{"ast_node_type":"other","tokens":[{"end":82,"kind":"keyword","start":0,"text":")"}]}
    ) -> Result<ExpandResult<Option<(Mark, Option<Parse<T>>)>>, UnresolvedMacro> {
        eager_callback: EagerCallBackFn<'_>,
        // FIXME: within_limit should support this, instead of us having to extract the error