From 9918693037dce8aa4bb6f08741b6812923486c18 Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Wed, 19 Jun 2024 11:26:03 +0200
Subject: Merging upstream version 1.76.0+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 vendor/itertools/tests/adaptors_no_collect.rs |  11 +-
 vendor/itertools/tests/merge_join.rs          |  69 ++--
 vendor/itertools/tests/quick.rs               | 314 ++++++++++-----
 vendor/itertools/tests/specializations.rs     | 310 +++++++++++++-
 vendor/itertools/tests/test_core.rs           |  77 ++--
 vendor/itertools/tests/test_std.rs            | 557 ++++++++++++++++++++------
 vendor/itertools/tests/zip.rs                 |  18 +-
 7 files changed, 1037 insertions(+), 319 deletions(-)

(limited to 'vendor/itertools/tests')

diff --git a/vendor/itertools/tests/adaptors_no_collect.rs b/vendor/itertools/tests/adaptors_no_collect.rs
index 103db23f1..977224af2 100644
--- a/vendor/itertools/tests/adaptors_no_collect.rs
+++ b/vendor/itertools/tests/adaptors_no_collect.rs
@@ -22,9 +22,14 @@ impl Iterator for PanickingCounter {
 }
 
 fn no_collect_test<A, T>(to_adaptor: T)
-    where A: Iterator, T: Fn(PanickingCounter) -> A
+where
+    A: Iterator,
+    T: Fn(PanickingCounter) -> A,
 {
-    let counter = PanickingCounter { curr: 0, max: 10_000 };
+    let counter = PanickingCounter {
+        curr: 0,
+        max: 10_000,
+    };
     let adaptor = to_adaptor(counter);
 
     for _ in adaptor.take(5) {}
@@ -43,4 +48,4 @@ fn combinations_no_collect() {
 #[test]
 fn combinations_with_replacement_no_collect() {
     no_collect_test(|iter| iter.combinations_with_replacement(5))
-}
\ No newline at end of file
+}
diff --git a/vendor/itertools/tests/merge_join.rs b/vendor/itertools/tests/merge_join.rs
index 3280b7d4e..776252fc5 100644
--- a/vendor/itertools/tests/merge_join.rs
+++ b/vendor/itertools/tests/merge_join.rs
@@ -1,108 +1,101 @@
-use itertools::EitherOrBoth;
 use itertools::free::merge_join_by;
+use itertools::EitherOrBoth;
 
 #[test]
 fn empty() {
     let left: Vec<u32> = vec![];
     let right: Vec<u32> = vec![];
-    let expected_result: Vec<EitherOrBoth<u32, u32>> = vec![];
-    let actual_result = merge_join_by(left, right, |l, r| l.cmp(r))
-        .collect::<Vec<_>>();
+    let expected_result: Vec<EitherOrBoth<u32>> = vec![];
+    let actual_result = merge_join_by(left, right, |l, r| l.cmp(r)).collect::<Vec<_>>();
     assert_eq!(expected_result, actual_result);
 }
 
 #[test]
 fn left_only() {
-    let left: Vec<u32> = vec![1,2,3];
+    let left: Vec<u32> = vec![1, 2, 3];
     let right: Vec<u32> = vec![];
-    let expected_result: Vec<EitherOrBoth<u32, u32>> = vec![
+    let expected_result: Vec<EitherOrBoth<u32>> = vec![
         EitherOrBoth::Left(1),
         EitherOrBoth::Left(2),
-        EitherOrBoth::Left(3)
+        EitherOrBoth::Left(3),
     ];
-    let actual_result = merge_join_by(left, right, |l, r| l.cmp(r))
-        .collect::<Vec<_>>();
+    let actual_result = merge_join_by(left, right, |l, r| l.cmp(r)).collect::<Vec<_>>();
     assert_eq!(expected_result, actual_result);
 }
 
 #[test]
 fn right_only() {
     let left: Vec<u32> = vec![];
-    let right: Vec<u32> = vec![1,2,3];
-    let expected_result: Vec<EitherOrBoth<u32, u32>> = vec![
+    let right: Vec<u32> = vec![1, 2, 3];
+    let expected_result: Vec<EitherOrBoth<u32>> = vec![
         EitherOrBoth::Right(1),
         EitherOrBoth::Right(2),
-        EitherOrBoth::Right(3)
+        EitherOrBoth::Right(3),
     ];
-    let actual_result = merge_join_by(left, right, |l, r| l.cmp(r))
-        .collect::<Vec<_>>();
+    let actual_result = merge_join_by(left, right, |l, r| l.cmp(r)).collect::<Vec<_>>();
     assert_eq!(expected_result, actual_result);
 }
 
 #[test]
 fn first_left_then_right() {
-    let left: Vec<u32> = vec![1,2,3];
-    let right: Vec<u32> = vec![4,5,6];
-    let expected_result: Vec<EitherOrBoth<u32, u32>> = vec![
+    let left: Vec<u32> = vec![1, 2, 3];
+    let right: Vec<u32> = vec![4, 5, 6];
+    let expected_result: Vec<EitherOrBoth<u32>> = vec![
         EitherOrBoth::Left(1),
         EitherOrBoth::Left(2),
         EitherOrBoth::Left(3),
         EitherOrBoth::Right(4),
         EitherOrBoth::Right(5),
-        EitherOrBoth::Right(6)
+        EitherOrBoth::Right(6),
     ];
-    let actual_result = merge_join_by(left, right, |l, r| l.cmp(r))
-        .collect::<Vec<_>>();
+    let actual_result = merge_join_by(left, right, |l, r| l.cmp(r)).collect::<Vec<_>>();
     assert_eq!(expected_result, actual_result);
 }
 
 #[test]
 fn first_right_then_left() {
-    let left: Vec<u32> = vec![4,5,6];
-    let right: Vec<u32> = vec![1,2,3];
-    let expected_result: Vec<EitherOrBoth<u32, u32>> = vec![
+    let left: Vec<u32> = vec![4, 5, 6];
+    let right: Vec<u32> = vec![1, 2, 3];
+    let expected_result: Vec<EitherOrBoth<u32>> = vec![
         EitherOrBoth::Right(1),
         EitherOrBoth::Right(2),
         EitherOrBoth::Right(3),
         EitherOrBoth::Left(4),
         EitherOrBoth::Left(5),
-        EitherOrBoth::Left(6)
+        EitherOrBoth::Left(6),
     ];
-    let actual_result = merge_join_by(left, right, |l, r| l.cmp(r))
-        .collect::<Vec<_>>();
+    let actual_result = merge_join_by(left, right, |l, r| l.cmp(r)).collect::<Vec<_>>();
     assert_eq!(expected_result, actual_result);
 }
 
 #[test]
 fn interspersed_left_and_right() {
-    let left: Vec<u32> = vec![1,3,5];
-    let right: Vec<u32> = vec![2,4,6];
-    let expected_result: Vec<EitherOrBoth<u32, u32>> = vec![
+    let left: Vec<u32> = vec![1, 3, 5];
+    let right: Vec<u32> = vec![2, 4, 6];
+    let expected_result: Vec<EitherOrBoth<u32>> = vec![
         EitherOrBoth::Left(1),
         EitherOrBoth::Right(2),
         EitherOrBoth::Left(3),
         EitherOrBoth::Right(4),
         EitherOrBoth::Left(5),
-        EitherOrBoth::Right(6)
+        EitherOrBoth::Right(6),
     ];
-    let actual_result = merge_join_by(left, right, |l, r| l.cmp(r))
-        .collect::<Vec<_>>();
+    let actual_result = merge_join_by(left, right, |l, r| l.cmp(r)).collect::<Vec<_>>();
     assert_eq!(expected_result, actual_result);
 }
 
 #[test]
 fn overlapping_left_and_right() {
-    let left: Vec<u32> = vec![1,3,4,6];
-    let right: Vec<u32> = vec![2,3,4,5];
-    let expected_result: Vec<EitherOrBoth<u32, u32>> = vec![
+    let left: Vec<u32> = vec![1, 3, 4, 6];
+    let right: Vec<u32> = vec![2, 3, 4, 5];
+    let expected_result: Vec<EitherOrBoth<u32>> = vec![
         EitherOrBoth::Left(1),
         EitherOrBoth::Right(2),
         EitherOrBoth::Both(3, 3),
         EitherOrBoth::Both(4, 4),
         EitherOrBoth::Right(5),
-        EitherOrBoth::Left(6)
+        EitherOrBoth::Left(6),
     ];
-    let actual_result = merge_join_by(left, right, |l, r| l.cmp(r))
-        .collect::<Vec<_>>();
+    let actual_result = merge_join_by(left, right, |l, r| l.cmp(r)).collect::<Vec<_>>();
     assert_eq!(expected_result, actual_result);
 }
diff --git a/vendor/itertools/tests/quick.rs b/vendor/itertools/tests/quick.rs
index c19af6c1e..6f45a63d0 100644
--- a/vendor/itertools/tests/quick.rs
+++ b/vendor/itertools/tests/quick.rs
@@ -3,34 +3,23 @@
 //!
 //! In particular we test the tedious size_hint and exact size correctness.
 
+#![allow(deprecated, unstable_name_collisions)]
+
+use itertools::free::{
+    cloned, enumerate, multipeek, peek_nth, put_back, put_back_n, rciter, zip, zip_eq,
+};
+use itertools::Itertools;
+use itertools::{iproduct, izip, multizip, EitherOrBoth};
 use quickcheck as qc;
+use std::cmp::{max, min, Ordering};
+use std::collections::{HashMap, HashSet};
 use std::default::Default;
 use std::num::Wrapping;
 use std::ops::Range;
-use std::cmp::{max, min, Ordering};
-use std::collections::{HashMap, HashSet};
-use itertools::Itertools;
-use itertools::{
-    multizip,
-    EitherOrBoth,
-    iproduct,
-    izip,
-};
-use itertools::free::{
-    cloned,
-    enumerate,
-    multipeek,
-    peek_nth,
-    put_back,
-    put_back_n,
-    rciter,
-    zip,
-    zip_eq,
-};
 
-use rand::Rng;
-use rand::seq::SliceRandom;
 use quickcheck::TestResult;
+use rand::seq::SliceRandom;
+use rand::Rng;
 
 /// Trait for size hint modifier types
 trait HintKind: Copy + Send + qc::Arbitrary {
@@ -66,8 +55,10 @@ struct Inexact {
 impl HintKind for Inexact {
     fn loosen_bounds(&self, org_hint: (usize, Option<usize>)) -> (usize, Option<usize>) {
         let (org_lower, org_upper) = org_hint;
-        (org_lower.saturating_sub(self.underestimate),
-         org_upper.and_then(move |x| x.checked_add(self.overestimate)))
+        (
+            org_lower.saturating_sub(self.underestimate),
+            org_upper.and_then(move |x| x.checked_add(self.overestimate)),
+        )
     }
 }
 
