
+
+impl<'a, K: Sync, V: Sync> ParallelIterator for ParValues<'a, K, V> {
+    type Item = &'a V;
+
+    parallel_iterator_methods!(Bucket::value_ref);
+}
+
+impl<K: Sync, V: Sync> IndexedParallelIterator for ParValues<'_, K, V> {
+    indexed_parallel_iterator_methods!(Bucket::value_ref);
+}
+
+/// Requires crate feature `"rayon"`.
+impl<K, V, S> IndexMap<K, V, S>
+where
+    K: Send,
+    V: Send,
+{
+    /// Return a parallel iterator over mutable references to the values of the map
+    ///
+    /// While parallel iterators can process items in any order, their relative order
+    /// in the map is still preserved for operations like `reduce` and `collect`.
+    pub fn par_values_mut(&mut self) -> ParValuesMut<'_, K, V> {
+        ParValuesMut {
+            entries: self.as_entries_mut(),
+        }
+    }
+}
+
+impl<K, V, S> IndexMap<K, V, S>
+where
+    K: Hash + Eq + Send,
+    V: Send,
+    S: BuildHasher,
+{
+    /// Sort the map’s key-value pairs in parallel, by the default ordering of the keys.
+    pub fn par_sort_keys(&mut self)
+    where
+        K: Ord,
+    {
+        self.with_entries(|entries| {
+            entries.par_sort_by(|a, b| K::cmp(&a.key, &b.key));
+        });
+    }
+
+    /// Sort the map’s key-value pairs in place and in parallel, using the comparison
+    /// function `cmp`.
+    ///
+    /// The comparison function receives two key and value pairs to compare (you
+    /// can sort by keys or values or their combination as needed).
+    pub fn par_sort_by<F>(&mut self, cmp: F)
+    where
+        F: Fn(&K, &V, &K, &V) -> Ordering + Sync,
+    {
+        self.with_entries(|entries| {
+            entries.par_sort_by(move |a, b| cmp(&a.key, &a.value, &b.key, &b.value));
+        });
+    }
+
+    /// Sort the key-value pairs of the map in parallel and return a by-value parallel
+    /// iterator of the key-value pairs with the result.
+    pub fn par_sorted_by<F>(self, cmp: F) -> IntoParIter<K, V>
+    where
+        F: Fn(&K, &V, &K, &V) -> Ordering + Sync,
+    {
+        let mut entries = self.into_entries();
+        entries.par_sort_by(move |a, b| cmp(&a.key, &a.value, &b.key, &b.value));
+        IntoParIter { entries }
+    }
+
+    /// Sort the map's key-value pairs in parallel, by the default ordering of the keys.
+    pub fn par_sort_unstable_keys(&mut self)
+    where
+        K: Ord,
+    {
+        self.with_entries(|entries| {
+            entries.par_sort_unstable_by(|a, b| K::cmp(&a.key, &b.key));
+        });
+    }
+
+    /// Sort the map's key-value pairs in place and in parallel, using the comparison
+    /// function `cmp`.
+    ///
+    /// The comparison function receives two key and value pairs to compare (you
+    /// can sort by keys or values or their combination as needed).
+    pub fn par_sort_unstable_by<F>(&mut self, cmp: F)
+    where
+        F: Fn(&K, &V, &K, &V) -> Ordering + Sync,
+    {
+        self.with_entries(|entries| {
+            entries.par_sort_unstable_by(move |a, b| cmp(&a.key, &a.value, &b.key, &b.value));
+        });
+    }
+
+    /// Sort the key-value pairs of the map in parallel and return a by-value parallel
+    /// iterator of the key-value pairs with the result.
+    pub fn par_sorted_unstable_by<F>(self, cmp: F) -> IntoParIter<K, V>
+    where
+        F: Fn(&K, &V, &K, &V) -> Ordering + Sync,
+    {
+        let mut entries = self.into_entries();
+        entries.par_sort_unstable_by(move |a, b| cmp(&a.key, &a.value, &b.key, &b.value));
+        IntoParIter { entries }
+    }
+}
+
+/// A parallel mutable iterator over the values of a `IndexMap`.
+///
+/// This `struct` is created by the [`par_values_mut`] method on [`IndexMap`]. See its
+/// documentation for more.
+///
+/// [`par_values_mut`]: ../struct.IndexMap.html#method.par_values_mut
+/// [`IndexMap`]: ../struct.IndexMap.html
+pub struct ParValuesMut<'a, K, V> {
+    entries: &'a mut [Bucket<K, V>],
+}
+
+impl<K, V: fmt::Debug> fmt::Debug for ParValuesMut<'_, K, V> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let iter = self.entries.iter().map(Bucket::value_ref);
+        f.debug_list().entries(iter).finish()
+    }
+}
+
+impl<'a, K: Send, V: Send> ParallelIterator for ParValuesMut<'a, K, V> {
+    type Item = &'a mut V;
+
+    parallel_iterator_methods!(Bucket::value_mut);
+}
+
+impl<K: Send, V: Send> IndexedParallelIterator for ParValuesMut<'_, K, V> {
+    indexed_parallel_iterator_methods!(Bucket::value_mut);
+}
+
+/// Requires crate feature `"rayon"`.
