{"ast_node_type":"variable","tokens":[{"end":38,"kind":"keyword","start":0,"text":"let"}]}
        let start = self.next_node_id;
    fn next_node_ids(&mut self, count: usize) -> std::ops::Range<NodeId> {
        let end = start.as_usize().checked_add(count).expect("input too large; ran out of NodeIds");