Merging upstream version 1.67.1+dfsg1.

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

17 files changed, 624 insertions, 79 deletions

diff --git a/vendor/rayon/src/iter/chunks.rs b/vendor/rayon/src/iter/chunks.rs
index be5f84cc7..ec48278d0 100644
--- a/vendor/rayon/src/iter/chunks.rs
+++ b/vendor/rayon/src/iter/chunks.rs
@@ -90,38 +90,46 @@ where
             where
                 P: Producer<Item = T>,
             {
-                self.callback.callback(ChunkProducer {
-                    chunk_size: self.size,
-                    len: self.len,
-                    base,
-                })
+                let producer = ChunkProducer::new(self.size, self.len, base, Vec::from_iter);
+                self.callback.callback(producer)
             }
         }
     }
 }
 
-struct ChunkProducer<P>
-where
-    P: Producer,
-{
+pub(super) struct ChunkProducer<P, F> {
     chunk_size: usize,
     len: usize,
     base: P,
+    map: F,
 }
 
-impl<P> Producer for ChunkProducer<P>
+impl<P, F> ChunkProducer<P, F> {
+    pub(super) fn new(chunk_size: usize, len: usize, base: P, map: F) -> Self {
+        Self {
+            chunk_size,
+            len,
+            base,
+            map,
+        }
+    }
+}
+
+impl<P, F, T> Producer for ChunkProducer<P, F>
 where
     P: Producer,
+    F: Fn(P::IntoIter) -> T + Send + Clone,
 {
-    type Item = Vec<P::Item>;
-    type IntoIter = ChunkSeq<P>;
+    type Item = T;
+    type IntoIter = std::iter::Map<ChunkSeq<P>, F>;
 
     fn into_iter(self) -> Self::IntoIter {
-        ChunkSeq {
+        let chunks = ChunkSeq {
             chunk_size: self.chunk_size,
             len: self.len,
             inner: if self.len > 0 { Some(self.base) } else { None },
-        }
+        };
+        chunks.map(self.map)
     }
 
     fn split_at(self, index: usize) -> (Self, Self) {
@@ -132,11 +140,13 @@ where
                 chunk_size: self.chunk_size,
                 len: elem_index,
                 base: left,
+                map: self.map.clone(),
             },
             ChunkProducer {
                 chunk_size: self.chunk_size,
                 len: self.len - elem_index,
                 base: right,
+                map: self.map,
             },
         )
     }
@@ -150,7 +160,7 @@ where
     }
 }
 
-struct ChunkSeq<P> {
+pub(super) struct ChunkSeq<P> {
     chunk_size: usize,
     len: usize,
     inner: Option<P>,
@@ -160,7 +170,7 @@ impl<P> Iterator for ChunkSeq<P>
 where
     P: Producer,
 {
-    type Item = Vec<P::Item>;
+    type Item = P::IntoIter;
 
     fn next(&mut self) -> Option<Self::Item> {
         let producer = self.inner.take()?;
@@ -168,11 +178,11 @@ where
             let (left, right) = producer.split_at(self.chunk_size);
             self.inner = Some(right);
             self.len -= self.chunk_size;
-            Some(left.into_iter().collect())
+            Some(left.into_iter())
         } else {
             debug_assert!(self.len > 0);
             self.len = 0;
-            Some(producer.into_iter().collect())
+            Some(producer.into_iter())
         }
     }
 
@@ -206,11 +216,11 @@ where
             let (left, right) = producer.split_at(self.len - size);
             self.inner = Some(left);
             self.len -= size;
-            Some(right.into_iter().collect())
+            Some(right.into_iter())
         } else {
             debug_assert!(self.len > 0);
             self.len = 0;
-            Some(producer.into_iter().collect())
+            Some(producer.into_iter())
         }
     }
 }
diff --git a/vendor/rayon/src/iter/filter.rs b/vendor/rayon/src/iter/filter.rs
index 38627f7c0..e1b74ba52 100644
--- a/vendor/rayon/src/iter/filter.rs
+++ b/vendor/rayon/src/iter/filter.rs
@@ -97,7 +97,7 @@ where
     P: Fn(&T) -> bool + Sync,
 {
     fn split_off_left(&self) -> Self {
-        FilterConsumer::new(self.base.split_off_left(), &self.filter_op)
+        FilterConsumer::new(self.base.split_off_left(), self.filter_op)
     }
 
     fn to_reducer(&self) -> Self::Reducer {
diff --git a/vendor/rayon/src/iter/filter_map.rs b/vendor/rayon/src/iter/filter_map.rs
index f19c38563..db1c7e3f0 100644
--- a/vendor/rayon/src/iter/filter_map.rs
+++ b/vendor/rayon/src/iter/filter_map.rs
@@ -98,7 +98,7 @@ where
     P: Fn(T) -> Option<U> + Sync + 'p,
 {
     fn split_off_left(&self) -> Self {
-        FilterMapConsumer::new(self.base.split_off_left(), &self.filter_op)
+        FilterMapConsumer::new(self.base.split_off_left(), self.filter_op)
     }
 