+impl<K, V, S> FromParallelIterator<(K, V)> for IndexMap<K, V, S>
+where
+    K: Eq + Hash + Send,
+    V: Send,
+    S: BuildHasher + Default + Send,
+{
+    fn from_par_iter<I>(iter: I) -> Self
+    where
+        I: IntoParallelIterator<Item = (K, V)>,
+    {
+        let list = collect(iter);
+        let len = list.iter().map(Vec::len).sum();
+        let mut map = Self::with_capacity_and_hasher(len, S::default());
+        for vec in list {
+            map.extend(vec);
+        }
+        map
+    }
+}
+
+/// Requires crate feature `"rayon"`.
+impl<K, V, S> ParallelExtend<(K, V)> for IndexMap<K, V, S>
+where
+    K: Eq + Hash + Send,
+    V: Send,
+    S: BuildHasher + Send,
+{
+    fn par_extend<I>(&mut self, iter: I)
+    where
+        I: IntoParallelIterator<Item = (K, V)>,
+    {
+        for vec in collect(iter) {
+            self.extend(vec);
+        }
+    }
+}
+
+/// Requires crate feature `"rayon"`.
+impl<'a, K: 'a, V: 'a, S> ParallelExtend<(&'a K, &'a V)> for IndexMap<K, V, S>
+where
+    K: Copy + Eq + Hash + Send + Sync,
+    V: Copy + Send + Sync,
+    S: BuildHasher + Send,
+{
+    fn par_extend<I>(&mut self, iter: I)
+    where
+        I: IntoParallelIterator<Item = (&'a K, &'a V)>,
+    {
+        for vec in collect(iter) {
+            self.extend(vec);
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::string::String;
+
+    #[test]
+    fn insert_order() {
+        let insert = [0, 4, 2, 12, 8, 7, 11, 5, 3, 17, 19, 22, 23];
+        let mut map = IndexMap::new();
+
+        for &elt in &insert {
+            map.insert(elt, ());
+        }
+
+        assert_eq!(map.par_keys().count(), map.len());
+        assert_eq!(map.par_keys().count(), insert.len());
+        insert.par_iter().zip(map.par_keys()).for_each(|(a, b)| {
+            assert_eq!(a, b);
+        });
+        (0..insert.len())
+            .into_par_iter()
+            .zip(map.par_keys())
+            .for_each(|(i, k)| {
+                assert_eq!(map.get_index(i).unwrap().0, k);
+            });
+    }
+
+    #[test]
+    fn partial_eq_and_eq() {
+        let mut map_a = IndexMap::new();
+        map_a.insert(1, "1");
+        map_a.insert(2, "2");
+        let mut map_b = map_a.clone();
+        assert!(map_a.par_eq(&map_b));
+        map_b.swap_remove(&1);
+        assert!(!map_a.par_eq(&map_b));
+        map_b.insert(3, "3");
+        assert!(!map_a.par_eq(&map_b));
+
+        let map_c: IndexMap<_, String> =
+            map_b.into_par_iter().map(|(k, v)| (k, v.into())).collect();
+        assert!(!map_a.par_eq(&map_c));
+        assert!(!map_c.par_eq(&map_a));
+    }
+
+    #[test]
+    fn extend() {
+        let mut map = IndexMap::new();
+        map.par_extend(vec![(&1, &2), (&3, &4)]);
+        map.par_extend(vec![(5, 6)]);
+        assert_eq!(
+            map.into_par_iter().collect::<Vec<_>>(),
+            vec![(1, 2), (3, 4), (5, 6)]
+        );
+    }
+
+    #[test]
+    fn keys() {
+        let vec = vec![(1, 'a'), (2, 'b'), (3, 'c')];
+        let map: IndexMap<_, _> = vec.into_par_iter().collect();
+        let keys: Vec<_> = map.par_keys().copied().collect();
+        assert_eq!(keys.len(), 3);
+        assert!(keys.contains(&1));
+        assert!(keys.contains(&2));
+        assert!(keys.contains(&3));
+    }
+
+    #[test]
+    fn values() {
+        let vec = vec![(1, 'a'), (2, 'b'), (3, 'c')];
+        let map: IndexMap<_, _> = vec.into_par_iter().collect();
+        let values: Vec<_> = map.par_values().copied().collect();
+        assert_eq!(values.len(), 3);
+        assert!(values.contains(&'a'));
+        assert!(values.contains(&'b'));
+        assert!(values.contains(&'c'));
+    }
+
+    #[test]
+    fn values_mut() {
+        let vec = vec![(1, 1), (2, 2), (3, 3)];
+        let mut map: IndexMap<_, _> = vec.into_par_iter().collect();
+        map.par_values_mut().for_each(|value| *value *= 2);
+        let values: Vec<_> = map.par_values().copied().collect();
+        assert_eq!(values.len(), 3);
+        assert!(values.contains(&2));
+        assert!(values.contains(&4));
+        assert!(values.contains(&6));
+    }
+}
diff --git a/third_party/rust/indexmap/src/rayon/mod.rs b/third_party/rust/indexmap/src/rayon/mod.rs
new file mode 100644
index 0000000000..ebb1ac2d1e
--- /dev/null
+++ b/third_party/rust/indexmap/src/rayon/mod.rs
@@ -0,0 +1,27 @@
+use rayon::prelude::*;
+
+use alloc::collections::LinkedList;
+
+use crate::vec::Vec;
+
+pub mod map;
+pub mod set;
+
+// This form of intermediate collection is also how Rayon collects `HashMap`.
