{"ast_node_type":"other","tokens":[{"end":95,"kind":"keyword","start":0,"text":"//"}]}
                // `Span::at_least_rust_2018()` is somewhat expensive; don't get it repeatedly.
            } else if this.token_uninterpolated_span().at_least_rust_2018() {
                let at_async = this.check_keyword(exp!(Async));