     fn to_reducer(&self) -> Self::Reducer {
diff --git a/vendor/rayon/src/iter/find.rs b/vendor/rayon/src/iter/find.rs
index 971db2b3c..b16ee8446 100644
--- a/vendor/rayon/src/iter/find.rs
+++ b/vendor/rayon/src/iter/find.rs
@@ -94,7 +94,7 @@ where
         self.item = iter
             .into_iter()
             // stop iterating if another thread has found something
-            .take_while(not_full(&self.found))
+            .take_while(not_full(self.found))
             .find(self.find_op);
         if self.item.is_some() {
             self.found.store(true, Ordering::Relaxed)
diff --git a/vendor/rayon/src/iter/fold_chunks.rs b/vendor/rayon/src/iter/fold_chunks.rs
new file mode 100644
index 000000000..185fb1a65
--- /dev/null
+++ b/vendor/rayon/src/iter/fold_chunks.rs
@@ -0,0 +1,236 @@
+use std::fmt::{self, Debug};
+
+use super::chunks::ChunkProducer;
+use super::plumbing::*;
+use super::*;
+use crate::math::div_round_up;
+
+/// `FoldChunks` is an iterator that groups elements of an underlying iterator and applies a
+/// function over them, producing a single value for each group.
+///
+/// This struct is created by the [`fold_chunks()`] method on [`IndexedParallelIterator`]
+///
+/// [`fold_chunks()`]: trait.IndexedParallelIterator.html#method.fold_chunks
+/// [`IndexedParallelIterator`]: trait.IndexedParallelIterator.html
+#[must_use = "iterator adaptors are lazy and do nothing unless consumed"]
+#[derive(Clone)]
+pub struct FoldChunks<I, ID, F>
+where
+    I: IndexedParallelIterator,
+{
+    base: I,
+    chunk_size: usize,
+    fold_op: F,
+    identity: ID,
+}
+
+impl<I: IndexedParallelIterator + Debug, ID, F> Debug for FoldChunks<I, ID, F> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("Fold")
+            .field("base", &self.base)
+            .field("chunk_size", &self.chunk_size)
+            .finish()
+    }
+}
+
+impl<I, ID, U, F> FoldChunks<I, ID, F>
+where
+    I: IndexedParallelIterator,
+    ID: Fn() -> U + Send + Sync,
+    F: Fn(U, I::Item) -> U + Send + Sync,
+    U: Send,
+{
+    /// Creates a new `FoldChunks` iterator
+    pub(super) fn new(base: I, chunk_size: usize, identity: ID, fold_op: F) -> Self {
+        FoldChunks {
+            base,
+            chunk_size,
+            identity,
+            fold_op,
+        }
+    }
+}
+
+impl<I, ID, U, F> ParallelIterator for FoldChunks<I, ID, F>
+where
+    I: IndexedParallelIterator,
+    ID: Fn() -> U + Send + Sync,
+    F: Fn(U, I::Item) -> U + Send + Sync,
+    U: Send,
+{
+    type Item = U;
+
+    fn drive_unindexed<C>(self, consumer: C) -> C::Result
+    where
+        C: Consumer<U>,
+    {
+        bridge(self, consumer)
+    }
+
+    fn opt_len(&self) -> Option<usize> {
+        Some(self.len())
+    }
+}
+
+impl<I, ID, U, F> IndexedParallelIterator for FoldChunks<I, ID, F>
+where
+    I: IndexedParallelIterator,
+    ID: Fn() -> U + Send + Sync,
+    F: Fn(U, I::Item) -> U + Send + Sync,
+    U: Send,
+{
+    fn len(&self) -> usize {
+        div_round_up(self.base.len(), self.chunk_size)
+    }
+
+    fn drive<C>(self, consumer: C) -> C::Result
+    where
+        C: Consumer<Self::Item>,
+    {
+        bridge(self, consumer)
+    }
+
+    fn with_producer<CB>(self, callback: CB) -> CB::Output
+    where
+        CB: ProducerCallback<Self::Item>,
+    {
+        let len = self.base.len();
+        return self.base.with_producer(Callback {
+            chunk_size: self.chunk_size,
+            len,
+            identity: self.identity,
+            fold_op: self.fold_op,
+            callback,
+        });
+
+        struct Callback<CB, ID, F> {
+            chunk_size: usize,
+            len: usize,
+            identity: ID,
+            fold_op: F,
+            callback: CB,
+        }
+
+        impl<T, CB, ID, U, F> ProducerCallback<T> for Callback<CB, ID, F>
+        where
+            CB: ProducerCallback<U>,
+            ID: Fn() -> U + Send + Sync,
+            F: Fn(U, T) -> U + Send + Sync,
+        {
+            type Output = CB::Output;
+
+            fn callback<P>(self, base: P) -> CB::Output
+            where
+                P: Producer<Item = T>,
+            {
+                let identity = &self.identity;
+                let fold_op = &self.fold_op;
+                let fold_iter = move |iter: P::IntoIter| iter.fold(identity(), fold_op);
+                let producer = ChunkProducer::new(self.chunk_size, self.len, base, fold_iter);
+                self.callback.callback(producer)
+            }
+        }
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+    use std::ops::Add;
+
+    #[test]
+    fn check_fold_chunks() {
+        let words = "bishbashbosh!"
+            .chars()
+            .collect::<Vec<_>>()
+            .into_par_iter()
+            .fold_chunks(4, String::new, |mut s, c| {
+                s.push(c);
+                s
+            })
+            .collect::<Vec<_>>();
+
+        assert_eq!(words, vec!["bish", "bash", "bosh", "!"]);
+    }
+
+    // 'closure' values for tests below
+    fn id() -> i32 {
+        0
+    }
+    fn sum<T, U>(x: T, y: U) -> T
+    where
+        T: Add<U, Output = T>,
+    {
+        x + y
+    }
+
+    #[test]
+    #[should_panic(expected = "chunk_size must not be zero")]
+    fn check_fold_chunks_zero_size() {
+        let _: Vec<i32> = vec![1, 2, 3]
+            .into_par_iter()
+            .fold_chunks(0, id, sum)
+            .collect();
+    }
+
+    #[test]
+    fn check_fold_chunks_even_size() {
+        assert_eq!(
+            vec![1 + 2 + 3, 4 + 5 + 6, 7 + 8 + 9],
+            (1..10)
+                .into_par_iter()
+                .fold_chunks(3, id, sum)
+                .collect::<Vec<i32>>()
+        );
+    }
+
+    #[test]
+    fn check_fold_chunks_empty() {
+        let v: Vec<i32> = vec![];
+        let expected: Vec<i32> = vec![];
+        assert_eq!(
+            expected,
+            v.into_par_iter()
+                .fold_chunks(2, id, sum)
+                .collect::<Vec<i32>>()
+        );
+    }
+
+    #[test]
+    fn check_fold_chunks_len() {
+        assert_eq!(4, (0..8).into_par_iter().fold_chunks(2, id, sum).len());
+        assert_eq!(3, (0..9).into_par_iter().fold_chunks(3, id, sum).len());
+        assert_eq!(3, (0..8).into_par_iter().fold_chunks(3, id, sum).len());
+        assert_eq!(1, (&[1]).par_iter().fold_chunks(3, id, sum).len());
+        assert_eq!(0, (0..0).into_par_iter().fold_chunks(3, id, sum).len());
+    }
+
+    #[test]
+    fn check_fold_chunks_uneven() {
+        let cases: Vec<(Vec<u32>, usize, Vec<u32>)> = vec![
+            ((0..5).collect(), 3, vec![0 + 1 + 2, 3 + 4]),
+            (vec![1], 5, vec![1]),
+            ((0..4).collect(), 3, vec![0 + 1 + 2, 3]),
+        ];
+
+        for (i, (v, n, expected)) in cases.into_iter().enumerate() {
+            let mut res: Vec<u32> = vec![];
+            v.par_iter()
+                .fold_chunks(n, || 0, sum)
+                .collect_into_vec(&mut res);
+            assert_eq!(expected, res, "Case {} failed", i);
+
+            res.truncate(0);
+            v.into_par_iter()
+                .fold_chunks(n, || 0, sum)
+                .rev()
+                .collect_into_vec(&mut res);
+            assert_eq!(
+                expected.into_iter().rev().collect::<Vec<u32>>(),
+                res,