+// Note that the order will also be preserved!
+fn collect<I: IntoParallelIterator>(iter: I) -> LinkedList<Vec<I::Item>> {
+    iter.into_par_iter()
+        .fold(Vec::new, |mut vec, elem| {
+            vec.push(elem);
+            vec
+        })
+        .map(|vec| {
+            let mut list = LinkedList::new();
+            list.push_back(vec);
+            list
+        })
+        .reduce(LinkedList::new, |mut list1, mut list2| {
+            list1.append(&mut list2);
+            list1
+        })
+}
diff --git a/third_party/rust/indexmap/src/rayon/set.rs b/third_party/rust/indexmap/src/rayon/set.rs
new file mode 100644
index 0000000000..6749dc0d7f
--- /dev/null
+++ b/third_party/rust/indexmap/src/rayon/set.rs
@@ -0,0 +1,741 @@
+//! Parallel iterator types for `IndexSet` with [rayon](https://docs.rs/rayon/1.0/rayon).
+//!
+//! You will rarely need to interact with this module directly unless you need to name one of the
+//! iterator types.
+//!
+//! Requires crate feature `"rayon"`.
+
+use super::collect;
+use rayon::iter::plumbing::{Consumer, ProducerCallback, UnindexedConsumer};
+use rayon::prelude::*;
+
+use crate::vec::Vec;
+use core::cmp::Ordering;
+use core::fmt;
+use core::hash::{BuildHasher, Hash};
+use core::ops::RangeBounds;
+
+use crate::Entries;
+use crate::IndexSet;
+
+type Bucket<T> = crate::Bucket<T, ()>;
+
+/// Requires crate feature `"rayon"`.
+impl<T, S> IntoParallelIterator for IndexSet<T, S>
+where
+    T: Send,
+{
+    type Item = T;
+    type Iter = IntoParIter<T>;
+
+    fn into_par_iter(self) -> Self::Iter {
+        IntoParIter {
+            entries: self.into_entries(),
+        }
+    }
+}
+
+/// A parallel owning iterator over the items of a `IndexSet`.
+///
+/// This `struct` is created by the [`into_par_iter`] method on [`IndexSet`]
+/// (provided by rayon's `IntoParallelIterator` trait). See its documentation for more.
+///
+/// [`IndexSet`]: ../struct.IndexSet.html
+/// [`into_par_iter`]: ../struct.IndexSet.html#method.into_par_iter
+pub struct IntoParIter<T> {
+    entries: Vec<Bucket<T>>,
+}
+
+impl<T: fmt::Debug> fmt::Debug for IntoParIter<T> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let iter = self.entries.iter().map(Bucket::key_ref);
+        f.debug_list().entries(iter).finish()
+    }
+}
+
+impl<T: Send> ParallelIterator for IntoParIter<T> {
+    type Item = T;
+
+    parallel_iterator_methods!(Bucket::key);
+}
+
+impl<T: Send> IndexedParallelIterator for IntoParIter<T> {
+    indexed_parallel_iterator_methods!(Bucket::key);
+}
+
+/// Requires crate feature `"rayon"`.
+impl<'a, T, S> IntoParallelIterator for &'a IndexSet<T, S>
+where
+    T: Sync,
+{
+    type Item = &'a T;
+    type Iter = ParIter<'a, T>;
+
+    fn into_par_iter(self) -> Self::Iter {
+        ParIter {
+            entries: self.as_entries(),
+        }
+    }
+}
+
+/// A parallel iterator over the items of a `IndexSet`.
