Rollup merge of #122835 - compiler-errors:deref-pure, r=Nadrieril

Require `DerefMut` and `DerefPure` on `deref!()` patterns when appropriate

Waiting on the deref pattern syntax pr to merge

r? nadrieril

1 files changed, 4 insertions, 1 deletions

diff --git a/library/alloc/src/sync.rs b/library/alloc/src/sync.rs
index 7e3e2fb38b1..4dea27221b7 100644
--- a/library/alloc/src/sync.rs
+++ b/library/alloc/src/sync.rs
@@ -21,7 +21,7 @@ use core::marker::{PhantomData, Unsize};
 #[cfg(not(no_global_oom_handling))]
 use core::mem::size_of_val;
 use core::mem::{self, align_of_val_raw};
-use core::ops::{CoerceUnsized, Deref, DispatchFromDyn, Receiver};
+use core::ops::{CoerceUnsized, Deref, DerefPure, DispatchFromDyn, Receiver};
 use core::panic::{RefUnwindSafe, UnwindSafe};
 use core::pin::Pin;
 use core::ptr::{self, NonNull};
@@ -2107,6 +2107,9 @@ impl<T: ?Sized, A: Allocator> Deref for Arc<T, A> {
     }
 }
 
+#[unstable(feature = "deref_pure_trait", issue = "87121")]
+unsafe impl<T: ?Sized, A: Allocator> DerefPure for Arc<T, A> {}
+
 #[unstable(feature = "receiver_trait", issue = "none")]
 impl<T: ?Sized> Receiver for Arc<T> {}