Merging upstream version 1.71.1+dfsg1.

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

5 files changed, 22 insertions, 27 deletions

diff --git a/library/alloc/src/vec/drain.rs b/library/alloc/src/vec/drain.rs
index 2b1a787cc..f0b63759a 100644
--- a/library/alloc/src/vec/drain.rs
+++ b/library/alloc/src/vec/drain.rs
@@ -16,7 +16,7 @@ use super::Vec;
 ///
 /// ```
 /// let mut v = vec![0, 1, 2];
-/// let iter: std::vec::Drain<_> = v.drain(..);
+/// let iter: std::vec::Drain<'_, _> = v.drain(..);
 /// ```
 #[stable(feature = "drain", since = "1.6.0")]
 pub struct Drain<
@@ -112,9 +112,7 @@ impl<'a, T, A: Allocator> Drain<'a, T, A> {
             let unyielded_ptr = this.iter.as_slice().as_ptr();
 
             // ZSTs have no identity, so we don't need to move them around.
-            let needs_move = mem::size_of::<T>() != 0;
-
-            if needs_move {
+            if !T::IS_ZST {
                 let start_ptr = source_vec.as_mut_ptr().add(start);
 
                 // memmove back unyielded elements
@@ -197,7 +195,7 @@ impl<T, A: Allocator> Drop for Drain<'_, T, A> {
             }
         }
 
-        let iter = mem::replace(&mut self.iter, (&mut []).iter());
+        let iter = mem::take(&mut self.iter);
         let drop_len = iter.len();
 
         let mut vec = self.vec;
diff --git a/library/alloc/src/vec/drain_filter.rs b/library/alloc/src/vec/drain_filter.rs
index 8c03f1692..21b090234 100644
--- a/library/alloc/src/vec/drain_filter.rs
+++ b/library/alloc/src/vec/drain_filter.rs
@@ -1,5 +1,5 @@
 use crate::alloc::{Allocator, Global};
-use core::mem::{self, ManuallyDrop};
+use core::mem::{ManuallyDrop, SizedTypeProperties};
 use core::ptr;
 use core::slice;
 
@@ -16,7 +16,7 @@ use super::Vec;
 /// #![feature(drain_filter)]
 ///
 /// let mut v = vec![0, 1, 2];
-/// let iter: std::vec::DrainFilter<_, _> = v.drain_filter(|x| *x % 2 == 0);
+/// let iter: std::vec::DrainFilter<'_, _, _> = v.drain_filter(|x| *x % 2 == 0);
 /// ```
 #[unstable(feature = "drain_filter", reason = "recently added", issue = "43244")]
 #[derive(Debug)]
@@ -96,9 +96,7 @@ where
 
         unsafe {
             // ZSTs have no identity, so we don't need to move them around.
-            let needs_move = mem::size_of::<T>() != 0;
-
-            if needs_move && this.idx < this.old_len && this.del > 0 {
+            if !T::IS_ZST && this.idx < this.old_len && this.del > 0 {
                 let ptr = this.vec.as_mut_ptr();
                 let src = ptr.add(this.idx);
                 let dst = src.sub(this.del);
diff --git a/library/alloc/src/vec/in_place_collect.rs b/library/alloc/src/vec/in_place_collect.rs
index 87d61deb1..5ecd04799 100644
--- a/library/alloc/src/vec/in_place_collect.rs
+++ b/library/alloc/src/vec/in_place_collect.rs
@@ -178,7 +178,8 @@ where
             )
         };
 
-        let len = SpecInPlaceCollect::collect_in_place(&mut iterator, dst_buf, dst_end);
+        // SAFETY: `dst_buf` and `dst_end` are the start and end of the buffer.
+        let len = unsafe { SpecInPlaceCollect::collect_in_place(&mut iterator, dst_buf, dst_end) };
 
         let src = unsafe { iterator.as_inner().as_into_iter() };
         // check if SourceIter contract was upheld
@@ -201,7 +202,7 @@ where
         //
         // Note: This access to the source wouldn't be allowed by the TrustedRandomIteratorNoCoerce
         // contract (used by SpecInPlaceCollect below). But see the "O(1) collect" section in the
-        // module documenttation why this is ok anyway.
+        // module documentation why this is ok anyway.
         let dst_guard = InPlaceDstBufDrop { ptr: dst_buf, len, cap };
         src.forget_allocation_drop_remaining();
         mem::forget(dst_guard);
@@ -239,7 +240,7 @@ trait SpecInPlaceCollect<T, I>: Iterator<Item = T> {
     /// `Iterator::__iterator_get_unchecked` calls with a `TrustedRandomAccessNoCoerce` bound
     /// on `I` which means the caller of this method must take the safety conditions
     /// of that trait into consideration.
-    fn collect_in_place(&mut self, dst: *mut T, end: *const T) -> usize;
+    unsafe fn collect_in_place(&mut self, dst: *mut T, end: *const T) -> usize;
 }
 