+///
+/// This `struct` is created by the [`par_iter`] method on [`IndexSet`]
+/// (provided by rayon's `IntoParallelRefIterator` trait). See its documentation for more.
+///
+/// [`IndexSet`]: ../struct.IndexSet.html
+/// [`par_iter`]: ../struct.IndexSet.html#method.par_iter
+pub struct ParIter<'a, T> {
+    entries: &'a [Bucket<T>],
+}
+
+impl<T> Clone for ParIter<'_, T> {
+    fn clone(&self) -> Self {
+        ParIter { ..*self }
+    }
+}
+
+impl<T: fmt::Debug> fmt::Debug for ParIter<'_, T> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let iter = self.entries.iter().map(Bucket::key_ref);
+        f.debug_list().entries(iter).finish()
+    }
+}
+
+impl<'a, T: Sync> ParallelIterator for ParIter<'a, T> {
+    type Item = &'a T;
+
+    parallel_iterator_methods!(Bucket::key_ref);
+}
+
+impl<T: Sync> IndexedParallelIterator for ParIter<'_, T> {
+    indexed_parallel_iterator_methods!(Bucket::key_ref);
+}
+
+/// Requires crate feature `"rayon"`.
+impl<'a, T, S> ParallelDrainRange<usize> for &'a mut IndexSet<T, S>
+where
+    T: Send,
+{
+    type Item = T;
+    type Iter = ParDrain<'a, T>;
+
+    fn par_drain<R: RangeBounds<usize>>(self, range: R) -> Self::Iter {
+        ParDrain {
+            entries: self.map.core.par_drain(range),
+        }
+    }
+}
+
+/// A parallel draining iterator over the items of a `IndexSet`.
+///
+/// This `struct` is created by the [`par_drain`] method on [`IndexSet`]
+/// (provided by rayon's `ParallelDrainRange` trait). See its documentation for more.
+///
+/// [`par_drain`]: ../struct.IndexSet.html#method.par_drain
+/// [`IndexSet`]: ../struct.IndexSet.html
+pub struct ParDrain<'a, T: Send> {
+    entries: rayon::vec::Drain<'a, Bucket<T>>,
+}
+
+impl<T: Send> ParallelIterator for ParDrain<'_, T> {
+    type Item = T;
+
+    parallel_iterator_methods!(Bucket::key);
+}
+
+impl<T: Send> IndexedParallelIterator for ParDrain<'_, T> {
+    indexed_parallel_iterator_methods!(Bucket::key);
+}
+
+/// Parallel iterator methods and other parallel methods.
+///
+/// The following methods **require crate feature `"rayon"`**.
+///
+/// See also the `IntoParallelIterator` implementations.
+impl<T, S> IndexSet<T, S>
+where
+    T: Hash + Eq + Sync,
+    S: BuildHasher + Sync,
+{
+    /// Return a parallel iterator over the values that are in `self` but not `other`.
+    ///
+    /// While parallel iterators can process items in any order, their relative order
+    /// in the `self` set is still preserved for operations like `reduce` and `collect`.
+    pub fn par_difference<'a, S2>(
+        &'a self,
+        other: &'a IndexSet<T, S2>,
+    ) -> ParDifference<'a, T, S, S2>
+    where
+        S2: BuildHasher + Sync,
+    {
+        ParDifference {
+            set1: self,
+            set2: other,
+        }
+    }
+
+    /// Return a parallel iterator over the values that are in `self` or `other`,
+    /// but not in both.
+    ///
+    /// While parallel iterators can process items in any order, their relative order
+    /// in the sets is still preserved for operations like `reduce` and `collect`.
+    /// Values from `self` are produced in their original order, followed by
+    /// values from `other` in their original order.
+    pub fn par_symmetric_difference<'a, S2>(
+        &'a self,
+        other: &'a IndexSet<T, S2>,
+    ) -> ParSymmetricDifference<'a, T, S, S2>
+    where
+        S2: BuildHasher + Sync,
+    {
+        ParSymmetricDifference {
+            set1: self,
+            set2: other,
+        }
+    }
+
+    /// Return a parallel iterator over the values that are in both `self` and `other`.
+    ///
+    /// While parallel iterators can process items in any order, their relative order
+    /// in the `self` set is still preserved for operations like `reduce` and `collect`.
+    pub fn par_intersection<'a, S2>(
+        &'a self,
+        other: &'a IndexSet<T, S2>,
+    ) -> ParIntersection<'a, T, S, S2>
+    where
+        S2: BuildHasher + Sync,
+    {
+        ParIntersection {
+            set1: self,
+            set2: other,
+        }
+    }
+
+    /// Return a parallel iterator over all values that are in `self` or `other`.