+                "Case {} reversed failed",
+                i
+            );
+        }
+    }
+}
diff --git a/vendor/rayon/src/iter/fold_chunks_with.rs b/vendor/rayon/src/iter/fold_chunks_with.rs
new file mode 100644
index 000000000..af120aec4
--- /dev/null
+++ b/vendor/rayon/src/iter/fold_chunks_with.rs
@@ -0,0 +1,231 @@
+use std::fmt::{self, Debug};
+
+use super::chunks::ChunkProducer;
+use super::plumbing::*;
+use super::*;
+use crate::math::div_round_up;
+
+/// `FoldChunksWith` is an iterator that groups elements of an underlying iterator and applies a
+/// function over them, producing a single value for each group.
+///
+/// This struct is created by the [`fold_chunks_with()`] method on [`IndexedParallelIterator`]
+///
+/// [`fold_chunks_with()`]: trait.IndexedParallelIterator.html#method.fold_chunks
+/// [`IndexedParallelIterator`]: trait.IndexedParallelIterator.html
+#[must_use = "iterator adaptors are lazy and do nothing unless consumed"]
+#[derive(Clone)]
+pub struct FoldChunksWith<I, U, F>
+where
+    I: IndexedParallelIterator,
+{
+    base: I,
+    chunk_size: usize,
+    item: U,
+    fold_op: F,
+}
+
+impl<I: IndexedParallelIterator + Debug, U: Debug, F> Debug for FoldChunksWith<I, U, F> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("Fold")
+            .field("base", &self.base)
+            .field("chunk_size", &self.chunk_size)
+            .field("item", &self.item)
+            .finish()
+    }
+}
+
+impl<I, U, F> FoldChunksWith<I, U, F>
+where
+    I: IndexedParallelIterator,
+    U: Send + Clone,
+    F: Fn(U, I::Item) -> U + Send + Sync,
+{
+    /// Creates a new `FoldChunksWith` iterator
+    pub(super) fn new(base: I, chunk_size: usize, item: U, fold_op: F) -> Self {
+        FoldChunksWith {
+            base,
+            chunk_size,
+            item,
+            fold_op,
+        }
+    }
+}
+
+impl<I, U, F> ParallelIterator for FoldChunksWith<I, U, F>
+where
+    I: IndexedParallelIterator,
+    U: Send + Clone,
+    F: Fn(U, I::Item) -> U + Send + Sync,
+{
+    type Item = U;
+
+    fn drive_unindexed<C>(self, consumer: C) -> C::Result
+    where
+        C: Consumer<U>,
+    {
+        bridge(self, consumer)
+    }
+
+    fn opt_len(&self) -> Option<usize> {
+        Some(self.len())
+    }
+}
+
+impl<I, U, F> IndexedParallelIterator for FoldChunksWith<I, U, F>
+where
+    I: IndexedParallelIterator,
+    U: Send + Clone,
+    F: Fn(U, I::Item) -> U + Send + Sync,
+{
+    fn len(&self) -> usize {
+        div_round_up(self.base.len(), self.chunk_size)
+    }
+
+    fn drive<C>(self, consumer: C) -> C::Result
+    where
+        C: Consumer<Self::Item>,
+    {
+        bridge(self, consumer)
+    }
+
+    fn with_producer<CB>(self, callback: CB) -> CB::Output
+    where
+        CB: ProducerCallback<Self::Item>,
+    {
+        let len = self.base.len();
+        return self.base.with_producer(Callback {
+            chunk_size: self.chunk_size,
+            len,
+            item: self.item,
+            fold_op: self.fold_op,
+            callback,
+        });
+
+        struct Callback<CB, T, F> {
+            chunk_size: usize,
+            len: usize,
+            item: T,
+            fold_op: F,
+            callback: CB,
+        }
+
+        impl<T, U, F, CB> ProducerCallback<T> for Callback<CB, U, F>
+        where
+            CB: ProducerCallback<U>,
+            U: Send + Clone,
+            F: Fn(U, T) -> U + Send + Sync,
+        {
+            type Output = CB::Output;
+
+            fn callback<P>(self, base: P) -> CB::Output
+            where
+                P: Producer<Item = T>,
+            {
+                let item = self.item;
+                let fold_op = &self.fold_op;
+                let fold_iter = move |iter: P::IntoIter| iter.fold(item.clone(), fold_op);
+                let producer = ChunkProducer::new(self.chunk_size, self.len, base, fold_iter);
+                self.callback.callback(producer)
+            }
+        }
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+    use std::ops::Add;
+
+    #[test]
+    fn check_fold_chunks_with() {
+        let words = "bishbashbosh!"
+            .chars()
+            .collect::<Vec<_>>()
+            .into_par_iter()
+            .fold_chunks_with(4, String::new(), |mut s, c| {
+                s.push(c);
+                s
+            })
+            .collect::<Vec<_>>();
+
+        assert_eq!(words, vec!["bish", "bash", "bosh", "!"]);
+    }
+
+    // 'closure' value for tests below
+    fn sum<T, U>(x: T, y: U) -> T
+    where
+        T: Add<U, Output = T>,
+    {
+        x + y
+    }
+
+    #[test]
+    #[should_panic(expected = "chunk_size must not be zero")]
+    fn check_fold_chunks_zero_size() {
+        let _: Vec<i32> = vec![1, 2, 3]
+            .into_par_iter()
+            .fold_chunks_with(0, 0, sum)
+            .collect();
+    }
+
+    #[test]
+    fn check_fold_chunks_even_size() {
+        assert_eq!(
+            vec![1 + 2 + 3, 4 + 5 + 6, 7 + 8 + 9],
+            (1..10)
+                .into_par_iter()
+                .fold_chunks_with(3, 0, sum)
+                .collect::<Vec<i32>>()
+        );
+    }
+
+    #[test]
+    fn check_fold_chunks_with_empty() {
+        let v: Vec<i32> = vec![];
+        let expected: Vec<i32> = vec![];
+        assert_eq!(
+            expected,
+            v.into_par_iter()
+                .fold_chunks_with(2, 0, sum)
+                .collect::<Vec<i32>>()
+        );
+    }
+
+    #[test]
+    fn check_fold_chunks_len() {
+        assert_eq!(4, (0..8).into_par_iter().fold_chunks_with(2, 0, sum).len());
+        assert_eq!(3, (0..9).into_par_iter().fold_chunks_with(3, 0, sum).len());
+        assert_eq!(3, (0..8).into_par_iter().fold_chunks_with(3, 0, sum).len());
+        assert_eq!(1, (&[1]).par_iter().fold_chunks_with(3, 0, sum).len());
+        assert_eq!(0, (0..0).into_par_iter().fold_chunks_with(3, 0, sum).len());
+    }
+
+    #[test]
+    fn check_fold_chunks_uneven() {
+        let cases: Vec<(Vec<u32>, usize, Vec<u32>)> = vec![
+            ((0..5).collect(), 3, vec![0 + 1 + 2, 3 + 4]),
+            (vec![1], 5, vec![1]),
+            ((0..4).collect(), 3, vec![0 + 1 + 2, 3]),
+        ];
+
+        for (i, (v, n, expected)) in cases.into_iter().enumerate() {
+            let mut res: Vec<u32> = vec![];
+            v.par_iter()
+                .fold_chunks_with(n, 0, sum)
+                .collect_into_vec(&mut res);
+            assert_eq!(expected, res, "Case {} failed", i);
+
+            res.truncate(0);
+            v.into_par_iter()
+                .fold_chunks_with(n, 0, sum)
+                .rev()
+                .collect_into_vec(&mut res);
+            assert_eq!(
+                expected.into_iter().rev().collect::<Vec<u32>>(),
+                res,
+                "Case {} reversed failed",
+                i
+            );
+        }
+    }
+}
diff --git a/vendor/rayon/src/iter/inspect.rs b/vendor/rayon/src/iter/inspect.rs
index 9b1cd094d..c50ca022d 100644
--- a/vendor/rayon/src/iter/inspect.rs
+++ b/vendor/rayon/src/iter/inspect.rs
@@ -209,7 +209,7 @@ where
     F: Fn(&T) + Sync,
 {
     fn split_off_left(&self) -> Self {
-        InspectConsumer::new(self.base.split_off_left(), &self.inspect_op)
+        InspectConsumer::new(self.base.split_off_left(), self.inspect_op)
     }
 
