protected function pushClosureNode(\Twig_Node $blocks, \Twig_Node_Expression $variables, $parentName, \Twig_Node_Block $previous = null)
    {
        if (null === $previous) {
            return;
        }

        $name = $previous->getAttribute('name');
        $reference = new SuperblockReference($name, $variables, [], $previous->getTemplateLine(), $previous->getNodeTag());
        $reference->setAttribute('is_closure', true);
        $reference->setAttribute('parent_name', $parentName);

        $this->parser->setBlock($name, $previous);
        $blocks->setNode(\count($blocks), $reference);
    }