+    ///
+    /// While parallel iterators can process items in any order, their relative order
+    /// in the sets is still preserved for operations like `reduce` and `collect`.
+    /// Values from `self` are produced in their original order, followed by
+    /// values that are unique to `other` in their original order.
+    pub fn par_union<'a, S2>(&'a self, other: &'a IndexSet<T, S2>) -> ParUnion<'a, T, S, S2>
+    where
+        S2: BuildHasher + Sync,
+    {
+        ParUnion {
+            set1: self,
+            set2: other,
+        }
+    }
+
+    /// Returns `true` if `self` contains all of the same values as `other`,
+    /// regardless of each set's indexed order, determined in parallel.
+    pub fn par_eq<S2>(&self, other: &IndexSet<T, S2>) -> bool
+    where
+        S2: BuildHasher + Sync,
+    {
+        self.len() == other.len() && self.par_is_subset(other)
+    }
+
+    /// Returns `true` if `self` has no elements in common with `other`,
+    /// determined in parallel.
+    pub fn par_is_disjoint<S2>(&self, other: &IndexSet<T, S2>) -> bool
+    where
+        S2: BuildHasher + Sync,
+    {
+        if self.len() <= other.len() {
+            self.par_iter().all(move |value| !other.contains(value))
+        } else {
+            other.par_iter().all(move |value| !self.contains(value))
+        }
+    }
+
+    /// Returns `true` if all elements of `other` are contained in `self`,
+    /// determined in parallel.
+    pub fn par_is_superset<S2>(&self, other: &IndexSet<T, S2>) -> bool
+    where
+        S2: BuildHasher + Sync,
+    {
+        other.par_is_subset(self)
+    }
+
+    /// Returns `true` if all elements of `self` are contained in `other`,
+    /// determined in parallel.
+    pub fn par_is_subset<S2>(&self, other: &IndexSet<T, S2>) -> bool
+    where
+        S2: BuildHasher + Sync,
+    {
+        self.len() <= other.len() && self.par_iter().all(move |value| other.contains(value))
+    }
+}
+
+/// A parallel iterator producing elements in the difference of `IndexSet`s.
+///
+/// This `struct` is created by the [`par_difference`] method on [`IndexSet`].
+/// See its documentation for more.
+///
+/// [`IndexSet`]: ../struct.IndexSet.html
+/// [`par_difference`]: ../struct.IndexSet.html#method.par_difference
+pub struct ParDifference<'a, T, S1, S2> {
+    set1: &'a IndexSet<T, S1>,
+    set2: &'a IndexSet<T, S2>,
+}
+
+impl<T, S1, S2> Clone for ParDifference<'_, T, S1, S2> {
+    fn clone(&self) -> Self {
+        ParDifference { ..*self }
+    }
+}
+
+impl<T, S1, S2> fmt::Debug for ParDifference<'_, T, S1, S2>
+where
+    T: fmt::Debug + Eq + Hash,
+    S1: BuildHasher,
+    S2: BuildHasher,
+{
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_list()
+            .entries(self.set1.difference(self.set2))
+            .finish()
+    }
+}
+
+impl<'a, T, S1, S2> ParallelIterator for ParDifference<'a, T, S1, S2>
+where
+    T: Hash + Eq + Sync,
+    S1: BuildHasher + Sync,
+    S2: BuildHasher + Sync,
+{
+    type Item = &'a T;
+
+    fn drive_unindexed<C>(self, consumer: C) -> C::Result
+    where
+        C: UnindexedConsumer<Self::Item>,
+    {
+        let Self { set1, set2 } = self;
+
+        set1.par_iter()
+            .filter(move |&item| !set2.contains(item))
+            .drive_unindexed(consumer)
+    }
+}
+
+/// A parallel iterator producing elements in the intersection of `IndexSet`s.
+///
+/// This `struct` is created by the [`par_intersection`] method on [`IndexSet`].
+/// See its documentation for more.
+///
+/// [`IndexSet`]: ../struct.IndexSet.html
+/// [`par_intersection`]: ../struct.IndexSet.html#method.par_intersection
+pub struct ParIntersection<'a, T, S1, S2> {
+    set1: &'a IndexSet<T, S1>,
+    set2: &'a IndexSet<T, S2>,
+}
+
+impl<T, S1, S2> Clone for ParIntersection<'_, T, S1, S2> {
+    fn clone(&self) -> Self {
+        ParIntersection { ..*self }
+    }
+}
+
+impl<T, S1, S2> fmt::Debug for ParIntersection<'_, T, S1, S2>
+where
+    T: fmt::Debug + Eq + Hash,
+    S1: BuildHasher,
+    S2: BuildHasher,
+{
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_list()
+            .entries(self.set1.intersection(self.set2))
+            .finish()
+    }
+}
+
+impl<'a, T, S1, S2> ParallelIterator for ParIntersection<'a, T, S1, S2>
+where
+    T: Hash + Eq + Sync,
+    S1: BuildHasher + Sync,
+    S2: BuildHasher + Sync,
+{
+    type Item = &'a T;
+
+    fn drive_unindexed<C>(self, consumer: C) -> C::Result
+    where
+        C: UnindexedConsumer<Self::Item>,
+    {
+        let Self { set1, set2 } = self;
+
+        set1.par_iter()
+            .filter(move |&item| set2.contains(item))
+            .drive_unindexed(consumer)
+    }
+}
+
+/// A parallel iterator producing elements in the symmetric difference of `IndexSet`s.