     fn to_reducer(&self) -> Self::Reducer {
diff --git a/vendor/rayon/src/iter/interleave.rs b/vendor/rayon/src/iter/interleave.rs
index b5d43d53d..3cacc49f9 100644
--- a/vendor/rayon/src/iter/interleave.rs
+++ b/vendor/rayon/src/iter/interleave.rs
@@ -310,16 +310,16 @@ where
 {
     #[inline]
     fn next_back(&mut self) -> Option<I::Item> {
-        if self.i.len() == self.j.len() {
-            if self.i_next {
-                self.i.next_back()
-            } else {
-                self.j.next_back()
+        match self.i.len().cmp(&self.j.len()) {
+            Ordering::Less => self.j.next_back(),
+            Ordering::Equal => {
+                if self.i_next {
+                    self.i.next_back()
+                } else {
+                    self.j.next_back()
+                }
             }
-        } else if self.i.len() < self.j.len() {
-            self.j.next_back()
-        } else {
-            self.i.next_back()
+            Ordering::Greater => self.i.next_back(),
         }
     }
 }
diff --git a/vendor/rayon/src/iter/map.rs b/vendor/rayon/src/iter/map.rs
index f2a35ff8c..da14d4082 100644
--- a/vendor/rayon/src/iter/map.rs
+++ b/vendor/rayon/src/iter/map.rs
@@ -213,7 +213,7 @@ where
     R: Send,
 {
     fn split_off_left(&self) -> Self {
-        MapConsumer::new(self.base.split_off_left(), &self.map_op)
+        MapConsumer::new(self.base.split_off_left(), self.map_op)
     }
 
