diff --git a/library/core/src/marker.rs b/library/core/src/marker.rs
index 85e2e3830a5..f113f939230 100644
--- a/library/core/src/marker.rs
+++ b/library/core/src/marker.rs
@@ -323,6 +323,7 @@ pub trait StructuralEq {
 /// ```
 /// # #![allow(dead_code)]
 /// # struct PointList;
+/// #[derive(Copy, Clone)]
 /// struct PointListWrapper<'a> {
 ///     point_list_ref: &'a PointList,
 /// }