{"ast_node_type":"variable","tokens":[{"end":100,"kind":"keyword","start":0,"text":"let"}]}
                    let tok_result = match expander.expand(self.cx, span, mac.args.tokens.clone()) {
                SyntaxExtensionKind::LegacyBang(expander) => {
                        ExpandResult::Ready(tok_result) => tok_result,