//@ run-pass //@ pretty-expanded FIXME #23616 struct Element; macro_rules! foo { ($tag: expr, $string: expr) => { if $tag == $string { let element: Box<_> = Box::new(Element); unsafe { return std::mem::transmute::<_, usize>(element); } } } } fn bar() -> usize { foo!("a", "b"); 0 } fn main() { bar(); }