@@ -84,19 +75,15 @@ impl qc::Arbitrary for Inexact {
         }
     }
 
-    fn shrink(&self) -> Box<dyn Iterator<Item=Self>> {
+    fn shrink(&self) -> Box<dyn Iterator<Item = Self>> {
         let underestimate_value = self.underestimate;
         let overestimate_value = self.overestimate;
-        Box::new(
-            underestimate_value.shrink().flat_map(move |ue_value|
-                overestimate_value.shrink().map(move |oe_value|
-                    Inexact {
-                        underestimate: ue_value,
-                        overestimate: oe_value,
-                    }
-                )
-            )
-        )
+        Box::new(underestimate_value.shrink().flat_map(move |ue_value| {
+            overestimate_value.shrink().map(move |oe_value| Inexact {
+                underestimate: ue_value,
+                overestimate: oe_value,
+            })
+        }))
     }
 }
 
@@ -116,7 +103,9 @@ struct Iter<T, SK: HintKind = Inexact> {
     hint_kind: SK,
 }
 
-impl<T, HK> Iter<T, HK> where HK: HintKind
+impl<T, HK> Iter<T, HK>
+where
+    HK: HintKind,
 {
     fn new(it: Range<T>, hint_kind: HK) -> Self {
         Iter {
@@ -128,64 +117,66 @@ impl<T, HK> Iter<T, HK> where HK: HintKind
 }
 
 impl<T, HK> Iterator for Iter<T, HK>
-    where Range<T>: Iterator,
-          <Range<T> as Iterator>::Item: Default,
-          HK: HintKind,
+where
+    Range<T>: Iterator,
+    <Range<T> as Iterator>::Item: Default,
+    HK: HintKind,
 {
     type Item = <Range<T> as Iterator>::Item;
 
-    fn next(&mut self) -> Option<Self::Item>
-    {
+    fn next(&mut self) -> Option<Self::Item> {
         let elt = self.iterator.next();
         if elt.is_none() {
             self.fuse_flag += 1;
             // check fuse flag
             if self.fuse_flag == 2 {
-                return Some(Default::default())
+                return Some(Default::default());
             }
         }
         elt
     }
 
-    fn size_hint(&self) -> (usize, Option<usize>)
-    {
+    fn size_hint(&self) -> (usize, Option<usize>) {
         let org_hint = self.iterator.size_hint();
         self.hint_kind.loosen_bounds(org_hint)
     }
 }
 
 impl<T, HK> DoubleEndedIterator for Iter<T, HK>
-    where Range<T>: DoubleEndedIterator,
-          <Range<T> as Iterator>::Item: Default,
-          HK: HintKind
+where
+    Range<T>: DoubleEndedIterator,
+    <Range<T> as Iterator>::Item: Default,
+    HK: HintKind,
 {
-    fn next_back(&mut self) -> Option<Self::Item> { self.iterator.next_back() }
+    fn next_back(&mut self) -> Option<Self::Item> {
+        self.iterator.next_back()
+    }
 }
 
-impl<T> ExactSizeIterator for Iter<T, Exact> where Range<T>: ExactSizeIterator,
+impl<T> ExactSizeIterator for Iter<T, Exact>
+where
+    Range<T>: ExactSizeIterator,
     <Range<T> as Iterator>::Item: Default,
-{ }
+{
+}
 
 impl<T, HK> qc::Arbitrary for Iter<T, HK>
-    where T: qc::Arbitrary,
-          HK: HintKind,
+where
+    T: qc::Arbitrary,
+    HK: HintKind,
 {
-    fn arbitrary<G: qc::Gen>(g: &mut G) -> Self
-    {
+    fn arbitrary<G: qc::Gen>(g: &mut G) -> Self {
         Iter::new(T::arbitrary(g)..T::arbitrary(g), HK::arbitrary(g))
     }
 
-    fn shrink(&self) -> Box<dyn Iterator<Item=Iter<T, HK>>>
-    {
+    fn shrink(&self) -> Box<dyn Iterator<Item = Iter<T, HK>>> {
         let r = self.iterator.clone();
         let hint_kind = self.hint_kind;
-        Box::new(
-            r.start.shrink().flat_map(move |a|
-                r.end.shrink().map(move |b|
-                    Iter::new(a.clone()..b, hint_kind)
-                )
-            )
-        )
+        Box::new(r.start.shrink().flat_map(move |a| {
+            r.end
+                .shrink()
+                .map(move |b| Iter::new(a.clone()..b, hint_kind))
+        }))
     }
 }
 
@@ -201,7 +192,10 @@ struct ShiftRange<HK = Inexact> {
     hint_kind: HK,
 }
 
-impl<HK> Iterator for ShiftRange<HK> where HK: HintKind {
+impl<HK> Iterator for ShiftRange<HK>
+where
+    HK: HintKind,
+{
     type Item = Iter<i32, HK>;
 
     fn next(&mut self) -> Option<Self::Item> {
@@ -219,10 +213,11 @@ impl<HK> Iterator for ShiftRange<HK> where HK: HintKind {
     }
 }
 
-impl ExactSizeIterator for ShiftRange<Exact> { }
+impl ExactSizeIterator for ShiftRange<Exact> {}
 
 impl<HK> qc::Arbitrary for ShiftRange<HK>
-    where HK: HintKind
+where
+    HK: HintKind,
 {
     fn arbitrary<G: qc::Gen>(g: &mut G) -> Self {
         const MAX_STARTING_RANGE_DIFF: i32 = 32;
@@ -250,7 +245,7 @@ impl<HK> qc::Arbitrary for ShiftRange<HK>
 fn correct_count<I, F>(get_it: F) -> bool
 where
     I: Iterator,
-    F: Fn() -> I
+    F: Fn() -> I,
 {
     let mut counts = vec![get_it().count()];
 
@@ -276,7 +271,10 @@ where
     for (i, returned_count) in counts.into_iter().enumerate() {
         let actual_count = total_actual_count - i;
         if actual_count != returned_count {
-            println!("Total iterations: {} True count: {} returned count: {}", i, actual_count, returned_count);
+            println!(
+                "Total iterations: {} True count: {} returned count: {}",
+                i, actual_count, returned_count
+            );
 
             return false;
         }
@@ -299,12 +297,10 @@ fn correct_size_hint<I: Iterator>(mut it: I) -> bool {
     // check all the size hints
     for &(low, hi) in &hints {
         true_count -= 1;
-        if low > true_count ||
-            (hi.is_some() && hi.unwrap() < true_count)
-        {
+        if low > true_count || (hi.is_some() && hi.unwrap() < true_count) {
             println!("True size: {:?}, size hint: {:?}", true_count, (low, hi));
             //println!("All hints: {:?}", hints);
-            return false
+            return false;
         }
     }
     true
@@ -313,13 +309,19 @@ fn correct_size_hint<I: Iterator>(mut it: I) -> bool {
 fn exact_size<I: ExactSizeIterator>(mut it: I) -> bool {
     // check every iteration
     let (mut low, mut hi) = it.size_hint();
-    if Some(low) != hi { return false; }
+    if Some(low) != hi {
+        return false;
+    }
     while let Some(_) = it.next() {
         let (xlow, xhi) = it.size_hint();
-        if low != xlow + 1 { return false; }
+        if low != xlow + 1 {
+            return false;
+        }
         low = xlow;
         hi = xhi;
-        if Some(low) != hi { return false; }
+        if Some(low) != hi {
+            return false;
+        }
     }
     let (low, hi) = it.size_hint();
     low == 0 && hi == Some(0)
@@ -329,13 +331,19 @@ fn exact_size<I: ExactSizeIterator>(mut it: I) -> bool {
 fn exact_size_for_this<I: Iterator>(mut it: I) -> bool {
     // check every iteration
     let (mut low, mut hi) = it.size_hint();
-    if Some(low) != hi { return false; }
+    if Some(low) != hi {
+        return false;
+    }
     while let Some(_) = it.next() {
         let (xlow, xhi) = it.size_hint();
-        if low != xlow + 1 { return false; }
+        if low != xlow + 1 {
+            return false;
+        }
         low = xlow;
         hi = xhi;
-        if Some(low) != hi { return false; }
+        if Some(low) != hi {
+            return false;
+        }
     }
     let (low, hi) = it.size_hint();
     low == 0 && hi == Some(0)
@@ -750,6 +758,56 @@ quickcheck! {
     }
 }
 
+quickcheck! {
+    fn correct_peek_nth(mut a: Vec<u16>) -> () {
+        let mut it = peek_nth(a.clone());
+        for start_pos in 0..a.len() + 2 {
+            for real_idx in start_pos..a.len() + 2 {
+                let peek_idx = real_idx - start_pos;
+                assert_eq!(it.peek_nth(peek_idx), a.get(real_idx));
+                assert_eq!(it.peek_nth_mut(peek_idx), a.get_mut(real_idx));
+            }
+            assert_eq!(it.next(), a.get(start_pos).copied());
+        }
+    }
+
+    fn peek_nth_mut_replace(a: Vec<u16>, b: Vec<u16>) -> () {
+        let mut it = peek_nth(a.iter());
+        for i in 0..a.len().min(b.len()) {
+            *it.peek_nth_mut(i).unwrap() = &b[i];
+        }
+        for i in 0..a.len() {
+            assert_eq!(it.next().unwrap(), b.get(i).unwrap_or(&a[i]));
+        }
+        assert_eq!(it.next(), None);
+        assert_eq!(it.next(), None);
+    }
+
+    fn peek_nth_next_if(a: Vec<u8>) -> () {
+        let mut it = peek_nth(a.clone());
+        for (idx, mut value) in a.iter().copied().enumerate() {
+            let should_be_none = it.next_if(|x| x != &value);
+            assert_eq!(should_be_none, None);
+            if value % 5 == 0 {
+                // Sometimes, peek up to 3 further.
+                let n = value as usize % 3;
+                let nth = it.peek_nth(n);
+                assert_eq!(nth, a.get(idx + n));
+            } else if value % 5 == 1 {
+                // Sometimes, peek next element mutably.
+                if let Some(v) = it.peek_mut() {
+                    *v = v.wrapping_sub(1);
+                    let should_be_none = it.next_if_eq(&value);
+                    assert_eq!(should_be_none, None);
+                    value = value.wrapping_sub(1);
+                }
+            }
+            let eq = it.next_if_eq(&value);
+            assert_eq!(eq, Some(value));
+        }
+    }
+}
+
 quickcheck! {
     fn dedup_via_coalesce(a: Vec<i32>) -> bool {
         let mut b = a.clone();
@@ -895,8 +953,31 @@ quickcheck! {
 }
 
 quickcheck! {
-    fn size_combinations(it: Iter<i16>) -> bool {
-        correct_size_hint(it.tuple_combinations::<(_, _)>())
+    fn size_combinations(a: Iter<i16>) -> bool {
+        let it = a.clone().tuple_combinations::<(_, _)>();
+        correct_size_hint(it.clone()) && it.count() == binomial(a.count(), 2)
+    }
+
+    fn exact_size_combinations_1(a: Vec<u8>) -> bool {
+        let it = a.iter().tuple_combinations::<(_,)>();
+        exact_size_for_this(it.clone()) && it.count() == binomial(a.len(), 1)
+    }
+    fn exact_size_combinations_2(a: Vec<u8>) -> bool {
+        let it = a.iter().tuple_combinations::<(_, _)>();
+        exact_size_for_this(it.clone()) && it.count() == binomial(a.len(), 2)
+    }
+    fn exact_size_combinations_3(mut a: Vec<u8>) -> bool {
+        a.truncate(15);
+        let it = a.iter().tuple_combinations::<(_, _, _)>();
+        exact_size_for_this(it.clone()) && it.count() == binomial(a.len(), 3)
+    }
+}
+
+fn binomial(n: usize, k: usize) -> usize {
+    if k > n {
+        0
+    } else {
+        (n - k + 1..=n).product::<usize>() / (1..=k).product::<usize>()
     }
 }
 
