bbPress.org

untested, but this should do it

add_filter ('bbp_after_has_search_results_parse_args', 'my_function')

my_function ($args) {
	
		// bbp_get_closed_status_id() REMOVED,
		$post_statuses = array(
			bbp_get_public_status_id(),
			bbp_get_spam_status_id(),
			bbp_get_trash_status_id()
		);

		// Add support for private status
		if ( current_user_can( 'read_private_topics' ) ) {
			$post_statuses[] = bbp_get_private_status_id();
		}

		// Join post statuses together
		$args['post_status'] = implode( ',', $post_statuses );
		
return $args ;

}