+///
+/// This `struct` is created by the [`par_symmetric_difference`] method on
+/// [`IndexSet`]. See its documentation for more.
+///
+/// [`IndexSet`]: ../struct.IndexSet.html
+/// [`par_symmetric_difference`]: ../struct.IndexSet.html#method.par_symmetric_difference
+pub struct ParSymmetricDifference<'a, T, S1, S2> {
+    set1: &'a IndexSet<T, S1>,
+    set2: &'a IndexSet<T, S2>,
+}
+
+impl<T, S1, S2> Clone for ParSymmetricDifference<'_, T, S1, S2> {
+    fn clone(&self) -> Self {
+        ParSymmetricDifference { ..*self }
+    }
+}
+
+impl<T, S1, S2> fmt::Debug for ParSymmetricDifference<'_, T, S1, S2>
+where
+    T: fmt::Debug + Eq + Hash,
+    S1: BuildHasher,
+    S2: BuildHasher,
+{
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_list()
+            .entries(self.set1.symmetric_difference(self.set2))
+            .finish()
+    }
+}
+
+impl<'a, T, S1, S2> ParallelIterator for ParSymmetricDifference<'a, T, S1, S2>
+where
+    T: Hash + Eq + Sync,
+    S1: BuildHasher + Sync,
+    S2: BuildHasher + Sync,
+{
+    type Item = &'a T;
+
+    fn drive_unindexed<C>(self, consumer: C) -> C::Result
+    where
+        C: UnindexedConsumer<Self::Item>,
+    {
+        let Self { set1, set2 } = self;
+
+        set1.par_difference(set2)
+            .chain(set2.par_difference(set1))
+            .drive_unindexed(consumer)
+    }
+}
+
+/// A parallel iterator producing elements in the union of `IndexSet`s.
+///
+/// This `struct` is created by the [`par_union`] method on [`IndexSet`].
+/// See its documentation for more.
+///
+/// [`IndexSet`]: ../struct.IndexSet.html
+/// [`par_union`]: ../struct.IndexSet.html#method.par_union
+pub struct ParUnion<'a, T, S1, S2> {
+    set1: &'a IndexSet<T, S1>,
+    set2: &'a IndexSet<T, S2>,
+}
+
+impl<T, S1, S2> Clone for ParUnion<'_, T, S1, S2> {
+    fn clone(&self) -> Self {
+        ParUnion { ..*self }
+    }
+}
+
+impl<T, S1, S2> fmt::Debug for ParUnion<'_, T, S1, S2>
+where
+    T: fmt::Debug + Eq + Hash,
+    S1: BuildHasher,
+    S2: BuildHasher,
+{
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_list().entries(self.set1.union(self.set2)).finish()
+    }
+}
+
+impl<'a, T, S1, S2> ParallelIterator for ParUnion<'a, T, S1, S2>
+where
+    T: Hash + Eq + Sync,
+    S1: BuildHasher + Sync,
+    S2: BuildHasher + Sync,
+{
+    type Item = &'a T;
+
+    fn drive_unindexed<C>(self, consumer: C) -> C::Result
+    where
+        C: UnindexedConsumer<Self::Item>,
+    {
+        let Self { set1, set2 } = self;
+
+        set1.par_iter()
+            .chain(set2.par_difference(set1))
+            .drive_unindexed(consumer)
+    }
+}
+
+/// Parallel sorting methods.
+///
+/// The following methods **require crate feature `"rayon"`**.
+impl<T, S> IndexSet<T, S>
+where
+    T: Hash + Eq + Send,
+    S: BuildHasher + Send,
+{
+    /// Sort the set’s values in parallel by their default ordering.
+    pub fn par_sort(&mut self)
+    where
+        T: Ord,
+    {
+        self.with_entries(|entries| {
+            entries.par_sort_by(|a, b| T::cmp(&a.key, &b.key));
+        });
+    }
+
+    /// Sort the set’s values in place and in parallel, using the comparison function `cmp`.
