diff --git a/lib/outputrenderers.php b/lib/outputrenderers.php
index 115614a67ba19..4f03e45a6ae9e 100644
--- a/lib/outputrenderers.php
+++ b/lib/outputrenderers.php
@@ -170,7 +170,7 @@ public function pix_url($imagename, $component = 'moodle') {
      * @param html_component $component
      * @return void;
      */
-    protected function prepare_event_handlers(&$component) {
+    protected function prepare_event_handlers(html_component $component) {
         $actions = $component->get_actions();
         if (!empty($actions) && is_array($actions) && $actions[0] instanceof component_action) {
             foreach ($actions as $action) {