{"ast_node_type":"variable","tokens":[{"end":36,"kind":"keyword","start":0,"text":"let"}]}
        let idx = Self::to_idx(idx);
    pub fn entry(&mut self, idx: Idx<T>) -> Entry<'_, Idx<T>, V> {
        self.v.resize_with((idx + 1).max(self.v.len()), || None);