// https://github.com/rust-lang/rust/issues/73481 // This test used to cause unsoundness, since one of the two possible // resolutions was chosen at random instead of erroring due to conflicts. #![feature(type_alias_impl_trait)] type X = impl ToString; fn f(a: A, b: B) -> (X, X) { (a.clone(), a) //~^ ERROR concrete type differs from previous defining opaque type } fn main() { println!("{}", as ToString>::to_string(&f(42_i32, String::new()).1)); }