     fn to_reducer(&self) -> Self::Reducer {
diff --git a/vendor/rayon/src/iter/mod.rs b/vendor/rayon/src/iter/mod.rs
index 89e96fcef..98c93267f 100644
--- a/vendor/rayon/src/iter/mod.rs
+++ b/vendor/rayon/src/iter/mod.rs
@@ -119,6 +119,8 @@ mod flat_map_iter;
 mod flatten;
 mod flatten_iter;
 mod fold;
+mod fold_chunks;
+mod fold_chunks_with;
 mod for_each;
 mod from_par_iter;
 mod inspect;
@@ -140,6 +142,7 @@ mod repeat;
 mod rev;
 mod skip;
 mod splitter;
+mod step_by;
 mod sum;
 mod take;
 mod try_fold;
@@ -165,6 +168,8 @@ pub use self::{
     flatten::Flatten,
     flatten_iter::FlattenIter,
     fold::{Fold, FoldWith},
+    fold_chunks::FoldChunks,
+    fold_chunks_with::FoldChunksWith,
     inspect::Inspect,
     interleave::Interleave,
     interleave_shortest::InterleaveShortest,
@@ -181,6 +186,7 @@ pub use self::{
     rev::Rev,
     skip::Skip,
     splitter::{split, Split},
+    step_by::StepBy,
     take::Take,
     try_fold::{TryFold, TryFoldWith},
     update::Update,
@@ -189,10 +195,6 @@ pub use self::{
     zip_eq::ZipEq,
 };
 