+    pub fn par_sort_by<F>(&mut self, cmp: F)
+    where
+        F: Fn(&T, &T) -> Ordering + Sync,
+    {
+        self.with_entries(|entries| {
+            entries.par_sort_by(move |a, b| cmp(&a.key, &b.key));
+        });
+    }
+
+    /// Sort the values of the set in parallel and return a by-value parallel iterator of
+    /// the values with the result.
+    pub fn par_sorted_by<F>(self, cmp: F) -> IntoParIter<T>
+    where
+        F: Fn(&T, &T) -> Ordering + Sync,
+    {
+        let mut entries = self.into_entries();
+        entries.par_sort_by(move |a, b| cmp(&a.key, &b.key));
+        IntoParIter { entries }
+    }
+
+    /// Sort the set's values in parallel by their default ordering.
+    pub fn par_sort_unstable(&mut self)
+    where
+        T: Ord,
+    {
+        self.with_entries(|entries| {
+            entries.par_sort_unstable_by(|a, b| T::cmp(&a.key, &b.key));
+        });
+    }
+
+    /// Sort the set’s values in place and in parallel, using the comparison function `cmp`.
+    pub fn par_sort_unstable_by<F>(&mut self, cmp: F)
+    where
+        F: Fn(&T, &T) -> Ordering + Sync,
+    {
+        self.with_entries(|entries| {
+            entries.par_sort_unstable_by(move |a, b| cmp(&a.key, &b.key));
+        });
+    }
+
+    /// Sort the values of the set in parallel and return a by-value parallel iterator of
+    /// the values with the result.
+    pub fn par_sorted_unstable_by<F>(self, cmp: F) -> IntoParIter<T>
+    where
+        F: Fn(&T, &T) -> Ordering + Sync,
+    {
+        let mut entries = self.into_entries();
+        entries.par_sort_unstable_by(move |a, b| cmp(&a.key, &b.key));
+        IntoParIter { entries }
+    }
+}
+
+/// Requires crate feature `"rayon"`.
+impl<T, S> FromParallelIterator<T> for IndexSet<T, S>
+where
+    T: Eq + Hash + Send,
+    S: BuildHasher + Default + Send,
+{
+    fn from_par_iter<I>(iter: I) -> Self
+    where
+        I: IntoParallelIterator<Item = T>,
+    {
+        let list = collect(iter);
+        let len = list.iter().map(Vec::len).sum();
+        let mut set = Self::with_capacity_and_hasher(len, S::default());
+        for vec in list {
+            set.extend(vec);
+        }
+        set
+    }
+}
+
+/// Requires crate feature `"rayon"`.
+impl<T, S> ParallelExtend<T> for IndexSet<T, S>
+where
+    T: Eq + Hash + Send,
+    S: BuildHasher + Send,
+{
+    fn par_extend<I>(&mut self, iter: I)
+    where
+        I: IntoParallelIterator<Item = T>,
+    {
+        for vec in collect(iter) {
+            self.extend(vec);
+        }
+    }
+}
+
+/// Requires crate feature `"rayon"`.
+impl<'a, T: 'a, S> ParallelExtend<&'a T> for IndexSet<T, S>
+where
+    T: Copy + Eq + Hash + Send + Sync,
+    S: BuildHasher + Send,
+{
+    fn par_extend<I>(&mut self, iter: I)
+    where
+        I: IntoParallelIterator<Item = &'a T>,
+    {
+        for vec in collect(iter) {
+            self.extend(vec);
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn insert_order() {
+        let insert = [0, 4, 2, 12, 8, 7, 11, 5, 3, 17, 19, 22, 23];
+        let mut set = IndexSet::new();
+
+        for &elt in &insert {
+            set.insert(elt);
+        }
+
+        assert_eq!(set.par_iter().count(), set.len());
+        assert_eq!(set.par_iter().count(), insert.len());
+        insert.par_iter().zip(&set).for_each(|(a, b)| {
+            assert_eq!(a, b);
+        });
+        (0..insert.len())
+            .into_par_iter()
+            .zip(&set)
+            .for_each(|(i, v)| {
+                assert_eq!(set.get_index(i).unwrap(), v);
+            });
+    }
+
+    #[test]
+    fn partial_eq_and_eq() {
+        let mut set_a = IndexSet::new();
+        set_a.insert(1);
+        set_a.insert(2);
+        let mut set_b = set_a.clone();
+        assert!(set_a.par_eq(&set_b));
+        set_b.swap_remove(&1);
+        assert!(!set_a.par_eq(&set_b));
+        set_b.insert(3);
+        assert!(!set_a.par_eq(&set_b));
+
+        let set_c: IndexSet<_> = set_b.into_par_iter().collect();
