--TEST-- Testing trait_exists() --FILE-- <?php trait foo { } var_dump(trait_exists('foo')); var_dump(trait_exists(1)); var_dump(trait_exists(NULL)); var_dump(trait_exists(new stdClass)); ?> --EXPECTF-- bool(true) bool(false) bool(false) Warning: trait_exists() expects parameter 1 to be string, object given in %s on line %d NULL