@@ -1111,6 +1192,10 @@ quickcheck! {
         true
     }
 
+    fn circular_tuple_windows_exact_size(a: Vec<u8>) -> bool {
+        exact_size(a.iter().circular_tuple_windows::<(_, _, _, _)>())
+    }
+
     fn equal_tuple_windows_1(a: Vec<u8>) -> bool {
         let x = a.windows(1).map(|s| (&s[0], ));
         let y = a.iter().tuple_windows::<(_,)>();
@@ -1135,6 +1220,14 @@ quickcheck! {
         itertools::equal(x, y)
     }
 
+    fn tuple_windows_exact_size_1(a: Vec<u8>) -> bool {
+        exact_size(a.iter().tuple_windows::<(_,)>())
+    }
+
+    fn tuple_windows_exact_size_4(a: Vec<u8>) -> bool {
+        exact_size(a.iter().tuple_windows::<(_, _, _, _)>())
+    }
+
     fn equal_tuples_1(a: Vec<u8>) -> bool {
         let x = a.chunks(1).map(|s| (&s[0], ));
         let y = a.iter().tuples::<(_,)>();
@@ -1166,6 +1259,18 @@ quickcheck! {
         assert_eq!(buffer.len(), a.len() % 4);
         exact_size(buffer)
     }
+
+    fn tuples_size_hint_inexact(a: Iter<u8>) -> bool {
+        correct_size_hint(a.clone().tuples::<(_,)>())
+            && correct_size_hint(a.clone().tuples::<(_, _)>())
+            && correct_size_hint(a.tuples::<(_, _, _, _)>())
+    }
+
+    fn tuples_size_hint_exact(a: Iter<u8, Exact>) -> bool {
+        exact_size(a.clone().tuples::<(_,)>())
+            && exact_size(a.clone().tuples::<(_, _)>())
+            && exact_size(a.tuples::<(_, _, _, _)>())
+    }
 }
 
 // with_position
@@ -1332,7 +1437,7 @@ quickcheck! {
                     Some(acc.unwrap_or(0) + val)
                 }
             });
-        
+
         let group_map_lookup = a.iter()
             .map(|&b| b as u64)
             .map(|i| (i % modulo, i))
@@ -1352,7 +1457,7 @@ quickcheck! {
 
         for m in 0..modulo {
             assert_eq!(
-                lookup.get(&m).copied(), 
+                lookup.get(&m).copied(),
                 a.iter()
                     .map(|&b| b as u64)
                     .filter(|&val| val % modulo == m)
@@ -1367,6 +1472,35 @@ quickcheck! {
         }
     }
 
+    fn correct_grouping_map_by_fold_with_modulo_key(a: Vec<u8>, modulo: u8) -> () {
+        #[derive(Debug, Default, PartialEq)]
+        struct Accumulator {
+            acc: u64,
+        }
+
+        let modulo = if modulo == 0 { 1 } else { modulo } as u64; // Avoid `% 0`
+        let lookup = a.iter().map(|&b| b as u64) // Avoid overflows
+            .into_grouping_map_by(|i| i % modulo)
+            .fold_with(|_key, _val| Default::default(), |Accumulator { acc }, &key, val| {
+                assert!(val % modulo == key);
+                let acc = acc + val;
+                Accumulator { acc }
+            });
+
+        let group_map_lookup = a.iter()
+            .map(|&b| b as u64)
+            .map(|i| (i % modulo, i))
+            .into_group_map()
+            .into_iter()
+            .map(|(key, vals)| (key, vals.into_iter().sum())).map(|(key, acc)| (key,Accumulator { acc }))
+            .collect::<HashMap<_,_>>();
+        assert_eq!(lookup, group_map_lookup);
+
+        for (&key, &Accumulator { acc: sum }) in lookup.iter() {
+            assert_eq!(sum, a.iter().map(|&b| b as u64).filter(|&val| val % modulo == key).sum::<u64>());
+        }
+    }
+
     fn correct_grouping_map_by_fold_modulo_key(a: Vec<u8>, modulo: u8) -> () {
         let modulo = if modulo == 0 { 1 } else { modulo } as u64; // Avoid `% 0`
         let lookup = a.iter().map(|&b| b as u64) // Avoid overflows
@@ -1472,7 +1606,7 @@ quickcheck! {
             assert_eq!(Some(max), a.iter().copied().filter(|&val| val % modulo == key).max_by_key(|&val| val));
         }
     }
-    
+
     fn correct_grouping_map_by_min_modulo_key(a: Vec<u8>, modulo: u8) -> () {
         let modulo = if modulo == 0 { 1 } else { modulo }; // Avoid `% 0`
         let lookup = a.iter().copied().into_grouping_map_by(|i| i % modulo).min();
@@ -1523,7 +1657,7 @@ quickcheck! {
             assert_eq!(Some(min), a.iter().copied().filter(|&val| val % modulo == key).min_by_key(|&val| val));
         }
     }
-    
+
     fn correct_grouping_map_by_minmax_modulo_key(a: Vec<u8>, modulo: u8) -> () {
         let modulo = if modulo == 0 { 1 } else { modulo }; // Avoid `% 0`
         let lookup = a.iter().copied().into_grouping_map_by(|i| i % modulo).minmax();
@@ -1636,7 +1770,7 @@ quickcheck! {
             .min_by(|_, _, _| Ordering::Equal);
 
         assert_eq!(lookup[&0], 0);
-        
+
         let lookup = (0..=10)
             .into_grouping_map_by(|_| 0)
             .minmax_by(|_, _, _| Ordering::Equal);
@@ -1694,12 +1828,10 @@ quickcheck! {
     }
 }
 
-
-fn is_fused<I: Iterator>(mut it: I) -> bool
-{
+fn is_fused<I: Iterator>(mut it: I) -> bool {
     for _ in it.by_ref() {}
-    for _ in 0..10{
-        if it.next().is_some(){
+    for _ in 0..10 {
+        if it.next().is_some() {
             return false;
         }
     }
@@ -1740,7 +1872,7 @@ quickcheck! {
         !is_fused(a.clone().interleave_shortest(b.clone())) &&
         is_fused(a.fuse().interleave_shortest(b.fuse()))
     }
-    
+
     fn fused_product(a: Iter<i16>, b: Iter<i16>) -> bool
     {
         is_fused(a.fuse().cartesian_product(b.fuse()))
diff --git a/vendor/itertools/tests/specializations.rs b/vendor/itertools/tests/specializations.rs
index 057e11c9f..fe14234d6 100644
--- a/vendor/itertools/tests/specializations.rs
+++ b/vendor/itertools/tests/specializations.rs
@@ -1,6 +1,8 @@
+#![allow(unstable_name_collisions)]
+
 use itertools::Itertools;
+use quickcheck::{quickcheck, TestResult};
 use std::fmt::Debug;
-use quickcheck::quickcheck;
 
 struct Unspecialized<I>(I);
 impl<I> Iterator for Unspecialized<I>
@@ -15,24 +17,25 @@ where
     }
 }
 
-macro_rules! check_specialized {
-    ($src:expr, |$it:pat| $closure:expr) => {
-        let $it = $src.clone();
-        let v1 = $closure;
-
-        let $it = Unspecialized($src.clone());
-        let v2 = $closure;
-
-        assert_eq!(v1, v2);
-    }
-}
-
-fn test_specializations<IterItem, Iter>(
-    it: &Iter,
-) where
+fn test_specializations<IterItem, Iter>(it: &Iter)
+where
     IterItem: Eq + Debug + Clone,
     Iter: Iterator<Item = IterItem> + Clone,
 {
+    macro_rules! check_specialized {
+        ($src:expr, |$it:pat| $closure:expr) => {
+            // Many iterators special-case the first elements, so we test specializations for iterators that have already been advanced.
+            let mut src = $src.clone();
+            for _ in 0..5 {
+                let $it = src.clone();
+                let v1 = $closure;
+                let $it = Unspecialized(src.clone());
+                let v2 = $closure;
+                assert_eq!(v1, v2);
+                src.next();
+            }
+        }
+    }
     check_specialized!(it, |i| i.count());
     check_specialized!(it, |i| i.last());
     check_specialized!(it, |i| i.collect::<Vec<_>>());
@@ -50,7 +53,7 @@ fn test_specializations<IterItem, Iter>(
         let first = i.next();
         let all_result = i.all(|x| {
             parameters_from_all.push(x.clone());
-            Some(x)==first
+            Some(x) == first
         });
         (parameters_from_all, all_result)
     });
@@ -73,9 +76,188 @@ fn test_specializations<IterItem, Iter>(
 }
 