+        assert!(!set_a.par_eq(&set_c));
+        assert!(!set_c.par_eq(&set_a));
+    }
+
+    #[test]
+    fn extend() {
+        let mut set = IndexSet::new();
+        set.par_extend(vec![&1, &2, &3, &4]);
+        set.par_extend(vec![5, 6]);
+        assert_eq!(
+            set.into_par_iter().collect::<Vec<_>>(),
+            vec![1, 2, 3, 4, 5, 6]
+        );
+    }
+
+    #[test]
+    fn comparisons() {
+        let set_a: IndexSet<_> = (0..3).collect();
+        let set_b: IndexSet<_> = (3..6).collect();
+        let set_c: IndexSet<_> = (0..6).collect();
+        let set_d: IndexSet<_> = (3..9).collect();
+
+        assert!(!set_a.par_is_disjoint(&set_a));
+        assert!(set_a.par_is_subset(&set_a));
+        assert!(set_a.par_is_superset(&set_a));
+
+        assert!(set_a.par_is_disjoint(&set_b));
+        assert!(set_b.par_is_disjoint(&set_a));
+        assert!(!set_a.par_is_subset(&set_b));
+        assert!(!set_b.par_is_subset(&set_a));
+        assert!(!set_a.par_is_superset(&set_b));
+        assert!(!set_b.par_is_superset(&set_a));
+
+        assert!(!set_a.par_is_disjoint(&set_c));
+        assert!(!set_c.par_is_disjoint(&set_a));
+        assert!(set_a.par_is_subset(&set_c));
+        assert!(!set_c.par_is_subset(&set_a));
+        assert!(!set_a.par_is_superset(&set_c));
+        assert!(set_c.par_is_superset(&set_a));
+
+        assert!(!set_c.par_is_disjoint(&set_d));
+        assert!(!set_d.par_is_disjoint(&set_c));
+        assert!(!set_c.par_is_subset(&set_d));
+        assert!(!set_d.par_is_subset(&set_c));
+        assert!(!set_c.par_is_superset(&set_d));
+        assert!(!set_d.par_is_superset(&set_c));
+    }
+
+    #[test]
+    fn iter_comparisons() {
+        use std::iter::empty;
+
+        fn check<'a, I1, I2>(iter1: I1, iter2: I2)
+        where
+            I1: ParallelIterator<Item = &'a i32>,
+            I2: Iterator<Item = i32>,
+        {
+            let v1: Vec<_> = iter1.copied().collect();
+            let v2: Vec<_> = iter2.collect();
+            assert_eq!(v1, v2);
+        }
+
+        let set_a: IndexSet<_> = (0..3).collect();
+        let set_b: IndexSet<_> = (3..6).collect();
+        let set_c: IndexSet<_> = (0..6).collect();
+        let set_d: IndexSet<_> = (3..9).rev().collect();
+
+        check(set_a.par_difference(&set_a), empty());
+        check(set_a.par_symmetric_difference(&set_a), empty());
+        check(set_a.par_intersection(&set_a), 0..3);
+        check(set_a.par_union(&set_a), 0..3);
+
+        check(set_a.par_difference(&set_b), 0..3);
+        check(set_b.par_difference(&set_a), 3..6);
+        check(set_a.par_symmetric_difference(&set_b), 0..6);
+        check(set_b.par_symmetric_difference(&set_a), (3..6).chain(0..3));
+        check(set_a.par_intersection(&set_b), empty());
+        check(set_b.par_intersection(&set_a), empty());
+        check(set_a.par_union(&set_b), 0..6);
+        check(set_b.par_union(&set_a), (3..6).chain(0..3));
+
+        check(set_a.par_difference(&set_c), empty());
+        check(set_c.par_difference(&set_a), 3..6);
+        check(set_a.par_symmetric_difference(&set_c), 3..6);
+        check(set_c.par_symmetric_difference(&set_a), 3..6);
+        check(set_a.par_intersection(&set_c), 0..3);
+        check(set_c.par_intersection(&set_a), 0..3);
+        check(set_a.par_union(&set_c), 0..6);
+        check(set_c.par_union(&set_a), 0..6);
+
+        check(set_c.par_difference(&set_d), 0..3);
+        check(set_d.par_difference(&set_c), (6..9).rev());
+        check(
+            set_c.par_symmetric_difference(&set_d),
+            (0..3).chain((6..9).rev()),
+        );
+        check(
+            set_d.par_symmetric_difference(&set_c),
+            (6..9).rev().chain(0..3),
+        );
+        check(set_c.par_intersection(&set_d), 3..6);
+        check(set_d.par_intersection(&set_c), (3..6).rev());
+        check(set_c.par_union(&set_d), (0..6).chain((6..9).rev()));
+        check(set_d.par_union(&set_c), (3..9).rev().chain(0..3));
+    }
+}