-mod step_by;
-#[cfg(has_step_by_rev)]
-pub use self::step_by::StepBy;
-
 /// `IntoParallelIterator` implements the conversion to a [`ParallelIterator`].
 ///
 /// By implementing `IntoParallelIterator` for a type, you define how it will
@@ -1124,7 +1126,7 @@ pub trait ParallelIterator: Sized + Send {
     /// multiple sums. The number of results is nondeterministic, as
     /// is the point where the breaks occur.
     ///
-    /// So if did the same parallel fold (`fold(0, |a,b| a+b)`) on
+    /// So if we did the same parallel fold (`fold(0, |a,b| a+b)`) on
     /// our example list, we might wind up with a sequence of two numbers,
     /// like so:
     ///
@@ -2241,6 +2243,8 @@ impl<T: ParallelIterator> IntoParallelIterator for T {
 /// those points.
 ///
 /// **Note:** Not implemented for `u64`, `i64`, `u128`, or `i128` ranges
+// Waiting for `ExactSizeIterator::is_empty` to be stabilized. See rust-lang/rust#35428
+#[allow(clippy::len_without_is_empty)]
 pub trait IndexedParallelIterator: ParallelIterator {
     /// Collects the results of the iterator into the specified
     /// vector. The vector is always truncated before execution
@@ -2339,13 +2343,18 @@ pub trait IndexedParallelIterator: ParallelIterator {
     /// // we should never get here
     /// assert_eq!(1, zipped.len());
     /// ```
+    #[track_caller]
     fn zip_eq<Z>(self, zip_op: Z) -> ZipEq<Self, Z::Iter>
     where
         Z: IntoParallelIterator,
         Z::Iter: IndexedParallelIterator,
     {
         let zip_op_iter = zip_op.into_par_iter();
-        assert_eq!(self.len(), zip_op_iter.len());
+        assert_eq!(
+            self.len(),
+            zip_op_iter.len(),
+            "iterators must have the same length"
+        );
         ZipEq::new(self, zip_op_iter)
     }
 
