From e8a05e201ee6cea12fe05e4271e91fd40c2fb235 Mon Sep 17 00:00:00 2001
From: Niko Matsakis <niko@alum.mit.edu>
Date: Wed, 8 Jan 2020 06:39:38 -0500
Subject: permit negative impls for non-auto traits

---
 src/libcore/clone.rs     | 5 +++++
 src/libcore/ops/deref.rs | 4 ++++
 2 files changed, 9 insertions(+)

(limited to 'src/libcore')

diff --git a/src/libcore/clone.rs b/src/libcore/clone.rs
index 9a412e57294..629c197e376 100644
--- a/src/libcore/clone.rs
+++ b/src/libcore/clone.rs
@@ -227,4 +227,9 @@ mod impls {
             *self
         }
     }
+
+    // Shared references can be cloned, but mutable references *cannot*!
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[cfg(not(bootstrap))]
+    impl<T: ?Sized> !Clone for &mut T {}
 }
diff --git a/src/libcore/ops/deref.rs b/src/libcore/ops/deref.rs
index 68244fdb381..e2deeb55661 100644
--- a/src/libcore/ops/deref.rs
+++ b/src/libcore/ops/deref.rs
@@ -81,6 +81,10 @@ impl<T: ?Sized> Deref for &T {
     }
 }
 
+#[cfg(not(bootstrap))]
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: ?Sized> !DerefMut for &T {}
+
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T: ?Sized> Deref for &mut T {
     type Target = T;
-- 
cgit 1.4.1-3-g733a5