Do not create dangling &T in Weak<T>::drop

Author: CAD97

library/alloc/src/rc.rs

@@ -2042,7 +2042,7 @@ impl<T: ?Sized> Drop for Weak<T> {
         // the strong pointers have disappeared.
         if inner.weak() == 0 {
             unsafe {
-                Global.deallocate(self.ptr.cast(), Layout::for_value(self.ptr.as_ref()));
+                Global.deallocate(self.ptr.cast(), Layout::for_value_raw(self.ptr.as_ptr()));
             }
         }
     }

library/alloc/src/sync.rs

@@ -1927,7 +1927,7 @@ impl<T: ?Sized> Drop for Weak<T> {
 
         if inner.weak.fetch_sub(1, Release) == 1 {
             acquire!(inner.weak);
-            unsafe { Global.deallocate(self.ptr.cast(), Layout::for_value(self.ptr.as_ref())) }
+            unsafe { Global.deallocate(self.ptr.cast(), Layout::for_value_raw(self.ptr.as_ptr())) }
         }
     }
 }