diff --git a/src/libcore/char.rs b/src/libcore/char.rs
index 85e87c9172b..5f4ce9ebd84 100644
--- a/src/libcore/char.rs
+++ b/src/libcore/char.rs
@@ -107,7 +107,7 @@ pure fn is_digit(c: char) -> bool {
  *
  * # Safety note
  *
- * This function fails if `c` is not a valid char
+ * This function returns none if `c` is not a valid char
  *
  * # Return value
  *