 quickcheck! {
+    fn interleave(v: Vec<u8>, w: Vec<u8>) -> () {
+        test_specializations(&v.iter().interleave(w.iter()));
+    }
+
+    fn interleave_shortest(v: Vec<u8>, w: Vec<u8>) -> () {
+        test_specializations(&v.iter().interleave_shortest(w.iter()));
+    }
+
+    fn batching(v: Vec<u8>) -> () {
+        test_specializations(&v.iter().batching(Iterator::next));
+    }
+
+    fn tuple_windows(v: Vec<u8>) -> () {
+        test_specializations(&v.iter().tuple_windows::<(_,)>());
+        test_specializations(&v.iter().tuple_windows::<(_, _)>());
+        test_specializations(&v.iter().tuple_windows::<(_, _, _)>());
+    }
+
+    fn circular_tuple_windows(v: Vec<u8>) -> () {
+        test_specializations(&v.iter().circular_tuple_windows::<(_,)>());
+        test_specializations(&v.iter().circular_tuple_windows::<(_, _)>());
+        test_specializations(&v.iter().circular_tuple_windows::<(_, _, _)>());
+    }
+
+    fn tuples(v: Vec<u8>) -> () {
+        test_specializations(&v.iter().tuples::<(_,)>());
+        test_specializations(&v.iter().tuples::<(_, _)>());
+        test_specializations(&v.iter().tuples::<(_, _, _)>());
+    }
+
+    fn cartesian_product(a: Vec<u8>, b: Vec<u8>) -> TestResult {
+        if a.len() * b.len() > 100 {
+            return TestResult::discard();
+        }
+        test_specializations(&a.iter().cartesian_product(&b));
+        TestResult::passed()
+    }
+
+    #[ignore] // It currently fails because `MultiProduct` is not fused.
+    fn multi_cartesian_product(a: Vec<u8>, b: Vec<u8>, c: Vec<u8>) -> TestResult {
+        if a.len() * b.len() * c.len() > 100 {
+            return TestResult::discard();
+        }
+        test_specializations(&vec![a, b, c].into_iter().multi_cartesian_product());
+        TestResult::passed()
+    }
+
+    fn coalesce(v: Vec<u8>) -> () {
+        test_specializations(&v.iter().coalesce(|x, y| if x == y { Ok(x) } else { Err((x, y)) }))
+    }
+
+    fn dedup(v: Vec<u8>) -> () {
+        test_specializations(&v.iter().dedup())
+    }
+
+    fn dedup_by(v: Vec<u8>) -> () {
+        test_specializations(&v.iter().dedup_by(PartialOrd::ge))
+    }
+
+    fn dedup_with_count(v: Vec<u8>) -> () {
+        test_specializations(&v.iter().dedup_with_count())
+    }
+
+    fn dedup_by_with_count(v: Vec<u8>) -> () {
+        test_specializations(&v.iter().dedup_by_with_count(PartialOrd::ge))
+    }
+
+    fn duplicates(v: Vec<u8>) -> () {
+        test_specializations(&v.iter().duplicates());
+    }
+
+    fn duplicates_by(v: Vec<u8>) -> () {
+        test_specializations(&v.iter().duplicates_by(|x| *x % 10));
+    }
+
+    fn unique(v: Vec<u8>) -> () {
+        test_specializations(&v.iter().unique());
+    }
+
+    fn unique_by(v: Vec<u8>) -> () {
+        test_specializations(&v.iter().unique_by(|x| *x % 50));
+    }
+
+    fn take_while_inclusive(v: Vec<u8>) -> () {
+        test_specializations(&v.iter().copied().take_while_inclusive(|&x| x < 100));
+    }
+
+    fn while_some(v: Vec<u8>) -> () {
+        test_specializations(&v.iter().map(|&x| if x < 100 { Some(2 * x) } else { None }).while_some());
+    }
+
+    fn pad_using(v: Vec<u8>) -> () {
+        use std::convert::TryFrom;
+        test_specializations(&v.iter().copied().pad_using(10, |i| u8::try_from(5 * i).unwrap_or(u8::MAX)));
+    }
+
+    fn with_position(v: Vec<u8>) -> () {
+        test_specializations(&v.iter().with_position());
+    }
+
+    fn positions(v: Vec<u8>) -> () {
+        test_specializations(&v.iter().positions(|x| x % 5 == 0));
+    }
+
+    fn update(v: Vec<u8>) -> () {
+        test_specializations(&v.iter().copied().update(|x| *x = x.wrapping_mul(7)));
+    }
+
+    fn tuple_combinations(v: Vec<u8>) -> TestResult {
+        if v.len() > 10 {
+            return TestResult::discard();
+        }
+        test_specializations(&v.iter().tuple_combinations::<(_,)>());
+        test_specializations(&v.iter().tuple_combinations::<(_, _)>());
+        test_specializations(&v.iter().tuple_combinations::<(_, _, _)>());
+        TestResult::passed()
+    }
+
     fn intersperse(v: Vec<u8>) -> () {
         test_specializations(&v.into_iter().intersperse(0));
     }
+
+    fn intersperse_with(v: Vec<u8>) -> () {
+        test_specializations(&v.into_iter().intersperse_with(|| 0));
+    }
+
+    fn combinations(a: Vec<u8>, n: u8) -> TestResult {
+        if n > 3 || a.len() > 8 {
+            return TestResult::discard();
+        }
+        test_specializations(&a.iter().combinations(n as usize));
+        TestResult::passed()
+    }
+
+    fn combinations_with_replacement(a: Vec<u8>, n: u8) -> TestResult {
+        if n > 3 || a.len() > 7 {
+            return TestResult::discard();
+        }
+        test_specializations(&a.iter().combinations_with_replacement(n as usize));
+        TestResult::passed()
+    }
+
+    fn permutations(a: Vec<u8>, n: u8) -> TestResult {
+        if n > 3 || a.len() > 8 {
+            return TestResult::discard();
+        }
+        test_specializations(&a.iter().permutations(n as usize));
+        TestResult::passed()
+    }
+
+    fn powerset(a: Vec<u8>) -> TestResult {
+        if a.len() > 6 {
+            return TestResult::discard();
+        }
+        test_specializations(&a.iter().powerset());
+        TestResult::passed()
+    }
+
+    fn zip_longest(a: Vec<u8>, b: Vec<u8>) -> () {
+        test_specializations(&a.into_iter().zip_longest(b))
+    }
+
+    fn zip_eq(a: Vec<u8>) -> () {
+        test_specializations(&a.iter().zip_eq(a.iter().rev()))
+    }
+
+    fn multizip(a: Vec<u8>) -> () {
+        let its = (a.iter(), a.iter().rev(), a.iter().take(50));
+        test_specializations(&itertools::multizip(its));
+    }
+
+    fn izip(a: Vec<u8>, b: Vec<u8>) -> () {
+        test_specializations(&itertools::izip!(b.iter(), a, b.iter().rev()));
+    }
+
+    fn iproduct(a: Vec<u8>, b: Vec<u8>, c: Vec<u8>) -> TestResult {
+        if a.len() * b.len() * c.len() > 200 {
+            return TestResult::discard();
+        }
+        test_specializations(&itertools::iproduct!(a, b.iter(), c));
+        TestResult::passed()
+    }
 }
 
 quickcheck! {
@@ -85,11 +267,85 @@ quickcheck! {
         pb.put_back(1);
         test_specializations(&pb);
     }
+
+    fn put_back_n(v: Vec<u8>, n: u8) -> () {
+        let mut it = itertools::put_back_n(v);
+        for k in 0..n {
+            it.put_back(k);
+        }
+        test_specializations(&it);
+    }
+
+    fn multipeek(v: Vec<u8>, n: u8) -> () {
+        let mut it = v.into_iter().multipeek();
+        for _ in 0..n {
+            it.peek();
+        }
+        test_specializations(&it);
+    }
+
+    fn peek_nth_with_peek(v: Vec<u8>, n: u8) -> () {
+        let mut it = itertools::peek_nth(v);
+        for _ in 0..n {
+            it.peek();
+        }
+        test_specializations(&it);
+    }
+
+    fn peek_nth_with_peek_nth(v: Vec<u8>, n: u8) -> () {
+        let mut it = itertools::peek_nth(v);
+        it.peek_nth(n as usize);
+        test_specializations(&it);
+    }
+
+    fn peek_nth_with_peek_mut(v: Vec<u8>, n: u8) -> () {
+        let mut it = itertools::peek_nth(v);
+        for _ in 0..n {
+            if let Some(x) = it.peek_mut() {
+                *x = x.wrapping_add(50);
+            }
+        }
+        test_specializations(&it);
+    }
+
+    fn peek_nth_with_peek_nth_mut(v: Vec<u8>, n: u8) -> () {
+        let mut it = itertools::peek_nth(v);
+        if let Some(x) = it.peek_nth_mut(n as usize) {
+            *x = x.wrapping_add(50);
+        }
+        test_specializations(&it);
+    }
 }
 
 quickcheck! {
-    fn merge_join_by_qc(i1: Vec<usize>, i2: Vec<usize>) -> () {
-        test_specializations(&i1.into_iter().merge_join_by(i2.into_iter(), std::cmp::Ord::cmp));
+    fn merge(a: Vec<u8>, b: Vec<u8>) -> () {
+        test_specializations(&a.into_iter().merge(b))
+    }
+
+    fn merge_by(a: Vec<u8>, b: Vec<u8>) -> () {
+        test_specializations(&a.into_iter().merge_by(b, PartialOrd::ge))
+    }
+
+    fn merge_join_by_ordering(i1: Vec<u8>, i2: Vec<u8>) -> () {
+        test_specializations(&i1.into_iter().merge_join_by(i2, Ord::cmp));
+    }
+
+    fn merge_join_by_bool(i1: Vec<u8>, i2: Vec<u8>) -> () {
+        test_specializations(&i1.into_iter().merge_join_by(i2, PartialOrd::ge));
+    }
+
+    fn kmerge(a: Vec<i8>, b: Vec<i8>, c: Vec<i8>) -> () {
+        test_specializations(&vec![a, b, c]
+            .into_iter()
+            .map(|v| v.into_iter().sorted())
+            .kmerge());
+    }
+
+    fn kmerge_by(a: Vec<i8>, b: Vec<i8>, c: Vec<i8>) -> () {
+        test_specializations(&vec![a, b, c]
+            .into_iter()
+            .map(|v| v.into_iter().sorted_by_key(|a| a.abs()))
+            .kmerge_by(|a, b| a.abs() < b.abs()));
     }
 }
 
@@ -97,15 +353,27 @@ quickcheck! {
     fn map_into(v: Vec<u8>) -> () {
         test_specializations(&v.into_iter().map_into::<u32>());
     }
-}
 
-quickcheck! {
     fn map_ok(v: Vec<Result<u8, char>>) -> () {
         test_specializations(&v.into_iter().map_ok(|u| u.checked_add(1)));
     }
+
+    fn filter_ok(v: Vec<Result<u8, char>>) -> () {
+        test_specializations(&v.into_iter().filter_ok(|&i| i < 20));
+    }
+
+    fn filter_map_ok(v: Vec<Result<u8, char>>) -> () {
+        test_specializations(&v.into_iter().filter_map_ok(|i| if i < 20 { Some(i * 2) } else { None }));
+    }
+
+    // `Option<u8>` because `Vec<u8>` would be very slow!! And we can't give `[u8; 3]`.
+    fn flatten_ok(v: Vec<Result<Option<u8>, char>>) -> () {
+        test_specializations(&v.into_iter().flatten_ok());
+    }
 }
 
 quickcheck! {
+    // TODO Replace this function by a normal call to test_specializations
     fn process_results(v: Vec<Result<u8, u8>>) -> () {
         helper(v.iter().copied());
         helper(v.iter().copied().filter(Result::is_ok));
diff --git a/vendor/itertools/tests/test_core.rs b/vendor/itertools/tests/test_core.rs
index df94eb665..c624a7e33 100644
--- a/vendor/itertools/tests/test_core.rs
+++ b/vendor/itertools/tests/test_core.rs
@@ -4,18 +4,19 @@
 //! option. This file may not be copied, modified, or distributed
 //! except according to those terms.
 #![no_std]
+#![allow(deprecated)]
 
