public function allowsNull()
    {
        if (!empty($this->node->type)) {
            // with type hint, checks if NULL constant provided
            if ($this->node->default instanceof Node\Expr\ConstFetch
                && $this->node->default->name instanceof Node\Name
                && strcasecmp('null', (string)$this->node->default->name) === 0
            ) {
                return true;
            }
            return false;
        }
        return true;
    }