{"ast_node_type":"variable","tokens":[{"end":78,"kind":"keyword","start":0,"text":"let"}]}
        let ast_id = AstIdWithPath::new(self.file_id(), ast_id, path.clone());
        let &MacroCall { ref path, expand_to, ctxt } = &self.item_tree[ast_id];
        let db = self.def_collector.db;