From 41434e001be222a7ce70faf3c5a23d97f462dfb8 Mon Sep 17 00:00:00 2001
From: Ralf Jung <post@ralfj.de>
Date: Fri, 16 Nov 2018 22:17:26 +0100
Subject: [PATCH 1/2] avoid shared ref in UnsafeCell::get

---
 src/libcore/cell.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/libcore/cell.rs b/src/libcore/cell.rs
index 9cf42eff219..b1ef15b4513 100644
--- a/src/libcore/cell.rs
+++ b/src/libcore/cell.rs
@@ -1509,7 +1509,7 @@ impl<T: ?Sized> UnsafeCell<T> {
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
     pub const fn get(&self) -> *mut T {
-        &self.value as *const T as *mut T
+        self as *const UnsafeCell<T> as *const T as *mut T
     }
 }
 

From 25d46f309130be1671d7e44d48e67b23f510bcdc Mon Sep 17 00:00:00 2001
From: Ralf Jung <post@ralfj.de>
Date: Sat, 17 Nov 2018 10:20:28 +0100
Subject: [PATCH 2/2] add comment explaining why what we do is legal

---
 src/libcore/cell.rs | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/libcore/cell.rs b/src/libcore/cell.rs
index b1ef15b4513..d8d51f53377 100644
--- a/src/libcore/cell.rs
+++ b/src/libcore/cell.rs
@@ -1509,6 +1509,8 @@ impl<T: ?Sized> UnsafeCell<T> {
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
     pub const fn get(&self) -> *mut T {
+        // We can just cast the pointer from `UnsafeCell<T>` to `T` because of
+        // #[repr(transparent)]
         self as *const UnsafeCell<T> as *const T as *mut T
     }
 }