gcc/testsuite/rust/compile/issues/2225.rs

#![feature(no_core)]
#![no_core]

macro_rules! foo {
    ($_:tt) => {};
    () => {foo!($);};
}

macro_rules! bar {
    () => {let $_a = 12;} // { dg-error "expecting .;. but .\\$. found" }
}

pub fn main() -> i32 {
    foo!();
    bar!();
    0
}