error: expected identifier, found keyword `async` --> $DIR/edition-keywords-2018-2018-expansion.rs:8:5 | LL | produces_async! {} | ^^^^^^^^^^^^^^^^^^ expected identifier, found keyword | = note: this error originates in the macro `produces_async` (in Nightly builds, run with -Z macro-backtrace for more info) help: escape `async` to use it as an identifier | LL | () => (pub fn r#async() {}) | ++ error: aborting due to previous error