 impl<T, I> SpecInPlaceCollect<T, I> for I
@@ -247,7 +248,7 @@ where
     I: Iterator<Item = T>,
 {
     #[inline]
-    default fn collect_in_place(&mut self, dst_buf: *mut T, end: *const T) -> usize {
+    default unsafe fn collect_in_place(&mut self, dst_buf: *mut T, end: *const T) -> usize {
         // use try-fold since
         // - it vectorizes better for some iterator adapters
         // - unlike most internal iteration methods, it only takes a &mut self
@@ -265,7 +266,7 @@ where
     I: Iterator<Item = T> + TrustedRandomAccessNoCoerce,
 {
     #[inline]
-    fn collect_in_place(&mut self, dst_buf: *mut T, end: *const T) -> usize {
+    unsafe fn collect_in_place(&mut self, dst_buf: *mut T, end: *const T) -> usize {
         let len = self.size();
         let mut drop_guard = InPlaceDrop { inner: dst_buf, dst: dst_buf };
         for i in 0..len {
diff --git a/library/alloc/src/vec/mod.rs b/library/alloc/src/vec/mod.rs
index 3736a6e0b..47661a3d3 100644
--- a/library/alloc/src/vec/mod.rs
+++ b/library/alloc/src/vec/mod.rs
@@ -646,14 +646,14 @@ impl<T, A: Allocator> Vec<T, A> {
     ///
     /// // The vector contains no items, even though it has capacity for more
     /// assert_eq!(vec.len(), 0);
-    /// assert_eq!(vec.capacity(), 10);
+    /// assert!(vec.capacity() >= 10);
     ///
     /// // These are all done without reallocating...
     /// for i in 0..10 {
     ///     vec.push(i);
     /// }
     /// assert_eq!(vec.len(), 10);
-    /// assert_eq!(vec.capacity(), 10);
+    /// assert!(vec.capacity() >= 10);
     ///
     /// // ...but this may make the vector reallocate
     /// vec.push(11);
@@ -877,7 +877,7 @@ impl<T, A: Allocator> Vec<T, A> {
     /// ```
     /// let mut vec: Vec<i32> = Vec::with_capacity(10);
     /// vec.push(42);
-    /// assert_eq!(vec.capacity(), 10);
+    /// assert!(vec.capacity() >= 10);
     /// ```
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
@@ -1028,7 +1028,7 @@ impl<T, A: Allocator> Vec<T, A> {
     /// ```
     /// let mut vec = Vec::with_capacity(10);
     /// vec.extend([1, 2, 3]);
-    /// assert_eq!(vec.capacity(), 10);
+    /// assert!(vec.capacity() >= 10);
     /// vec.shrink_to_fit();
     /// assert!(vec.capacity() >= 3);
     /// ```
@@ -1055,7 +1055,7 @@ impl<T, A: Allocator> Vec<T, A> {
     /// ```
     /// let mut vec = Vec::with_capacity(10);
     /// vec.extend([1, 2, 3]);
-    /// assert_eq!(vec.capacity(), 10);
+    /// assert!(vec.capacity() >= 10);
     /// vec.shrink_to(4);
     /// assert!(vec.capacity() >= 4);
     /// vec.shrink_to(0);
@@ -1090,7 +1090,7 @@ impl<T, A: Allocator> Vec<T, A> {
     /// let mut vec = Vec::with_capacity(10);
     /// vec.extend([1, 2, 3]);
     ///
-    /// assert_eq!(vec.capacity(), 10);
+    /// assert!(vec.capacity() >= 10);
     /// let slice = vec.into_boxed_slice();
     /// assert_eq!(slice.into_vec().capacity(), 3);
     /// ```
@@ -2662,7 +2662,6 @@ impl<T: Clone, A: Allocator + Clone> Clone for Vec<T, A> {
 /// as required by the `core::borrow::Borrow` implementation.
 ///
 /// ```
-/// #![feature(build_hasher_simple_hash_one)]
 /// use std::hash::BuildHasher;
 ///
 /// let b = std::collections::hash_map::RandomState::new();
@@ -3022,8 +3021,7 @@ unsafe impl<#[may_dangle] T, A: Allocator> Drop for Vec<T, A> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-#[rustc_const_unstable(feature = "const_default_impls", issue = "87864")]
-impl<T> const Default for Vec<T> {
+impl<T> Default for Vec<T> {
     /// Creates an empty `Vec<T>`.
     ///
     /// The vector will not allocate until elements are pushed onto it.
@@ -3143,8 +3141,8 @@ where
     ///
     /// ```
     /// # use std::borrow::Cow;
-    /// let o: Cow<[i32]> = Cow::Owned(vec![1, 2, 3]);
-    /// let b: Cow<[i32]> = Cow::Borrowed(&[1, 2, 3]);
+    /// let o: Cow<'_, [i32]> = Cow::Owned(vec![1, 2, 3]);
+    /// let b: Cow<'_, [i32]> = Cow::Borrowed(&[1, 2, 3]);
     /// assert_eq!(Vec::from(o), Vec::from(b));
     /// ```
     fn from(s: Cow<'a, [T]>) -> Vec<T> {
diff --git a/library/alloc/src/vec/splice.rs b/library/alloc/src/vec/splice.rs
index 1861147fe..852fdcc3f 100644
--- a/library/alloc/src/vec/splice.rs
+++ b/library/alloc/src/vec/splice.rs
@@ -14,7 +14,7 @@ use super::{Drain, Vec};
 /// ```
 /// let mut v = vec![0, 1, 2];
 /// let new = [7, 8];
-/// let iter: std::vec::Splice<_> = v.splice(1.., new);
+/// let iter: std::vec::Splice<'_, _> = v.splice(1.., new);
 /// ```
 #[derive(Debug)]
 #[stable(feature = "vec_splice", since = "1.21.0")]