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//@ revisions: current next
//@ ignore-compare-mode-next-solver (explicit revisions)
//@[next] compile-flags: -Znext-solver
//@[next] check-pass
// Regression test for trait-system-refactor-initiative#106. We previously
// tried to define other opaques while checking that opaques are well-formed.
//
// This resulted in undesirable ambiguity
#![feature(type_alias_impl_trait)]
mod ex0 {
fn foo() -> (impl Sized, impl Sized) {
((), ())
}
}
mod ex1 {
type Tait1 = impl Sized;
//[current]~^ ERROR unconstrained opaque type
fn foo(x: Tait1) -> impl Sized {
let () = x;
}
}
mod ex2 {
type Tait1 = impl Sized;
//[current]~^ ERROR unconstrained opaque type
type Tait2 = impl Sized;
fn foo(x: Tait1) -> Tait2 {
let () = x;
}
}
mod ex3 {
type Tait1 = impl Sized;
//[current]~^ ERROR unconstrained opaque type
trait Something<T> {}
impl<T, U> Something<U> for T {}
type Tait2 = impl Something<Tait1>;
fn foo(x: Tait1) -> Tait2 {
let () = x;
}
}
mod ex4 {
type Tait1 = impl Sized;
//[current]~^ ERROR unconstrained opaque type
trait Trait<U> {
type Assoc;
}
impl<T, U> Trait<U> for T {
type Assoc = T;
}
// ambiguity when checking that `Tait2` is wf
//
// ambiguity proving `(): Trait<Tait1>`.
type Tait2 = impl Trait<(), Assoc = impl Trait<Tait1>>;
fn foo(x: Tait1) -> Tait2 {
let () = x;
}
}
fn main() {}
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