diff --git a/library/core/src/iter/sources/from_fn.rs b/library/core/src/iter/sources/from_fn.rs
index 3cd3830471cfe..5f3d404d7dca2 100644
--- a/library/core/src/iter/sources/from_fn.rs
+++ b/library/core/src/iter/sources/from_fn.rs
@@ -3,6 +3,8 @@ use crate::fmt;
 /// Creates a new iterator where each iteration calls the provided closure
 /// `F: FnMut() -> Option<T>`.
 ///
+/// The iterator will yield the `T`s returned from the closure.
+///
 /// This allows creating a custom iterator with any behavior
 /// without using the more verbose syntax of creating a dedicated type
 /// and implementing the [`Iterator`] trait for it.
diff --git a/library/core/src/iter/sources/successors.rs b/library/core/src/iter/sources/successors.rs
index 36bc4035039e6..e14c9235e5562 100644
--- a/library/core/src/iter/sources/successors.rs
+++ b/library/core/src/iter/sources/successors.rs
@@ -5,6 +5,7 @@ use crate::iter::FusedIterator;
 ///
 /// The iterator starts with the given first item (if any)
 /// and calls the given `FnMut(&T) -> Option<T>` closure to compute each item’s successor.
+/// The iterator will yield the `T`s returned from the closure.
 ///
 /// ```
 /// use std::iter::successors;