diff --git a/library/core/src/convert/mod.rs b/library/core/src/convert/mod.rs
index b30c8a4aeabdd..35a9cf2f5cd13 100644
--- a/library/core/src/convert/mod.rs
+++ b/library/core/src/convert/mod.rs
@@ -93,6 +93,8 @@ pub use num::FloatToInt;
 ///
 /// let iter = [Some(1), None, Some(3)].into_iter();
 /// let filtered = iter.filter_map(identity).collect::<Vec<_>>();
+/// // Equivalent, since Option implements IntoIterator:
+/// // let filtered = iter.flatten().collect::<Vec<_>>();
 /// assert_eq!(vec![1, 3], filtered);
 /// ```
 #[stable(feature = "convert_id", since = "1.33.0")]