rust/tests/ui/coherence/occurs-check/opaques.rs

39 lines
793 B
Rust

//@revisions: old next
//@[next] compile-flags: -Znext-solver
// A regression test for #105787
//@[old] known-bug: #105787
//@[old] check-pass
#![feature(type_alias_impl_trait)]
mod defining_scope {
use super::*;
pub type Alias<T> = impl Sized;
pub fn cast<T>(x: Container<Alias<T>, T>) -> Container<T, T> {
//[next]~^ ERROR type annotations needed
x
}
}
struct Container<T: Trait<U>, U> {
x: <T as Trait<U>>::Assoc,
}
trait Trait<T> {
type Assoc;
}
impl<T> Trait<T> for T {
type Assoc = Box<u32>;
}
impl<T> Trait<T> for defining_scope::Alias<T> {
//[next]~^ ERROR conflicting implementations of trait
type Assoc = usize;
}
fn main() {
let x: Box<u32> = defining_scope::cast::<()>(Container { x: 0 }).x;
println!("{}", *x);
}