library: Stabilize const_ptr_as_ref

Const-stabilizes:
- `NonNull::as_mut`

library/core/src/lib.rs

@@ -140,7 +140,6 @@
 #![feature(const_option_ext)]
 #![feature(const_pin)]
 #![feature(const_pointer_is_aligned)]
-#![feature(const_ptr_as_ref)]
 #![feature(const_ptr_is_null)]
 #![feature(const_ptr_sub_ptr)]
 #![feature(const_ptr_write)]

library/core/src/ptr/non_null.rs

@@ -394,7 +394,8 @@ pub const fn as_ptr(self) -> *mut T {
     ///
     /// [the module documentation]: crate::ptr#safety
     #[stable(feature = "nonnull", since = "1.25.0")]
-    #[rustc_const_unstable(feature = "const_ptr_as_ref", issue = "91822")]
+    #[cfg_attr(bootstrap, rustc_allow_const_fn_unstable(const_mut_refs))]
+    #[rustc_const_stable(feature = "const_ptr_as_ref", since = "CURRENT_RUSTC_VERSION")]
     #[must_use]
     #[inline(always)]
     pub const unsafe fn as_mut<'a>(&mut self) -> &'a mut T {

library/core/tests/lib.rs

@@ -30,7 +30,6 @@
 #![feature(const_option_ext)]
 #![feature(const_pin)]
 #![feature(const_pointer_is_aligned)]
-#![feature(const_ptr_as_ref)]
 #![feature(const_ptr_write)]
 #![feature(const_result)]
 #![feature(const_slice_from_ref)]