Rollup merge of rust-lang#30735 - jonastepe:nomicon_vec_dealloc_point…

…er_type, r=steveklabnik

heap::deallocate expects a *mut u8, but here a *mut T is given as the type of the argument. This would not compile. The final code is correct, however.

src/doc/nomicon/vec-dealloc.md

@@ -21,7 +21,7 @@ impl<T> Drop for Vec<T> {
             let elem_size = mem::size_of::<T>();
             let num_bytes = elem_size * self.cap;
             unsafe {
-                heap::deallocate(*self.ptr, num_bytes, align);
+                heap::deallocate(*self.ptr as *mut _, num_bytes, align);
             }
         }
     }