Symfony\Bridge\Twig\Extension\FormExtension::__unset PHP Method

    public function __unset($name)
    {
        if ('renderer' === $name) {
            @trigger_error(sprintf('Using the "%s::$renderer" property is deprecated since version 3.2 as it will be removed in 4.0.', __CLASS__), E_USER_DEPRECATED);
        }
        unset($this->{$name});
    }