fn main() {
    foo!("hello"); // no import necessary at the root
    bar::baz();
}

mod bar {
    use crate::foo; // this import is required
    pub fn baz() {
        foo!("goodbye");
    }
}

mod test {
    #[macro_export]
    macro_rules! foo {
        ($fmt:expr) => (print!(concat!($fmt, "\n")));
    }
}