-use core::iter;
-use itertools as it;
-use crate::it::Itertools;
+use crate::it::chain;
+use crate::it::free::put_back;
 use crate::it::interleave;
 use crate::it::intersperse;
 use crate::it::intersperse_with;
-use crate::it::multizip;
-use crate::it::free::put_back;
 use crate::it::iproduct;
 use crate::it::izip;
-use crate::it::chain;
+use crate::it::multizip;
+use crate::it::Itertools;
+use core::iter;
+use itertools as it;
 
 #[test]
 fn product2() {
@@ -34,13 +35,12 @@ fn product_temporary() {
     for (_x, _y, _z) in iproduct!(
         [0, 1, 2].iter().cloned(),
         [0, 1, 2].iter().cloned(),
-        [0, 1, 2].iter().cloned())
-    {
+        [0, 1, 2].iter().cloned()
+    ) {
         // ok
     }
 }
 
-
 #[test]
 fn izip_macro() {
     let mut zip = izip!(2..3);
@@ -61,7 +61,7 @@ fn izip_macro() {
 #[test]
 fn izip2() {
     let _zip1: iter::Zip<_, _> = izip!(1.., 2..);
-    let _zip2: iter::Zip<_, _> = izip!(1.., 2.., );
+    let _zip2: iter::Zip<_, _> = izip!(1.., 2..,);
 }
 
 #[test]
@@ -109,7 +109,7 @@ fn chain_macro() {
 #[test]
 fn chain2() {
     let _ = chain!(1.., 2..);
-    let _ = chain!(1.., 2.., );
+    let _ = chain!(1.., 2..,);
 }
 
 #[test]
@@ -127,7 +127,7 @@ fn write_to() {
 
 #[test]
 fn test_interleave() {
-    let xs: [u8; 0]  = [];
+    let xs: [u8; 0] = [];
     let ys = [7u8, 9, 8, 10];
     let zs = [2u8, 77];
     let it = interleave(xs.iter(), ys.iter());
@@ -211,7 +211,6 @@ fn merge() {
     it::assert_equal((0..10).step(2).merge((1..10).step(2)), 0..10);
 }
 
-
 #[test]
 fn repeatn() {
     let s = "α";
@@ -231,29 +230,33 @@ fn count_clones() {
     use core::cell::Cell;
     #[derive(PartialEq, Debug)]
     struct Foo {
-        n: Cell<usize>
+        n: Cell<usize>,
     }
 
-    impl Clone for Foo
-    {
-        fn clone(&self) -> Self
-        {
+    impl Clone for Foo {
+        fn clone(&self) -> Self {
             let n = self.n.get();
             self.n.set(n + 1);
-            Foo { n: Cell::new(n + 1) }
+            Foo {
+                n: Cell::new(n + 1),
+            }
         }
     }
 
-
     for n in 0..10 {
-        let f = Foo{n: Cell::new(0)};
+        let f = Foo { n: Cell::new(0) };
         let it = it::repeat_n(f, n);
         // drain it
         let last = it.last();
         if n == 0 {
             assert_eq!(last, None);
         } else {
-            assert_eq!(last, Some(Foo{n: Cell::new(n - 1)}));
+            assert_eq!(
+                last,
+                Some(Foo {
+                    n: Cell::new(n - 1)
+                })
+            );
         }
     }
 }
@@ -285,16 +288,36 @@ fn tree_fold1() {
 #[test]
 fn exactly_one() {
     assert_eq!((0..10).filter(|&x| x == 2).exactly_one().unwrap(), 2);
-    assert!((0..10).filter(|&x| x > 1 && x < 4).exactly_one().unwrap_err().eq(2..4));
-    assert!((0..10).filter(|&x| x > 1 && x < 5).exactly_one().unwrap_err().eq(2..5));
-    assert!((0..10).filter(|&_| false).exactly_one().unwrap_err().eq(0..0));
+    assert!((0..10)
+        .filter(|&x| x > 1 && x < 4)
+        .exactly_one()
+        .unwrap_err()
+        .eq(2..4));
+    assert!((0..10)
+        .filter(|&x| x > 1 && x < 5)
+        .exactly_one()
+        .unwrap_err()
+        .eq(2..5));
+    assert!((0..10)
+        .filter(|&_| false)
+        .exactly_one()
+        .unwrap_err()
+        .eq(0..0));
 }
 
 #[test]
 fn at_most_one() {
     assert_eq!((0..10).filter(|&x| x == 2).at_most_one().unwrap(), Some(2));
-    assert!((0..10).filter(|&x| x > 1 && x < 4).at_most_one().unwrap_err().eq(2..4));
-    assert!((0..10).filter(|&x| x > 1 && x < 5).at_most_one().unwrap_err().eq(2..5));
+    assert!((0..10)
+        .filter(|&x| x > 1 && x < 4)
+        .at_most_one()
+        .unwrap_err()
+        .eq(2..4));
+    assert!((0..10)
+        .filter(|&x| x > 1 && x < 5)
+        .at_most_one()
+        .unwrap_err()
+        .eq(2..5));
     assert_eq!((0..10).filter(|&_| false).at_most_one().unwrap(), None);
 }
 
diff --git a/vendor/itertools/tests/test_std.rs b/vendor/itertools/tests/test_std.rs
index 77207d87e..732be7b7d 100644
--- a/vendor/itertools/tests/test_std.rs
+++ b/vendor/itertools/tests/test_std.rs
@@ -1,19 +1,25 @@
-use quickcheck as qc;
-use rand::{distributions::{Distribution, Standard}, Rng, SeedableRng, rngs::StdRng};
-use rand::{seq::SliceRandom, thread_rng};
-use std::{cmp::min, fmt::Debug, marker::PhantomData};
-use itertools as it;
-use crate::it::Itertools;
-use crate::it::ExactlyOneError;
-use crate::it::multizip;
-use crate::it::multipeek;
-use crate::it::peek_nth;
-use crate::it::free::rciter;
-use crate::it::free::put_back_n;
-use crate::it::FoldWhile;
+#![allow(unstable_name_collisions)]
+
 use crate::it::cloned;
+use crate::it::free::put_back_n;
+use crate::it::free::rciter;
 use crate::it::iproduct;
 use crate::it::izip;
+use crate::it::multipeek;
+use crate::it::multizip;
+use crate::it::peek_nth;
+use crate::it::ExactlyOneError;
+use crate::it::FoldWhile;
+use crate::it::Itertools;
+use itertools as it;
+use quickcheck as qc;
+use rand::{
+    distributions::{Distribution, Standard},
+    rngs::StdRng,
+    Rng, SeedableRng,
+};
+use rand::{seq::SliceRandom, thread_rng};
+use std::{cmp::min, fmt::Debug, marker::PhantomData};
 
 #[test]
 fn product3() {
@@ -27,9 +33,7 @@ fn product3() {
             }
         }
     }
-    for (_, _, _, _) in iproduct!(0..3, 0..2, 0..2, 0..3) {
-        /* test compiles */
-    }
+    for (_, _, _, _) in iproduct!(0..3, 0..2, 0..2, 0..3) { /* test compiles */ }
 }
 
 #[test]
@@ -62,9 +66,15 @@ fn duplicates_by() {
     let xs = ["aaa", "bbbbb", "aa", "ccc", "bbbb", "aaaaa", "cccc"];
     let ys = ["aa", "bbbb", "cccc"];
     it::assert_equal(ys.iter(), xs.iter().duplicates_by(|x| x[..2].to_string()));
-    it::assert_equal(ys.iter(), xs.iter().rev().duplicates_by(|x| x[..2].to_string()).rev());
+    it::assert_equal(
+        ys.iter(),
+        xs.iter().rev().duplicates_by(|x| x[..2].to_string()).rev(),
+    );
     let ys_rev = ["ccc", "aa", "bbbbb"];
-    it::assert_equal(ys_rev.iter(), xs.iter().duplicates_by(|x| x[..2].to_string()).rev());
+    it::assert_equal(
+        ys_rev.iter(),
+        xs.iter().duplicates_by(|x| x[..2].to_string()).rev(),
+    );
 }
 
 #[test]
@@ -86,7 +96,10 @@ fn duplicates() {
     let xs = vec![0, 1, 2, 1, 2];
     let ys = vec![1, 2];
     assert_eq!(ys, xs.iter().duplicates().cloned().collect_vec());
-    assert_eq!(ys, xs.iter().rev().duplicates().rev().cloned().collect_vec());
+    assert_eq!(
+        ys,
+        xs.iter().rev().duplicates().rev().cloned().collect_vec()
+    );
     let ys_rev = vec![2, 1];
     assert_eq!(ys_rev, xs.iter().duplicates().rev().cloned().collect_vec());
 }
@@ -96,9 +109,15 @@ fn unique_by() {
     let xs = ["aaa", "bbbbb", "aa", "ccc", "bbbb", "aaaaa", "cccc"];
     let ys = ["aaa", "bbbbb", "ccc"];
     it::assert_equal(ys.iter(), xs.iter().unique_by(|x| x[..2].to_string()));
-    it::assert_equal(ys.iter(), xs.iter().rev().unique_by(|x| x[..2].to_string()).rev());
+    it::assert_equal(
+        ys.iter(),
+        xs.iter().rev().unique_by(|x| x[..2].to_string()).rev(),
+    );
     let ys_rev = ["cccc", "aaaaa", "bbbb"];
-    it::assert_equal(ys_rev.iter(), xs.iter().unique_by(|x| x[..2].to_string()).rev());
+    it::assert_equal(
+        ys_rev.iter(),
+        xs.iter().unique_by(|x| x[..2].to_string()).rev(),
+    );
 }
 
 #[test]
@@ -149,13 +168,13 @@ fn dedup() {
 #[test]
 fn coalesce() {
     let data = vec![-1., -2., -3., 3., 1., 0., -1.];
-    let it = data.iter().cloned().coalesce(|x, y|
+    let it = data.iter().cloned().coalesce(|x, y| {
         if (x >= 0.) == (y >= 0.) {
             Ok(x + y)
         } else {
             Err((x, y))
         }
-    );
+    });
     itertools::assert_equal(it.clone(), vec![-6., 4., -1.]);
     assert_eq!(
         it.fold(vec![], |mut v, n| {
@@ -168,17 +187,37 @@ fn coalesce() {
 
