{"ast_node_type":"variable","tokens":[{"end":51,"kind":"keyword","start":0,"text":"let"}]}
        let invoc_id = id.placeholder_to_expn_id();
    fn visit_invoc(&mut self, id: NodeId) -> LocalExpnId {
        let old_parent_scope = self.r.invocation_parent_scopes.insert(invoc_id, self.parent_scope);