macro_rules! mac { ($attr_item: meta) => { #[cfg($attr_item)] //~^ ERROR expected unsuffixed literal, found `meta` metavariable //~| ERROR expected unsuffixed literal, found `meta` metavariable struct S; } } mac!(an(arbitrary token stream)); #[cfg(feature = -1)] //~^ ERROR expected unsuffixed literal, found `-` //~| ERROR expected unsuffixed literal, found `-` fn handler() {} fn main() {}