| #![feature(type_alias_impl_trait)] | |
| #[derive(Clone)] | |
| struct CopyIfEq<T, U>(T, U); | |
| impl<T: Copy> Copy for CopyIfEq<T, T> {} | |
| type E<'a, 'b> = impl Sized; | |
| #[define_opaque(E)] | |
| fn foo<'a, 'b, 'c>(x: &'static i32, mut y: &'a i32) -> E<'b, 'c> { | |
| let v = CopyIfEq::<*mut _, *mut _>(&mut { x }, &mut y); | |
| // This assignment requires that `x` and `y` have the same type due to the | |
| // `Copy` impl. The reason why we are using a copy to create a constraint | |
| // is that only borrow checking (not regionck in type checking) enforces | |
| // this bound. | |
| let u = v; | |
| let _: *mut &'a i32 = u.1; | |
| unsafe { | |
| let _: &'b i32 = *u.0; | |
| //~^ ERROR lifetime may not live long enough | |
| } | |
| u.0 | |
| } | |
| fn main() {} |