//@ run-pass struct CustomEq; impl Eq for CustomEq {} impl PartialEq for CustomEq { fn eq(&self, _: &Self) -> bool { false } } #[derive(PartialEq, Eq)] #[allow(unused)] enum Foo { Bar, Baz, Qux(CustomEq), } const BAR_BAZ: Foo = if 42 == 42 { Foo::Bar } else { Foo::Qux(CustomEq) // dead arm }; fn main() { match Foo::Qux(CustomEq) { BAR_BAZ => panic!(), _ => {} } }