diff --git a/library/core/src/option.rs b/library/core/src/option.rs
index 5d34f5ca155..9f89bfd674a 100644
--- a/library/core/src/option.rs
+++ b/library/core/src/option.rs
@@ -433,7 +433,9 @@ pub fn unwrap_or_else<F: FnOnce() -> T>(self, f: F) -> T {
     ///
     /// # Safety
     ///
-    /// Undefined behavior if the value is [`None`].
+    /// Calling this method on [`None`] is *[undefined behavior]*.
+    ///
+    /// [undefined behavior]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html
     ///
     /// # Examples
     ///
diff --git a/library/core/src/result.rs b/library/core/src/result.rs
index a357750b92f..436f4bf20c7 100644
--- a/library/core/src/result.rs
+++ b/library/core/src/result.rs
@@ -827,7 +827,9 @@ pub fn unwrap_or_else<F: FnOnce(E) -> T>(self, op: F) -> T {
     ///
     /// # Safety
     ///
-    /// Undefined behavior if the value is an [`Err`].
+    /// Calling this method on an [`Err`] is *[undefined behavior]*.
+    ///
+    /// [undefined behavior]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html
     ///
     /// # Examples
     ///
@@ -859,7 +861,9 @@ pub unsafe fn unwrap_unchecked(self) -> T {
     ///
     /// # Safety
     ///
-    /// Undefined behavior if the value is an [`Ok`].
+    /// Calling this method on an [`Ok`] is *[undefined behavior]*.
+    ///
+    /// [undefined behavior]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html
     ///
     /// # Examples
     ///