From 753dac16abd16411e1833b35ba82cabac6997cec Mon Sep 17 00:00:00 2001
From: inquisitivecrystal
 <22333129+inquisitivecrystal@users.noreply.github.com>
Date: Tue, 31 Aug 2021 14:44:13 -0700
Subject: [PATCH 1/2] Stabilize `UnsafeCell::raw_get()`

---
 library/core/src/cell.rs | 5 ++---
 library/std/src/lib.rs   | 1 -
 2 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/library/core/src/cell.rs b/library/core/src/cell.rs
index 85b43f4884760..2adf6a549e641 100644
--- a/library/core/src/cell.rs
+++ b/library/core/src/cell.rs
@@ -1921,7 +1921,7 @@ impl<T: ?Sized> UnsafeCell<T> {
     }
 
     /// Gets a mutable pointer to the wrapped value.
-    /// The difference to [`get`] is that this function accepts a raw pointer,
+    /// The difference from [`get`] is that this function accepts a raw pointer,
     /// which is useful to avoid the creation of temporary references.
     ///
     /// The result can be cast to a pointer of any kind.
@@ -1937,7 +1937,6 @@ impl<T: ?Sized> UnsafeCell<T> {
     /// calling `get` would require creating a reference to uninitialized data:
     ///
     /// ```
-    /// #![feature(unsafe_cell_raw_get)]
     /// use std::cell::UnsafeCell;
     /// use std::mem::MaybeUninit;
     ///
@@ -1948,7 +1947,7 @@ impl<T: ?Sized> UnsafeCell<T> {
     /// assert_eq!(uc.into_inner(), 5);
     /// ```
     #[inline(always)]
-    #[unstable(feature = "unsafe_cell_raw_get", issue = "66358")]
+    #[stable(feature = "unsafe_cell_raw_get", since = "1.56.0")]
     pub const fn raw_get(this: *const Self) -> *mut T {
         // We can just cast the pointer from `UnsafeCell<T>` to `T` because of
         // #[repr(transparent)]. This exploits libstd's special status, there is
diff --git a/library/std/src/lib.rs b/library/std/src/lib.rs
index 028a066b5a130..43c7ec5fad33a 100644
--- a/library/std/src/lib.rs
+++ b/library/std/src/lib.rs
@@ -331,7 +331,6 @@
 #![feature(try_reserve)]
 #![feature(try_reserve_kind)]
 #![feature(unboxed_closures)]
-#![feature(unsafe_cell_raw_get)]
 #![feature(unwrap_infallible)]
 #![feature(vec_into_raw_parts)]
 #![feature(vec_spare_capacity)]

From 227e004d3fda91b72eef2b5e064dcbf3647dc68e Mon Sep 17 00:00:00 2001
From: inquisitivecrystal
 <22333129+inquisitivecrystal@users.noreply.github.com>
Date: Tue, 31 Aug 2021 16:32:01 -0700
Subject: [PATCH 2/2] Add a few tests for `UnsafeCell`

---
 library/core/tests/cell.rs | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/library/core/tests/cell.rs b/library/core/tests/cell.rs
index 77517879dd250..85a006c5d5bef 100644
--- a/library/core/tests/cell.rs
+++ b/library/core/tests/cell.rs
@@ -2,6 +2,38 @@ use core::cell::*;
 use core::default::Default;
 use std::mem::drop;
 
+#[test]
+fn smoketest_unsafe_cell() {
+    let mut x = UnsafeCell::new(10);
+    let ref_mut = &mut x;
+    unsafe {
+        // The asserts are repeated in order to ensure that `get()`
+        // is non-mutating.
+        assert_eq!(*ref_mut.get(), 10);
+        assert_eq!(*ref_mut.get(), 10);
+        *ref_mut.get_mut() += 5;
+        assert_eq!(*ref_mut.get(), 15);
+        assert_eq!(*ref_mut.get(), 15);
+        assert_eq!(x.into_inner(), 15);
+    }
+}
+
+#[test]
+fn unsafe_cell_raw_get() {
+    let x = UnsafeCell::new(10);
+    let ptr = &x as *const UnsafeCell<i32>;
+    unsafe {
+        // The asserts are repeated in order to ensure that `raw_get()`
+        // is non-mutating.
+        assert_eq!(*UnsafeCell::raw_get(ptr), 10);
+        assert_eq!(*UnsafeCell::raw_get(ptr), 10);
+        *UnsafeCell::raw_get(ptr) += 5;
+        assert_eq!(*UnsafeCell::raw_get(ptr), 15);
+        assert_eq!(*UnsafeCell::raw_get(ptr), 15);
+        assert_eq!(x.into_inner(), 15);
+    }
+}
+
 #[test]
 fn smoketest_cell() {
     let x = Cell::new(10);