From 3e07965244623ea709b842381f475178cf49879a Mon Sep 17 00:00:00 2001
From: Lukas Markeffsky <@>
Date: Fri, 23 Sep 2022 17:52:31 +0200
Subject: [PATCH] const stabilize `NonNull::as_ref`

---
 library/core/src/ptr/non_null.rs | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/library/core/src/ptr/non_null.rs b/library/core/src/ptr/non_null.rs
index b492d2f07bc1..ebed58ccf038 100644
--- a/library/core/src/ptr/non_null.rs
+++ b/library/core/src/ptr/non_null.rs
@@ -367,13 +367,14 @@ impl<T: ?Sized> NonNull<T> {
     ///
     /// [the module documentation]: crate::ptr#safety
     #[stable(feature = "nonnull", since = "1.25.0")]
-    #[rustc_const_unstable(feature = "const_ptr_as_ref", issue = "91822")]
+    #[rustc_const_stable(feature = "const_nonnull_as_ref", since = "CURRENT_RUSTC_VERSION")]
     #[must_use]
     #[inline(always)]
     pub const unsafe fn as_ref<'a>(&self) -> &'a T {
         // SAFETY: the caller must guarantee that `self` meets all the
         // requirements for a reference.
-        unsafe { &*self.as_ptr() }
+        // `cast_const` avoids a mutable raw pointer deref.
+        unsafe { &*self.as_ptr().cast_const() }
     }
 
     /// Returns a unique reference to the value. If the value may be uninitialized, [`as_uninit_mut`]