Use raw_ref_op in A|Rc::as_ptr

src/liballoc/lib.rs

@@ -109,6 +109,7 @@
 #![feature(pattern)]
 #![feature(ptr_internals)]
 #![feature(ptr_offset_from)]
+#![feature(raw_ref_op)]
 #![feature(rustc_attrs)]
 #![feature(receiver_trait)]
 #![feature(min_specialization)]

src/liballoc/rc.rs

@@ -591,17 +591,13 @@ impl<T: ?Sized> Rc<T> {
     #[stable(feature = "weak_into_raw", since = "1.45.0")]
     pub fn as_ptr(this: &Self) -> *const T {
         let ptr: *mut RcBox<T> = NonNull::as_ptr(this.ptr);
-        let fake_ptr = ptr as *mut T;
 
         // SAFETY: This cannot go through Deref::deref.
         // Instead, we manually offset the pointer rather than manifesting a reference.
         // This is so that the returned pointer retains the same provenance as our pointer.
         // This is required so that e.g. `get_mut` can write through the pointer
         // after the Rc is recovered through `from_raw`.
-        unsafe {
-            let offset = data_offset(&(*ptr).value);
-            set_data_ptr(fake_ptr, (ptr as *mut u8).offset(offset))
-        }
+        unsafe { &raw const (*ptr).value }
     }
 
     /// Constructs an `Rc<T>` from a raw pointer.

src/liballoc/sync.rs

@@ -590,17 +590,13 @@ impl<T: ?Sized> Arc<T> {
     #[stable(feature = "weak_into_raw", since = "1.45.0")]
     pub fn as_ptr(this: &Self) -> *const T {
         let ptr: *mut ArcInner<T> = NonNull::as_ptr(this.ptr);
-        let fake_ptr = ptr as *mut T;
 
         // SAFETY: This cannot go through Deref::deref.
         // Instead, we manually offset the pointer rather than manifesting a reference.
         // This is so that the returned pointer retains the same provenance as our pointer.
         // This is required so that e.g. `get_mut` can write through the pointer
         // after the Arc is recovered through `from_raw`.
-        unsafe {
-            let offset = data_offset(&(*ptr).data);
-            set_data_ptr(fake_ptr, (ptr as *mut u8).offset(offset))
-        }
+        unsafe { &raw const (*ptr).data }
     }
 
     /// Constructs an `Arc<T>` from a raw pointer.