Auto merge of #84864 - Mark-Simulacrum:stable-next, r=Mark-Simulacrum 1.52.0

[stable] 1.52.0 release

This includes the release notes (#84183) as well as cherry-picked commits from:

* [beta] revert PR #77885 #84710
* [beta] remove assert_matches #84759
* Revert PR 81473 to resolve (on beta) issues 81626 and 81658. #83171
* [beta] rustdoc revert deref recur #84868
*  Fix ICE of for-loop mut borrowck where no suggestions are available #83401

Additionally in "fresh work" we're also:

* reverting: directly expose copy and copy_nonoverlapping intrinsics #81238 to avoid https://github.com/rust-lang/rust/issues/84297 on 1.52

2 files changed, 10 insertions, 9 deletions

diff --git a/library/core/src/ptr/mod.rs b/library/core/src/ptr/mod.rs
index 3a27f01444b..fd24469bd3c 100644
--- a/library/core/src/ptr/mod.rs
+++ b/library/core/src/ptr/mod.rs
@@ -463,8 +463,7 @@ pub const unsafe fn swap_nonoverlapping<T>(x: *mut T, y: *mut T, count: usize) {
 }
 
 #[inline]
-#[rustc_const_unstable(feature = "const_swap", issue = "83163")]
-pub(crate) const unsafe fn swap_nonoverlapping_one<T>(x: *mut T, y: *mut T) {
+pub(crate) unsafe fn swap_nonoverlapping_one<T>(x: *mut T, y: *mut T) {
     // For types smaller than the block optimization below,
     // just swap directly to avoid pessimizing codegen.
     if mem::size_of::<T>() < 32 {
@@ -584,8 +583,7 @@ const unsafe fn swap_nonoverlapping_bytes(x: *mut u8, y: *mut u8, len: usize) {
 /// ```
 #[inline]
 #[stable(feature = "rust1", since = "1.0.0")]
-#[rustc_const_unstable(feature = "const_replace", issue = "83164")]
-pub const unsafe fn replace<T>(dst: *mut T, mut src: T) -> T {
+pub unsafe fn replace<T>(dst: *mut T, mut src: T) -> T {
     // SAFETY: the caller must guarantee that `dst` is valid to be
     // cast to a mutable reference (valid for writes, aligned, initialized),
     // and cannot overlap `src` since `dst` must point to a distinct
@@ -898,14 +896,18 @@ pub const unsafe fn read_unaligned<T>(src: *const T) -> T {
 /// ```
 #[inline]
 #[stable(feature = "rust1", since = "1.0.0")]
-#[rustc_const_unstable(feature = "const_ptr_write", issue = "none")]
-pub const unsafe fn write<T>(dst: *mut T, src: T) {
+pub unsafe fn write<T>(dst: *mut T, src: T) {
+    // We are calling the intrinsics directly to avoid function calls in the generated code
+    // as `intrinsics::copy_nonoverlapping` is a wrapper function.
+    extern "rust-intrinsic" {
+        fn copy_nonoverlapping<T>(src: *const T, dst: *mut T, count: usize);
+    }
+
     // SAFETY: the caller must guarantee that `dst` is valid for writes.
     // `dst` cannot overlap `src` because the caller has mutable access
     // to `dst` while `src` is owned by this function.
     unsafe {
         copy_nonoverlapping(&src as *const T, dst, 1);
-        // We are calling the intrinsic directly to avoid function calls in the generated code.
         intrinsics::forget(src);
     }
 }
diff --git a/library/core/src/ptr/mut_ptr.rs b/library/core/src/ptr/mut_ptr.rs
index fa09cf85435..a9de2333bc0 100644
--- a/library/core/src/ptr/mut_ptr.rs
+++ b/library/core/src/ptr/mut_ptr.rs
@@ -1013,9 +1013,8 @@ impl<T: ?Sized> *mut T {
     ///
     /// [`ptr::write`]: crate::ptr::write()
     #[stable(feature = "pointer_methods", since = "1.26.0")]
-    #[rustc_const_unstable(feature = "const_ptr_write", issue = "none")]
     #[inline]
-    pub const unsafe fn write(self, val: T)
+    pub unsafe fn write(self, val: T)
     where
         T: Sized,
     {