 #[test]
 fn dedup_by() {
-    let xs = [(0, 0), (0, 1), (1, 1), (2, 1), (0, 2), (3, 1), (0, 3), (1, 3)];
+    let xs = [
+        (0, 0),
+        (0, 1),
+        (1, 1),
+        (2, 1),
+        (0, 2),
+        (3, 1),
+        (0, 3),
+        (1, 3),
+    ];
     let ys = [(0, 0), (0, 1), (0, 2), (3, 1), (0, 3)];
-    it::assert_equal(ys.iter(), xs.iter().dedup_by(|x, y| x.1==y.1));
+    it::assert_equal(ys.iter(), xs.iter().dedup_by(|x, y| x.1 == y.1));
     let xs = [(0, 1), (0, 2), (0, 3), (0, 4), (0, 5)];
     let ys = [(0, 1)];
-    it::assert_equal(ys.iter(), xs.iter().dedup_by(|x, y| x.0==y.0));
-
-    let xs = [(0, 0), (0, 1), (1, 1), (2, 1), (0, 2), (3, 1), (0, 3), (1, 3)];
+    it::assert_equal(ys.iter(), xs.iter().dedup_by(|x, y| x.0 == y.0));
+
+    let xs = [
+        (0, 0),
+        (0, 1),
+        (1, 1),
+        (2, 1),
+        (0, 2),
+        (3, 1),
+        (0, 3),
+        (1, 3),
+    ];
     let ys = [(0, 0), (0, 1), (0, 2), (3, 1), (0, 3)];
     let mut xs_d = Vec::new();
-    xs.iter().dedup_by(|x, y| x.1==y.1).fold((), |(), &elt| xs_d.push(elt));
+    xs.iter()
+        .dedup_by(|x, y| x.1 == y.1)
+        .fold((), |(), &elt| xs_d.push(elt));
     assert_eq!(&xs_d, &ys);
 }
 
@@ -195,18 +234,38 @@ fn dedup_with_count() {
     it::assert_equal(ys.iter().cloned(), xs.iter().dedup_with_count());
 }
 
-
 #[test]
 fn dedup_by_with_count() {
-    let xs = [(0, 0), (0, 1), (1, 1), (2, 1), (0, 2), (3, 1), (0, 3), (1, 3)];
-    let ys = [(1, &(0, 0)), (3, &(0, 1)), (1, &(0, 2)), (1, &(3, 1)), (2, &(0, 3))];
+    let xs = [
+        (0, 0),
+        (0, 1),
+        (1, 1),
+        (2, 1),
+        (0, 2),
+        (3, 1),
+        (0, 3),
+        (1, 3),
+    ];
+    let ys = [
+        (1, &(0, 0)),
+        (3, &(0, 1)),
+        (1, &(0, 2)),
+        (1, &(3, 1)),
+        (2, &(0, 3)),
+    ];
 
-    it::assert_equal(ys.iter().cloned(), xs.iter().dedup_by_with_count(|x, y| x.1==y.1));
+    it::assert_equal(
+        ys.iter().cloned(),
+        xs.iter().dedup_by_with_count(|x, y| x.1 == y.1),
+    );
 
     let xs = [(0, 1), (0, 2), (0, 3), (0, 4), (0, 5)];
-    let ys = [( 5, &(0, 1))];
+    let ys = [(5, &(0, 1))];
 
-    it::assert_equal(ys.iter().cloned(), xs.iter().dedup_by_with_count(|x, y| x.0==y.0));
+    it::assert_equal(
+        ys.iter().cloned(),
+        xs.iter().dedup_by_with_count(|x, y| x.0 == y.0),
+    );
 }
 
 #[test]
@@ -227,7 +286,7 @@ fn all_equal_value() {
     assert_eq!("AABBCCC".chars().all_equal_value(), Err(Some(('A', 'B'))));
     assert_eq!("AAAAAAA".chars().all_equal_value(), Ok('A'));
     {
-        let mut it = [1,2,3].iter().copied();
+        let mut it = [1, 2, 3].iter().copied();
         let result = it.all_equal_value();
         assert_eq!(result, Err(Some((1, 2))));
         let remaining = it.next();
@@ -256,7 +315,7 @@ fn test_put_back_n() {
 
 #[test]
 fn tee() {
-    let xs  = [0, 1, 2, 3];
+    let xs = [0, 1, 2, 3];
     let (mut t1, mut t2) = xs.iter().cloned().tee();
     assert_eq!(t1.next(), Some(0));
     assert_eq!(t2.next(), Some(0));
@@ -280,7 +339,6 @@ fn tee() {
     it::assert_equal(t1.zip(t2), xs.iter().cloned().zip(xs.iter().cloned()));
 }
 
-
 #[test]
 fn test_rciter() {
     let xs = [0, 1, 1, 1, 2, 1, 3, 5, 6];
@@ -304,19 +362,19 @@ fn test_rciter() {
 #[allow(deprecated)]
 #[test]
 fn trait_pointers() {
-    struct ByRef<'r, I: ?Sized>(&'r mut I) ;
+    struct ByRef<'r, I: ?Sized>(&'r mut I);
 
-    impl<'r, X, I: ?Sized> Iterator for ByRef<'r, I> where
-        I: 'r + Iterator<Item=X>
+    impl<'r, X, I: ?Sized> Iterator for ByRef<'r, I>
+    where
+        I: 'r + Iterator<Item = X>,
     {
         type Item = X;
-        fn next(&mut self) -> Option<Self::Item>
-        {
+        fn next(&mut self) -> Option<Self::Item> {
             self.0.next()
         }
     }
 
-    let mut it = Box::new(0..10) as Box<dyn Iterator<Item=i32>>;
+    let mut it = Box::new(0..10) as Box<dyn Iterator<Item = i32>>;
     assert_eq!(it.next(), Some(0));
 
     {
@@ -336,9 +394,16 @@ fn trait_pointers() {
 
 #[test]
 fn merge_by() {
-    let odd : Vec<(u32, &str)> = vec![(1, "hello"), (3, "world"), (5, "!")];
+    let odd: Vec<(u32, &str)> = vec![(1, "hello"), (3, "world"), (5, "!")];
     let even = vec![(2, "foo"), (4, "bar"), (6, "baz")];
-    let expected = vec![(1, "hello"), (2, "foo"), (3, "world"), (4, "bar"), (5, "!"), (6, "baz")];
+    let expected = vec![
+        (1, "hello"),
+        (2, "foo"),
+        (3, "world"),
+        (4, "bar"),
+        (5, "!"),
+        (6, "baz"),
+    ];
     let results = odd.iter().merge_by(even.iter(), |a, b| a.0 <= b.0);
     it::assert_equal(results, expected.iter());
 }
@@ -352,7 +417,7 @@ fn merge_by_btree() {
     let mut bt2 = BTreeMap::new();
     bt2.insert("foo", 2);
     bt2.insert("bar", 4);
-    let results = bt1.into_iter().merge_by(bt2.into_iter(), |a, b| a.0 <= b.0 );
+    let results = bt1.into_iter().merge_by(bt2.into_iter(), |a, b| a.0 <= b.0);
     let expected = vec![("bar", 4), ("foo", 2), ("hello", 1), ("world", 3)];
     it::assert_equal(results, expected.into_iter());
 }
@@ -394,19 +459,17 @@ fn kmerge_empty_size_hint() {
 #[test]
 fn join() {
     let many = [1, 2, 3];
-    let one  = [1];
+    let one = [1];
     let none: Vec<i32> = vec![];
 
     assert_eq!(many.iter().join(", "), "1, 2, 3");
-    assert_eq!( one.iter().join(", "), "1");
+    assert_eq!(one.iter().join(", "), "1");
     assert_eq!(none.iter().join(", "), "");
 }
 
 #[test]
 fn sorted_unstable_by() {
-    let sc = [3, 4, 1, 2].iter().cloned().sorted_by(|&a, &b| {
-        a.cmp(&b)
-    });
+    let sc = [3, 4, 1, 2].iter().cloned().sorted_by(|&a, &b| a.cmp(&b));
     it::assert_equal(sc, vec![1, 2, 3, 4]);
 
     let v = (0..5).sorted_unstable_by(|&a, &b| a.cmp(&b).reverse());
@@ -424,9 +487,7 @@ fn sorted_unstable_by_key() {
 
 #[test]
 fn sorted_by() {
-    let sc = [3, 4, 1, 2].iter().cloned().sorted_by(|&a, &b| {
-        a.cmp(&b)
-    });
+    let sc = [3, 4, 1, 2].iter().cloned().sorted_by(|&a, &b| a.cmp(&b));
     it::assert_equal(sc, vec![1, 2, 3, 4]);
 
     let v = (0..5).sorted_by(|&a, &b| a.cmp(&b).reverse());
@@ -459,11 +520,13 @@ struct RandIter<T: 'static + Clone + Send, R: 'static + Clone + Rng + SeedableRn
     idx: usize,
     len: usize,
     rng: R,
-    _t: PhantomData<T>
+    _t: PhantomData<T>,
 }
 
 impl<T: Clone + Send, R: Clone + Rng + SeedableRng + Send> Iterator for RandIter<T, R>
-where Standard: Distribution<T> {
+where
+    Standard: Distribution<T>,
+{
     type Item = T;
     fn next(&mut self) -> Option<T> {
         if self.idx == self.len {
@@ -481,7 +544,7 @@ impl<T: Clone + Send, R: Clone + Rng + SeedableRng + Send> qc::Arbitrary for Ran
             idx: 0,
             len: g.size(),
             rng: R::seed_from_u64(g.next_u64()),
-            _t : PhantomData{},
+            _t: PhantomData {},
         }
     }
 }
@@ -495,10 +558,7 @@ where
 {
     let j = i.clone();
     let k = k as usize;
-    it::assert_equal(
-        i.k_smallest(k),
-        j.sorted().take(k)
-    )
+    it::assert_equal(i.k_smallest(k), j.sorted().take(k))
 }
 
 macro_rules! generic_test {
@@ -550,7 +610,7 @@ fn sorted_by_cached_key() {
 
 #[test]
 fn test_multipeek() {
-    let nums = vec![1u8,2,3,4,5];
+    let nums = vec![1u8, 2, 3, 4, 5];
 
     let mp = multipeek(nums.iter().copied());
     assert_eq!(nums, mp.collect::<Vec<_>>());
@@ -591,7 +651,7 @@ fn test_multipeek_reset() {
 #[test]
 fn test_multipeek_peeking_next() {
     use crate::it::PeekingNext;
-    let nums = vec![1u8,2,3,4,5,6,7];
+    let nums = vec![1u8, 2, 3, 4, 5, 6, 7];
 
     let mut mp = multipeek(nums.iter().copied());
     assert_eq!(mp.peeking_next(|&x| x != 0), Some(1));
@@ -616,7 +676,7 @@ fn test_multipeek_peeking_next() {
 
