Auto merge of #92070 - rukai:replace_vec_into_iter_with_array_into_iter, r=Mark-Simulacrum

Replace usages of vec![].into_iter with [].into_iter

`[].into_iter` is idiomatic over `vec![].into_iter` because its simpler and faster (unless the vec is optimized away in which case it would be the same)

So we should change all the implementation, documentation and tests to use it.

I skipped:
* `src/tools` - Those are copied in from upstream
* `src/test/ui` - Hard to tell if `vec![].into_iter` was used intentionally or not here and not much benefit to changing it.
*  any case where `vec![].into_iter` was used because we specifically needed a `Vec::IntoIter<T>`
*  any case where it looked like we were intentionally using `vec![].into_iter` to test it.

2 files changed, 10 insertions, 10 deletions

diff --git a/library/alloc/src/collections/btree/map/tests.rs b/library/alloc/src/collections/btree/map/tests.rs
index c95aeeaa605..b39b5409ae4 100644
--- a/library/alloc/src/collections/btree/map/tests.rs
+++ b/library/alloc/src/collections/btree/map/tests.rs
@@ -728,7 +728,7 @@ fn test_range_large() {
 #[test]
 fn test_range_inclusive_max_value() {
     let max = usize::MAX;
-    let map: BTreeMap<_, _> = vec![(max, 0)].into_iter().collect();
+    let map: BTreeMap<_, _> = [(max, 0)].into_iter().collect();
 
     assert_eq!(map.range(max..=max).collect::<Vec<_>>(), &[(&max, &0)]);
 }
@@ -2128,7 +2128,7 @@ fn test_into_iter_drop_leak_height_1() {
 
 #[test]
 fn test_into_keys() {
-    let vec = vec![(1, 'a'), (2, 'b'), (3, 'c')];
+    let vec = [(1, 'a'), (2, 'b'), (3, 'c')];
     let map: BTreeMap<_, _> = vec.into_iter().collect();
     let keys: Vec<_> = map.into_keys().collect();
 
diff --git a/library/alloc/src/collections/vec_deque/mod.rs b/library/alloc/src/collections/vec_deque/mod.rs
index 075becfb7d1..1259c53bfab 100644
--- a/library/alloc/src/collections/vec_deque/mod.rs
+++ b/library/alloc/src/collections/vec_deque/mod.rs
@@ -669,7 +669,7 @@ impl<T, A: Allocator> VecDeque<T, A> {
     /// ```
     /// use std::collections::VecDeque;
     ///
-    /// let mut buf: VecDeque<i32> = vec![1].into_iter().collect();
+    /// let mut buf: VecDeque<i32> = [1].into_iter().collect();
     /// buf.reserve_exact(10);
     /// assert!(buf.capacity() >= 11);
     /// ```
@@ -692,7 +692,7 @@ impl<T, A: Allocator> VecDeque<T, A> {
     /// ```
     /// use std::collections::VecDeque;
     ///
-    /// let mut buf: VecDeque<i32> = vec![1].into_iter().collect();
+    /// let mut buf: VecDeque<i32> = [1].into_iter().collect();
     /// buf.reserve(10);
     /// assert!(buf.capacity() >= 11);
     /// ```
@@ -1153,7 +1153,7 @@ impl<T, A: Allocator> VecDeque<T, A> {
     /// ```
     /// use std::collections::VecDeque;
     ///
-    /// let v: VecDeque<_> = vec![1, 2, 3].into_iter().collect();
+    /// let v: VecDeque<_> = [1, 2, 3].into_iter().collect();
     /// let range = v.range(2..).copied().collect::<VecDeque<_>>();
     /// assert_eq!(range, [3]);
     ///
@@ -1188,7 +1188,7 @@ impl<T, A: Allocator> VecDeque<T, A> {
     /// ```
     /// use std::collections::VecDeque;
     ///
-    /// let mut v: VecDeque<_> = vec![1, 2, 3].into_iter().collect();
+    /// let mut v: VecDeque<_> = [1, 2, 3].into_iter().collect();
     /// for v in v.range_mut(2..) {
     ///   *v *= 2;
     /// }
@@ -1235,7 +1235,7 @@ impl<T, A: Allocator> VecDeque<T, A> {
     /// ```
     /// use std::collections::VecDeque;
     ///
-    /// let mut v: VecDeque<_> = vec![1, 2, 3].into_iter().collect();
+    /// let mut v: VecDeque<_> = [1, 2, 3].into_iter().collect();
     /// let drained = v.drain(2..).collect::<VecDeque<_>>();
     /// assert_eq!(drained, [3]);
     /// assert_eq!(v, [1, 2]);
@@ -2025,7 +2025,7 @@ impl<T, A: Allocator> VecDeque<T, A> {
     /// ```
     /// use std::collections::VecDeque;
     ///
-    /// let mut buf: VecDeque<_> = vec![1, 2, 3].into_iter().collect();
+    /// let mut buf: VecDeque<_> = [1, 2, 3].into_iter().collect();
     /// let buf2 = buf.split_off(1);
     /// assert_eq!(buf, [1]);
     /// assert_eq!(buf2, [2, 3]);
@@ -2091,8 +2091,8 @@ impl<T, A: Allocator> VecDeque<T, A> {
     /// ```
     /// use std::collections::VecDeque;
     ///
-    /// let mut buf: VecDeque<_> = vec![1, 2].into_iter().collect();
-    /// let mut buf2: VecDeque<_> = vec![3, 4].into_iter().collect();
+    /// let mut buf: VecDeque<_> = [1, 2].into_iter().collect();
+    /// let mut buf2: VecDeque<_> = [3, 4].into_iter().collect();
     /// buf.append(&mut buf2);
     /// assert_eq!(buf, [1, 2, 3, 4]);
     /// assert_eq!(buf2, []);