@@ -2415,6 +2424,89 @@ pub trait IndexedParallelIterator: ParallelIterator {
         Chunks::new(self, chunk_size)
     }
 
+    /// Splits an iterator into fixed-size chunks, performing a sequential [`fold()`] on
+    /// each chunk.
+    ///
+    /// Returns an iterator that produces a folded result for each chunk of items
+    /// produced by this iterator.
+    ///
+    /// This works essentially like:
+    ///
+    /// ```text
+    /// iter.chunks(chunk_size)
+    ///     .map(|chunk|
+    ///         chunk.into_iter()
+    ///             .fold(identity, fold_op)
+    ///     )
+    /// ```
+    ///
+    /// except there is no per-chunk allocation overhead.
+    ///
+    /// [`fold()`]: std::iter::Iterator#method.fold
+    ///
+    /// **Panics** if `chunk_size` is 0.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use rayon::prelude::*;
+    /// let nums = vec![1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
+    /// let chunk_sums = nums.into_par_iter().fold_chunks(2, || 0, |a, n| a + n).collect::<Vec<_>>();
+    /// assert_eq!(chunk_sums, vec![3, 7, 11, 15, 19]);
+    /// ```
+    #[track_caller]
+    fn fold_chunks<T, ID, F>(
+        self,
+        chunk_size: usize,
+        identity: ID,
+        fold_op: F,
+    ) -> FoldChunks<Self, ID, F>
+    where
+        ID: Fn() -> T + Send + Sync,
+        F: Fn(T, Self::Item) -> T + Send + Sync,
+        T: Send,
+    {
+        assert!(chunk_size != 0, "chunk_size must not be zero");
+        FoldChunks::new(self, chunk_size, identity, fold_op)
+    }
+
+    /// Splits an iterator into fixed-size chunks, performing a sequential [`fold()`] on
+    /// each chunk.
+    ///
+    /// Returns an iterator that produces a folded result for each chunk of items
+    /// produced by this iterator.
+    ///
+    /// This works essentially like `fold_chunks(chunk_size, || init.clone(), fold_op)`,
+    /// except it doesn't require the `init` type to be `Sync`, nor any other form of
+    /// added synchronization.
+    ///
+    /// [`fold()`]: std::iter::Iterator#method.fold
+    ///
+    /// **Panics** if `chunk_size` is 0.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use rayon::prelude::*;
+    /// let nums = vec![1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
+    /// let chunk_sums = nums.into_par_iter().fold_chunks_with(2, 0, |a, n| a + n).collect::<Vec<_>>();
+    /// assert_eq!(chunk_sums, vec![3, 7, 11, 15, 19]);
+    /// ```
+    #[track_caller]
+    fn fold_chunks_with<T, F>(
+        self,
+        chunk_size: usize,
+        init: T,
+        fold_op: F,
+    ) -> FoldChunksWith<Self, T, F>
+    where
+        T: Send + Clone,
+        F: Fn(T, Self::Item) -> T + Send + Sync,
+    {
+        assert!(chunk_size != 0, "chunk_size must not be zero");
+        FoldChunksWith::new(self, chunk_size, init, fold_op)
+    }
+
     /// Lexicographically compares the elements of this `ParallelIterator` with those of
     /// another.
     ///
@@ -2601,11 +2693,6 @@ pub trait IndexedParallelIterator: ParallelIterator {
     ///
     /// assert_eq!(result, [3, 6, 9])
     /// ```
-    ///
-    /// # Compatibility
-    ///
-    /// This method is only available on Rust 1.38 or greater.
-    #[cfg(has_step_by_rev)]
     fn step_by(self, step: usize) -> StepBy<Self> {
         StepBy::new(self, step)
     }
@@ -3146,20 +3233,9 @@ pub trait ParallelDrainRange<Idx = usize> {
 /// stable clone of the standard library's `Try` trait, as yet unstable.
 mod private {
     use std::convert::Infallible;
+    use std::ops::ControlFlow::{self, Break, Continue};
     use std::task::Poll;
 
-    #[cfg(has_control_flow)]
-    pub(crate) use std::ops::ControlFlow;
-
-    #[cfg(not(has_control_flow))]
-    #[allow(missing_debug_implementations)]
-    pub enum ControlFlow<B, C = ()> {
-        Continue(C),
-        Break(B),
-    }
-
-    use self::ControlFlow::{Break, Continue};
-
     /// Clone of `std::ops::Try`.
     ///
     /// Implementing this trait is not permitted outside of `rayon`.
@@ -3176,7 +3252,6 @@ mod private {
         fn branch(self) -> ControlFlow<Self::Residual, Self::Output>;
     }
 
-    #[cfg(has_control_flow)]
     impl<B, C> Try for ControlFlow<B, C> {
         private_impl! {}
 
diff --git a/vendor/rayon/src/iter/plumbing/README.md b/vendor/rayon/src/iter/plumbing/README.md
index cd94eae30..dbee36ba0 100644
--- a/vendor/rayon/src/iter/plumbing/README.md
+++ b/vendor/rayon/src/iter/plumbing/README.md
@@ -124,7 +124,7 @@ implement `IndexedParallelIterator`.
 
 The `bridge` function will then connect the consumer, which is
 handling the `flat_map` and `for_each`, with the producer, which is
-handling the `zip` and its preecessors. It will split down until the
+handling the `zip` and its predecessors. It will split down until the
 chunks seem reasonably small, then pull items from the producer and
 feed them to the consumer.
 
diff --git a/vendor/rayon/src/iter/step_by.rs b/vendor/rayon/src/iter/step_by.rs
index 863de3cf0..94b8334e8 100644
--- a/vendor/rayon/src/iter/step_by.rs
+++ b/vendor/rayon/src/iter/step_by.rs
@@ -1,4 +1,3 @@
-#![cfg(has_step_by_rev)]
 use std::cmp::min;
 
 use super::plumbing::*;
diff --git a/vendor/rayon/src/iter/test.rs b/vendor/rayon/src/iter/test.rs
index bc5106bec..94323d79d 100644
--- a/vendor/rayon/src/iter/test.rs
+++ b/vendor/rayon/src/iter/test.rs
@@ -117,13 +117,10 @@ fn fold_map_reduce() {
     let r1 = (0_i32..32)
         .into_par_iter()
         .with_max_len(1)
-        .fold(
-            || vec![],
-            |mut v, e| {
-                v.push(e);
-                v
-            },
-        )
+        .fold(Vec::new, |mut v, e| {
+            v.push(e);
+            v
+        })
         .map(|v| vec![v])
         .reduce_with(|mut v_a, v_b| {
             v_a.extend(v_b);
@@ -394,7 +391,7 @@ fn check_slice_mut_indexed() {
 #[test]
 fn check_vec_indexed() {
     let a = vec![1, 2, 3];
-    is_indexed(a.clone().into_par_iter());
+    is_indexed(a.into_par_iter());
 }
 