 #[test]
 fn test_peek_nth() {
-    let nums = vec![1u8,2,3,4,5];
+    let nums = vec![1u8, 2, 3, 4, 5];
 
     let iter = peek_nth(nums.iter().copied());
     assert_eq!(nums, iter.collect::<Vec<_>>());
@@ -651,7 +711,7 @@ fn test_peek_nth() {
 #[test]
 fn test_peek_nth_peeking_next() {
     use it::PeekingNext;
-    let nums = vec![1u8,2,3,4,5,6,7];
+    let nums = vec![1u8, 2, 3, 4, 5, 6, 7];
     let mut iter = peek_nth(nums.iter().copied());
 
     assert_eq!(iter.peeking_next(|&x| x != 0), Some(1));
@@ -678,6 +738,35 @@ fn test_peek_nth_peeking_next() {
     assert_eq!(iter.peek(), None);
 }
 
+#[test]
+fn test_peek_nth_next_if() {
+    let nums = vec![1u8, 2, 3, 4, 5, 6, 7];
+    let mut iter = peek_nth(nums.iter().copied());
+
+    assert_eq!(iter.next_if(|&x| x != 0), Some(1));
+    assert_eq!(iter.next(), Some(2));
+
+    assert_eq!(iter.peek_nth(0), Some(&3));
+    assert_eq!(iter.peek_nth(1), Some(&4));
+    assert_eq!(iter.next_if_eq(&3), Some(3));
+    assert_eq!(iter.peek(), Some(&4));
+
+    assert_eq!(iter.next_if(|&x| x != 4), None);
+    assert_eq!(iter.next_if_eq(&4), Some(4));
+    assert_eq!(iter.peek_nth(0), Some(&5));
+    assert_eq!(iter.peek_nth(1), Some(&6));
+
+    assert_eq!(iter.next_if(|&x| x != 5), None);
+    assert_eq!(iter.peek(), Some(&5));
+
+    assert_eq!(iter.next_if(|&x| x % 2 == 1), Some(5));
+    assert_eq!(iter.next_if_eq(&6), Some(6));
+    assert_eq!(iter.peek_nth(0), Some(&7));
+    assert_eq!(iter.peek_nth(1), None);
+    assert_eq!(iter.next(), Some(7));
+    assert_eq!(iter.peek(), None);
+}
+
 #[test]
 fn pad_using() {
     it::assert_equal((0..0).pad_using(1, |_| 1), 1..2);
@@ -717,11 +806,11 @@ fn group_by() {
 
         for &idx in &indices[..] {
             let (key, text) = match idx {
-                 0 => ('A', "Aaa".chars()),
-                 1 => ('B', "Bbb".chars()),
-                 2 => ('C', "ccCc".chars()),
-                 3 => ('D', "DDDD".chars()),
-                 _ => unreachable!(),
+                0 => ('A', "Aaa".chars()),
+                1 => ('B', "Bbb".chars()),
+                2 => ('C', "ccCc".chars()),
+                3 => ('D', "DDDD".chars()),
+                _ => unreachable!(),
             };
             assert_eq!(key, subs[idx].0);
             it::assert_equal(&mut subs[idx].1, text);
@@ -746,9 +835,11 @@ fn group_by() {
     {
         let mut ntimes = 0;
         let text = "AABCCC";
-        for (_, sub) in &text.chars().group_by(|&x| { ntimes += 1; x}) {
-            for _ in sub {
-            }
+        for (_, sub) in &text.chars().group_by(|&x| {
+            ntimes += 1;
+            x
+        }) {
+            for _ in sub {}
         }
         assert_eq!(ntimes, text.len());
     }
@@ -756,8 +847,10 @@ fn group_by() {
     {
         let mut ntimes = 0;
         let text = "AABCCC";
-        for _ in &text.chars().group_by(|&x| { ntimes += 1; x}) {
-        }
+        for _ in &text.chars().group_by(|&x| {
+            ntimes += 1;
+            x
+        }) {}
         assert_eq!(ntimes, text.len());
     }
 
@@ -797,8 +890,7 @@ fn group_by_lazy_2() {
         if i < 2 {
             groups.push(group);
         } else if i < 4 {
-            for _ in group {
-            }
+            for _ in group {}
         } else {
             groups.push(group);
         }
@@ -810,7 +902,11 @@ fn group_by_lazy_2() {
     // use groups as chunks
     let data = vec![0, 0, 0, 1, 1, 0, 0, 2, 2, 3, 3];
     let mut i = 0;
-    let grouper = data.iter().group_by(move |_| { let k = i / 3; i += 1; k });
+    let grouper = data.iter().group_by(move |_| {
+        let k = i / 3;
+        i += 1;
+        k
+    });
     for (i, group) in &grouper {
         match i {
             0 => it::assert_equal(group, &[0, 0, 0]),
@@ -861,8 +957,8 @@ fn concat_empty() {
 
 #[test]
 fn concat_non_empty() {
-    let data = vec![vec![1,2,3], vec![4,5,6], vec![7,8,9]];
-    assert_eq!(data.into_iter().concat(), vec![1,2,3,4,5,6,7,8,9])
+    let data = vec![vec![1, 2, 3], vec![4, 5, 6], vec![7, 8, 9]];
+    assert_eq!(data.into_iter().concat(), vec![1, 2, 3, 4, 5, 6, 7, 8, 9])
 }
 
 #[test]
@@ -870,19 +966,20 @@ fn combinations() {
     assert!((1..3).combinations(5).next().is_none());
 
     let it = (1..3).combinations(2);
-    it::assert_equal(it, vec![
-        vec![1, 2],
-        ]);
+    it::assert_equal(it, vec![vec![1, 2]]);
 
     let it = (1..5).combinations(2);
-    it::assert_equal(it, vec![
-        vec![1, 2],
-        vec![1, 3],
-        vec![1, 4],
-        vec![2, 3],
-        vec![2, 4],
-        vec![3, 4],
-        ]);
+    it::assert_equal(
+        it,
+        vec![
+            vec![1, 2],
+            vec![1, 3],
+            vec![1, 4],
+            vec![2, 3],
+            vec![2, 4],
+            vec![3, 4],
+        ],
+    );
 
     it::assert_equal((0..0).tuple_combinations::<(_, _)>(), <Vec<_>>::new());
     it::assert_equal((0..1).tuple_combinations::<(_, _)>(), <Vec<_>>::new());
@@ -902,19 +999,128 @@ fn combinations_of_too_short() {
     }
 }
 
-
 #[test]
 fn combinations_zero() {
     it::assert_equal((1..3).combinations(0), vec![vec![]]);
     it::assert_equal((0..0).combinations(0), vec![vec![]]);
 }
 
+fn binomial(n: usize, k: usize) -> usize {
+    if k > n {
+        0
+    } else {
+        (n - k + 1..=n).product::<usize>() / (1..=k).product::<usize>()
+    }
+}
+
+#[test]
+fn combinations_range_count() {
+    for n in 0..=10 {
+        for k in 0..=10 {
+            let len = binomial(n, k);
+            let mut it = (0..n).combinations(k);
+            assert_eq!(len, it.clone().count());
+            assert_eq!(len, it.size_hint().0);
+            assert_eq!(Some(len), it.size_hint().1);
+            for count in (0..len).rev() {
+                let elem = it.next();
+                assert!(elem.is_some());
+                assert_eq!(count, it.clone().count());
+                assert_eq!(count, it.size_hint().0);
+                assert_eq!(Some(count), it.size_hint().1);
+            }
+            let should_be_none = it.next();
+            assert!(should_be_none.is_none());
+        }
+    }
+}
+
+#[test]
+fn combinations_inexact_size_hints() {
+    for k in 0..=10 {
+        let mut numbers = (0..18).filter(|i| i % 2 == 0); // 9 elements
+        let mut it = numbers.clone().combinations(k);
+        let real_n = numbers.clone().count();
+        let len = binomial(real_n, k);
+        assert_eq!(len, it.clone().count());
+
+        let mut nb_loaded = 0;
+        let sh = numbers.size_hint();
+        assert_eq!(binomial(sh.0 + nb_loaded, k), it.size_hint().0);
+        assert_eq!(sh.1.map(|n| binomial(n + nb_loaded, k)), it.size_hint().1);
+
+        for next_count in 1..=len {
+            let elem = it.next();
+            assert!(elem.is_some());
+            assert_eq!(len - next_count, it.clone().count());
+            if next_count == 1 {
+                // The very first time, the lazy buffer is prefilled.
+                nb_loaded = numbers.by_ref().take(k).count();
+            } else {
+                // Then it loads one item each time until exhausted.
+                let nb = numbers.next();
+                if nb.is_some() {
+                    nb_loaded += 1;
+                }
+            }
+            let sh = numbers.size_hint();
+            if next_count > real_n - k + 1 {
+                assert_eq!(0, sh.0);
+                assert_eq!(Some(0), sh.1);
+                assert_eq!(real_n, nb_loaded);
+                // Once it's fully loaded, size hints of `it` are exacts.
+            }
+            assert_eq!(binomial(sh.0 + nb_loaded, k) - next_count, it.size_hint().0);
+            assert_eq!(
+                sh.1.map(|n| binomial(n + nb_loaded, k) - next_count),
+                it.size_hint().1
+            );
+        }
+        let should_be_none = it.next();
+        assert!(should_be_none.is_none());
+    }
+}
+
 #[test]
 fn permutations_zero() {
     it::assert_equal((1..3).permutations(0), vec![vec![]]);
     it::assert_equal((0..0).permutations(0), vec![vec![]]);
 }
 
+#[test]
+fn permutations_range_count() {
+    for n in 0..=7 {
+        for k in 0..=7 {
+            let len = if k <= n { (n - k + 1..=n).product() } else { 0 };
+            let mut it = (0..n).permutations(k);
+            assert_eq!(len, it.clone().count());
+            assert_eq!(len, it.size_hint().0);
+            assert_eq!(Some(len), it.size_hint().1);
+            for count in (0..len).rev() {
+                let elem = it.next();
+                assert!(elem.is_some());
+                assert_eq!(count, it.clone().count());
+                assert_eq!(count, it.size_hint().0);
+                assert_eq!(Some(count), it.size_hint().1);
+            }
+            let should_be_none = it.next();
+            assert!(should_be_none.is_none());
+        }
+    }
+}
+
+#[test]
+fn permutations_overflowed_size_hints() {
+    let mut it = std::iter::repeat(()).permutations(2);
+    assert_eq!(it.size_hint().0, usize::MAX);
+    assert_eq!(it.size_hint().1, None);
+    for nb_generated in 1..=1000 {
+        it.next();
+        assert!(it.size_hint().0 >= usize::MAX - nb_generated);
+        assert_eq!(it.size_hint().1, None);
+    }
+}
+
 #[test]
 fn combinations_with_replacement() {
     // Pool smaller than n
@@ -932,15 +1138,9 @@ fn combinations_with_replacement() {
         ],
     );
     // Zero size
-    it::assert_equal(
-        (0..3).combinations_with_replacement(0),
-        vec![vec![]],
-    );
+    it::assert_equal((0..3).combinations_with_replacement(0), vec![vec![]]);
     // Zero size on empty pool
-    it::assert_equal(
-        (0..0).combinations_with_replacement(0),
-        vec![vec![]],
-    );
+    it::assert_equal((0..0).combinations_with_replacement(0), vec![vec![]]);
     // Empty pool
     it::assert_equal(
         (0..0).combinations_with_replacement(2),
@@ -948,21 +1148,70 @@ fn combinations_with_replacement() {
     );
 }
 
