rust/tests/ui/traits/trait-upcasting/illegal-upcast-from-impl.rs
Urgau 4c2d6de70e Stabilize RFC3324 dyn upcasting coercion
Aka trait_upcasting feature.

And also adjust the `deref_into_dyn_supertrait` lint.
2023-11-22 13:56:36 +01:00

22 lines
482 B
Rust

// revisions: current next
//[next] compile-flags: -Ztrait-solver=next
trait Super {
type Assoc;
}
trait Sub: Super {}
impl<T: ?Sized> Super for T {
type Assoc = i32;
}
fn illegal(x: &dyn Sub<Assoc = ()>) -> &dyn Super<Assoc = i32> { x }
//~^ ERROR mismatched types
// Want to make sure that we can't "upcast" to a supertrait that has a different
// associated type that is instead provided by a blanket impl (and doesn't come
// from the object bounds).
fn main() {}