Rollup merge of #100184 - Kixunil:stabilize_ptr_const_cast, r=m-ou-se

Stabilize ptr_const_cast

This stabilizes `ptr_const_cast` feature as was decided in a recent
[FCP](#92675 (comment))

Closes #92675

Author: Dylan-DPC

compiler/rustc_arena/src/lib.rs

@@ -19,7 +19,6 @@
 #![feature(rustc_attrs)]
 #![cfg_attr(test, feature(test))]
 #![feature(strict_provenance)]
-#![feature(ptr_const_cast)]
 
 use smallvec::SmallVec;
 

library/core/src/ptr/const_ptr.rs

@@ -95,8 +95,8 @@ impl<T: ?Sized> *const T {
     ///
     /// This is a bit safer than `as` because it wouldn't silently change the type if the code is
     /// refactored.
-    #[unstable(feature = "ptr_const_cast", issue = "92675")]
-    #[rustc_const_unstable(feature = "ptr_const_cast", issue = "92675")]
+    #[stable(feature = "ptr_const_cast", since = "1.65.0")]
+    #[rustc_const_stable(feature = "ptr_const_cast", since = "1.65.0")]
     pub const fn cast_mut(self) -> *mut T {
         self as _
     }

library/core/src/ptr/mut_ptr.rs

@@ -100,8 +100,8 @@ impl<T: ?Sized> *mut T {
     /// coercion.
     ///
     /// [`cast_mut`]: #method.cast_mut
-    #[unstable(feature = "ptr_const_cast", issue = "92675")]
-    #[rustc_const_unstable(feature = "ptr_const_cast", issue = "92675")]
+    #[stable(feature = "ptr_const_cast", since = "1.65.0")]
+    #[rustc_const_stable(feature = "ptr_const_cast", since = "1.65.0")]
     pub const fn cast_const(self) -> *const T {
         self as _
     }