+#[test]
+fn combinations_with_replacement_range_count() {
+    for n in 0..=7 {
+        for k in 0..=7 {
+            let len = binomial(usize::saturating_sub(n + k, 1), k);
+            let mut it = (0..n).combinations_with_replacement(k);
+            assert_eq!(len, it.clone().count());
+            assert_eq!(len, it.size_hint().0);
+            assert_eq!(Some(len), it.size_hint().1);
+            for count in (0..len).rev() {
+                let elem = it.next();
+                assert!(elem.is_some());
+                assert_eq!(count, it.clone().count());
+                assert_eq!(count, it.size_hint().0);
+                assert_eq!(Some(count), it.size_hint().1);
+            }
+            let should_be_none = it.next();
+            assert!(should_be_none.is_none());
+        }
+    }
+}
+
 #[test]
 fn powerset() {
     it::assert_equal((0..0).powerset(), vec![vec![]]);
     it::assert_equal((0..1).powerset(), vec![vec![], vec![0]]);
-    it::assert_equal((0..2).powerset(), vec![vec![], vec![0], vec![1], vec![0, 1]]);
-    it::assert_equal((0..3).powerset(), vec![
-        vec![],
-        vec![0], vec![1], vec![2],
-        vec![0, 1], vec![0, 2], vec![1, 2],
-        vec![0, 1, 2]
-    ]);
+    it::assert_equal(
+        (0..2).powerset(),
+        vec![vec![], vec![0], vec![1], vec![0, 1]],
+    );
+    it::assert_equal(
+        (0..3).powerset(),
+        vec![
+            vec![],
+            vec![0],
+            vec![1],
+            vec![2],
+            vec![0, 1],
+            vec![0, 2],
+            vec![1, 2],
+            vec![0, 1, 2],
+        ],
+    );
 
     assert_eq!((0..4).powerset().count(), 1 << 4);
     assert_eq!((0..8).powerset().count(), 1 << 8);
     assert_eq!((0..16).powerset().count(), 1 << 16);
+
+    for n in 0..=10 {
+        let mut it = (0..n).powerset();
+        let len = 2_usize.pow(n);
+        assert_eq!(len, it.clone().count());
+        assert_eq!(len, it.size_hint().0);
+        assert_eq!(Some(len), it.size_hint().1);
+        for count in (0..len).rev() {
+            let elem = it.next();
+            assert!(elem.is_some());
+            assert_eq!(count, it.clone().count());
+            assert_eq!(count, it.size_hint().0);
+            assert_eq!(Some(count), it.size_hint().1);
+        }
+        let should_be_none = it.next();
+        assert!(should_be_none.is_none());
+    }
 }
 
 #[test]
@@ -987,8 +1236,7 @@ fn diff_longer() {
     let diff = it::diff_with(a.iter(), b_map, |a, b| *a == b);
 
     assert!(match diff {
-        Some(it::Diff::Longer(_, remaining)) =>
-            remaining.collect::<Vec<_>>() == vec![5, 6],
+        Some(it::Diff::Longer(_, remaining)) => remaining.collect::<Vec<_>>() == vec![5, 6],
         _ => false,
     });
 }
@@ -1056,8 +1304,8 @@ fn extrema_set() {
 
 #[test]
 fn minmax() {
-    use std::cmp::Ordering;
     use crate::it::MinMaxResult;
+    use std::cmp::Ordering;
 
     // A peculiar type: Equality compares both tuple items, but ordering only the
     // first item.  This is so we can check the stability property easily.
@@ -1076,7 +1324,10 @@ fn minmax() {
         }
     }
 
-    assert_eq!(None::<Option<u32>>.iter().minmax(), MinMaxResult::NoElements);
+    assert_eq!(
+        None::<Option<u32>>.iter().minmax(),
+        MinMaxResult::NoElements
+    );
 
     assert_eq!(Some(1u32).iter().minmax(), MinMaxResult::OneElement(&1));
 
@@ -1089,7 +1340,11 @@ fn minmax() {
     assert_eq!(min, &Val(2, 0));
     assert_eq!(max, &Val(0, 2));
 
-    let (min, max) = data.iter().minmax_by(|x, y| x.1.cmp(&y.1)).into_option().unwrap();
+    let (min, max) = data
+        .iter()
+        .minmax_by(|x, y| x.1.cmp(&y.1))
+        .into_option()
+        .unwrap();
     assert_eq!(min, &Val(2, 0));
     assert_eq!(max, &Val(0, 2));
 }
@@ -1112,8 +1367,9 @@ fn format() {
 
 #[test]
 fn while_some() {
-    let ns = (1..10).map(|x| if x % 5 != 0 { Some(x) } else { None })
-                    .while_some();
+    let ns = (1..10)
+        .map(|x| if x % 5 != 0 { Some(x) } else { None })
+        .while_some();
     it::assert_equal(ns, vec![1, 2, 3, 4]);
 }
 
@@ -1122,15 +1378,18 @@ fn while_some() {
 fn fold_while() {
     let mut iterations = 0;
     let vec = vec![1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
-    let sum = vec.into_iter().fold_while(0, |acc, item| {
-        iterations += 1;
-        let new_sum = acc + item;
-        if new_sum <= 20 {
-            FoldWhile::Continue(new_sum)
-        } else {
-            FoldWhile::Done(acc)
-        }
-    }).into_inner();
+    let sum = vec
+        .into_iter()
+        .fold_while(0, |acc, item| {
+            iterations += 1;
+            let new_sum = acc + item;
+            if new_sum <= 20 {
+                FoldWhile::Continue(new_sum)
+            } else {
+                FoldWhile::Done(acc)
+            }
+        })
+        .into_inner();
     assert_eq!(iterations, 6);
     assert_eq!(sum, 15);
 }
@@ -1157,7 +1416,11 @@ fn tree_fold1() {
         "0 1 x 2 3 x x 4 5 x 6 7 x x x 8 9 x 10 11 x x 12 13 x 14 15 x x x x",
     ];
     for (i, &s) in x.iter().enumerate() {
-        let expected = if s.is_empty() { None } else { Some(s.to_string()) };
+        let expected = if s.is_empty() {
+            None
+        } else {
+            Some(s.to_string())
+        };
         let num_strings = (0..i).map(|x| x.to_string());
         let actual = num_strings.tree_fold1(|a, b| format!("{} {} x", a, b));
         assert_eq!(actual, expected);
@@ -1169,16 +1432,52 @@ fn exactly_one_question_mark_syntax_works() {
     exactly_one_question_mark_return().unwrap_err();
 }
 
-fn exactly_one_question_mark_return() -> Result<(), ExactlyOneError<std::slice::Iter<'static, ()>>> {
+fn exactly_one_question_mark_return() -> Result<(), ExactlyOneError<std::slice::Iter<'static, ()>>>
+{
     [].iter().exactly_one()?;
     Ok(())
 }
 
 #[test]
 fn multiunzip() {
-    let (a, b, c): (Vec<_>, Vec<_>, Vec<_>) = [(0, 1, 2), (3, 4, 5), (6, 7, 8)].iter().cloned().multiunzip();
+    let (a, b, c): (Vec<_>, Vec<_>, Vec<_>) = [(0, 1, 2), (3, 4, 5), (6, 7, 8)]
+        .iter()
+        .cloned()
+        .multiunzip();
     assert_eq!((a, b, c), (vec![0, 3, 6], vec![1, 4, 7], vec![2, 5, 8]));
     let (): () = [(), (), ()].iter().cloned().multiunzip();
-    let t: (Vec<_>, Vec<_>, Vec<_>, Vec<_>, Vec<_>, Vec<_>, Vec<_>, Vec<_>, Vec<_>, Vec<_>, Vec<_>, Vec<_>) = [(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11)].iter().cloned().multiunzip();
-    assert_eq!(t, (vec![0], vec![1], vec![2], vec![3], vec![4], vec![5], vec![6], vec![7], vec![8], vec![9], vec![10], vec![11]));
+    let t: (
+        Vec<_>,
+        Vec<_>,
+        Vec<_>,
+        Vec<_>,
+        Vec<_>,
+        Vec<_>,
+        Vec<_>,
+        Vec<_>,
+        Vec<_>,
+        Vec<_>,
+        Vec<_>,
+        Vec<_>,
+    ) = [(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11)]
+        .iter()
+        .cloned()
+        .multiunzip();
+    assert_eq!(
+        t,
+        (
+            vec![0],
+            vec![1],
+            vec![2],
+            vec![3],
+            vec![4],
+            vec![5],
+            vec![6],
+            vec![7],
+            vec![8],
+            vec![9],
+            vec![10],
+            vec![11]
+        )
+    );
 }
diff --git a/vendor/itertools/tests/zip.rs b/vendor/itertools/tests/zip.rs
index 75157d34f..f2554d7a4 100644
--- a/vendor/itertools/tests/zip.rs
+++ b/vendor/itertools/tests/zip.rs
@@ -1,17 +1,18 @@
-use itertools::Itertools;
-use itertools::EitherOrBoth::{Both, Left, Right};
 use itertools::free::zip_eq;
 use itertools::multizip;
+use itertools::EitherOrBoth::{Both, Left, Right};
+use itertools::Itertools;
 
 #[test]
 fn zip_longest_fused() {
     let a = [Some(1), None, Some(3), Some(4)];
     let b = [1, 2, 3];
 
-    let unfused = a.iter().batching(|it| *it.next().unwrap())
+    let unfused = a
+        .iter()
+        .batching(|it| *it.next().unwrap())
         .zip_longest(b.iter().cloned());
-    itertools::assert_equal(unfused,
-                       vec![Both(1, 1), Right(2), Right(3)]);
+    itertools::assert_equal(unfused, vec![Both(1, 1), Right(2), Right(3)]);
 }
 
 #[test]
@@ -55,11 +56,9 @@ fn test_double_ended_zip() {
     assert_eq!(it.next_back(), None);
 }
 
-
 #[should_panic]
 #[test]
-fn zip_eq_panic1()
-{
+fn zip_eq_panic1() {
     let a = [1, 2];
     let b = [1, 2, 3];
 
@@ -68,8 +67,7 @@ fn zip_eq_panic1()
 
 #[should_panic]
 #[test]
-fn zip_eq_panic2()
-{
+fn zip_eq_panic2() {
     let a: [i32; 0] = [];
     let b = [1, 2, 3];
 
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