 #[test]
@@ -1371,10 +1368,10 @@ fn check_find_is_present() {
     let counter = AtomicUsize::new(0);
     let value: Option<i32> = (0_i32..2048).into_par_iter().find_any(|&p| {
         counter.fetch_add(1, Ordering::SeqCst);
-        p >= 1024 && p < 1096
+        (1024..1096).contains(&p)
     });
     let q = value.unwrap();
-    assert!(q >= 1024 && q < 1096);
+    assert!((1024..1096).contains(&q));
     assert!(counter.load(Ordering::SeqCst) < 2048); // should not have visited every single one
 }
 
@@ -1892,7 +1889,7 @@ fn check_either() {
 
     // try an indexed iterator
     let left: E = Either::Left(v.clone().into_par_iter());
-    assert!(left.enumerate().eq(v.clone().into_par_iter().enumerate()));
+    assert!(left.enumerate().eq(v.into_par_iter().enumerate()));
 }
 
 #[test]
@@ -2063,7 +2060,7 @@ fn check_chunks_len() {
     assert_eq!(4, (0..8).into_par_iter().chunks(2).len());
     assert_eq!(3, (0..9).into_par_iter().chunks(3).len());
     assert_eq!(3, (0..8).into_par_iter().chunks(3).len());
-    assert_eq!(1, (&[1]).par_iter().chunks(3).len());
+    assert_eq!(1, [1].par_iter().chunks(3).len());
     assert_eq!(0, (0..0).into_par_iter().chunks(3).len());
 }
 
diff --git a/vendor/rayon/src/iter/try_fold.rs b/vendor/rayon/src/iter/try_fold.rs
index c1881d10f..6d1048d75 100644
--- a/vendor/rayon/src/iter/try_fold.rs
+++ b/vendor/rayon/src/iter/try_fold.rs
@@ -2,10 +2,9 @@ use super::plumbing::*;
 use super::ParallelIterator;
 use super::Try;
 
-use super::private::ControlFlow::{self, Break, Continue};
-
 use std::fmt::{self, Debug};
 use std::marker::PhantomData;
+use std::ops::ControlFlow::{self, Break, Continue};
 
 impl<U, I, ID, F> TryFold<I, U, ID, F>
 where
diff --git a/vendor/rayon/src/iter/try_reduce.rs b/vendor/rayon/src/iter/try_reduce.rs
index 7bf6cc4a5..35a724c94 100644
--- a/vendor/rayon/src/iter/try_reduce.rs
+++ b/vendor/rayon/src/iter/try_reduce.rs
@@ -2,8 +2,7 @@ use super::plumbing::*;
 use super::ParallelIterator;
 use super::Try;
 
-use super::private::ControlFlow::{self, Break, Continue};
-
+use std::ops::ControlFlow::{self, Break, Continue};
 use std::sync::atomic::{AtomicBool, Ordering};
 
 pub(super) fn try_reduce<PI, R, ID, T>(pi: PI, identity: ID, reduce_op: R) -> T
diff --git a/vendor/rayon/src/iter/try_reduce_with.rs b/vendor/rayon/src/iter/try_reduce_with.rs
index 9fe34d61d..cd7c83e27 100644
--- a/vendor/rayon/src/iter/try_reduce_with.rs
+++ b/vendor/rayon/src/iter/try_reduce_with.rs
@@ -2,8 +2,7 @@ use super::plumbing::*;
 use super::ParallelIterator;
 use super::Try;
 
-use super::private::ControlFlow::{self, Break, Continue};
-
+use std::ops::ControlFlow::{self, Break, Continue};
 use std::sync::atomic::{AtomicBool, Ordering};
 
 pub(super) fn try_reduce_with<PI, R, T>(pi: PI, reduce_op: R) -> Option<T>
diff --git a/vendor/rayon/src/iter/update.rs b/vendor/rayon/src/iter/update.rs
index 373a4d772..c693ac8d6 100644
--- a/vendor/rayon/src/iter/update.rs
+++ b/vendor/rayon/src/iter/update.rs
@@ -210,7 +210,7 @@ where
     F: Fn(&mut T) + Send + Sync,
 {
     fn split_off_left(&self) -> Self {
-        UpdateConsumer::new(self.base.split_off_left(), &self.update_op)
+        UpdateConsumer::new(self.base.split_off_left(), self.update_op)
     }
 
     fn to_reducer(&self) -> Self::Reducer {