// Regression test for #29859, supertrait version. This example // allowed arbitrary trait bounds to be synthesized. trait Magic: Copy {} impl Magic for T {} fn copy(x: T) -> (T, T) { (x, x) } #[derive(Debug)] struct NoClone; fn main() { let (a, b) = copy(NoClone); //~ ERROR E0275 println!("{:?} {:?}", a, b); }