diff --git a/core/lib/Drupal/Component/PhpStorage/MTimeProtectedFileStorage.php b/core/lib/Drupal/Component/PhpStorage/MTimeProtectedFileStorage.php
index 26d8200c83e00ad15e7aa15d32c084137859c19c..077a40dd3895732d1c6a24fcb8b0a94d0ee80732 100644
--- a/core/lib/Drupal/Component/PhpStorage/MTimeProtectedFileStorage.php
+++ b/core/lib/Drupal/Component/PhpStorage/MTimeProtectedFileStorage.php
@@ -58,7 +58,8 @@ public function exists($name) {
    *
    * @param string $name
    *   The virtual file name. Can be a relative path.
-   * return string
+   *
+   * @return string|false
    *   The full path where the file is if it is valid, FALSE otherwise.
    */
   protected function checkFile($name) {