remove unnecessary CoerceUnsized impl

diff --git a/src/libcore/mem.rs b/src/libcore/mem.rs
index 1eec4def1bbffb751e343ead4a155865f97274eb..9efac3e8d4cb24b4ea942f2342e26a2932838bd6 100644 (file)
--- a/src/libcore/mem.rs
+++ b/src/libcore/mem.rs
@@ -1024,9 +1024,6 @@ fn deref_mut(&mut self) -> &mut Self::Target {
     }
 }
 
-#[unstable(feature = "coerce_unsized", issue = "27732")]
-impl<T: CoerceUnsized<U>, U> CoerceUnsized<ManuallyDrop<U>> for ManuallyDrop<T> {}
-
 /// A pinned reference.
 ///
 /// A pinned reference is a lot like a mutable reference, except that it is not