* @param int $revId Revision ID (for {{REVISIONID}})
* @param ParserOptions $options Parser options
* @param bool $generateHtml Whether or not to generate HTML
- * @param ParserOutput $output The output object to fill (reference).
+ * @param ParserOutput &$output The output object to fill (reference).
*/
protected function fillParserOutput( Title $title, $revId,
ParserOptions $options, $generateHtml, ParserOutput &$output