diff --git a/core/includes/form.inc b/core/includes/form.inc
index 537eff8..1c88201 100644
--- a/core/includes/form.inc
+++ b/core/includes/form.inc
@@ -78,7 +78,7 @@ function template_preprocess_select(&$variables) {
  *   $element['#options'] above, or NULL. This parameter is only used internally
  *   and is not intended to be passed in to the initial function call.
  *
- * @return array
+ * @return mixed[]
  *   A structured, possibly nested, array of options and optgroups for use in a
  *   select form element.
  *   - label: A translated string whose value is the text of a single HTML