#![feature(rustc_attrs)] #[rustc_dummy = stringify!(a)] // OK macro_rules! bar { () => {}; } // FIXME?: `bar` here expands before `stringify` has a chance to expand. // `#[rustc_dummy = ...]` is validated and dropped during expansion of `bar`, // the "unexpected expression" errors comes from the validation. #[rustc_dummy = stringify!(b)] //~ ERROR unexpected expression: `stringify!(b)` bar!(); fn main() {}