diff --git a/library/core/src/iter/traits/iterator.rs b/library/core/src/iter/traits/iterator.rs
index 29230b1665380..84da778c3b91c 100644
--- a/library/core/src/iter/traits/iterator.rs
+++ b/library/core/src/iter/traits/iterator.rs
@@ -236,6 +236,11 @@ pub trait Iterator {
     /// doing so, it keeps track of the current element. After [`None`] is
     /// returned, `last()` will then return the last element it saw.
     ///
+    /// # Panics
+    ///
+    /// This function might panic if the iterator has more than [`usize::MAX`]
+    /// elements.
+    ///
     /// # Examples
     ///
     /// ```