diff --git a/src/wp-includes/cache.php b/src/wp-includes/cache.php
index e7fe7b87a8..a3b5f79153 100644
--- a/src/wp-includes/cache.php
+++ b/src/wp-includes/cache.php
@@ -144,7 +144,7 @@ function wp_cache_set_multiple( array $data, $group = '', $expire = 0 ) {
  * @param string     $group Optional. Where the cache contents are grouped. Default empty.
  * @param bool       $force Optional. Whether to force an update of the local cache
  *                          from the persistent cache. Default false.
- * @param bool       $found Optional. Whether the key was found in the cache (passed by reference).
+ * @param bool|null  $found Optional. Whether the key was found in the cache (passed by reference).
  *                          Disambiguates a return of false, a storable value. Default null.
  * @return mixed|false The cache contents on success, false on failure to retrieve contents.
  */