diff --git a/library/core/src/ptr/mod.rs b/library/core/src/ptr/mod.rs
index 7245feed672..6b96c6929a6 100644
--- a/library/core/src/ptr/mod.rs
+++ b/library/core/src/ptr/mod.rs
@@ -442,7 +442,7 @@ mod mut_ptr;
 ///
 /// ```
 /// # struct Foo { x: i32 }
-/// fn drop_in_place(to_drop: *mut Foo) {
+/// unsafe fn drop_in_place(to_drop: *mut Foo) {
 ///     let mut value = &mut *to_drop;
 ///     // ... drop the fields of `value` ...
 /// }