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trait Foo {}
trait Trait {
type Associated;
}
trait DerivedTrait: Trait {}
trait GenericTrait<A> {
type Associated;
}
struct Impl;
impl Foo for Impl {}
impl Trait for Impl {
type Associated = ();
}
impl DerivedTrait for Impl {}
impl<A> GenericTrait<A> for Impl {
type Associated = ();
}
fn returns_opaque() -> impl Trait + 'static {
Impl
}
fn returns_opaque_derived() -> impl DerivedTrait + 'static {
Impl
}
fn returns_opaque_foo() -> impl Trait + Foo {
Impl
}
fn returns_opaque_derived_foo() -> impl DerivedTrait + Foo {
Impl
}
fn returns_opaque_generic() -> impl GenericTrait<()> + 'static {
Impl
}
fn returns_opaque_generic_foo() -> impl GenericTrait<()> + Foo {
Impl
}
fn returns_opaque_generic_duplicate() -> impl GenericTrait<()> + GenericTrait<u8> {
Impl
}
fn accepts_trait<T: Trait<Associated = ()>>(_: T) {}
fn accepts_generic_trait<T: GenericTrait<(), Associated = ()>>(_: T) {}
fn check_generics<A, B, C, D, E, F, G>(a: A, b: B, c: C, d: D, e: E, f: F, g: G)
where
A: Trait + 'static,
B: DerivedTrait + 'static,
C: Trait + Foo,
D: DerivedTrait + Foo,
E: GenericTrait<()> + 'static,
F: GenericTrait<()> + Foo,
G: GenericTrait<()> + GenericTrait<u8>,
{
accepts_trait(a);
//~^ ERROR type mismatch resolving `<A as Trait>::Associated == ()`
accepts_trait(b);
//~^ ERROR type mismatch resolving `<B as Trait>::Associated == ()`
accepts_trait(c);
//~^ ERROR type mismatch resolving `<C as Trait>::Associated == ()`
accepts_trait(d);
//~^ ERROR type mismatch resolving `<D as Trait>::Associated == ()`
accepts_generic_trait(e);
//~^ ERROR type mismatch resolving `<E as GenericTrait<()>>::Associated == ()`
accepts_generic_trait(f);
//~^ ERROR type mismatch resolving `<F as GenericTrait<()>>::Associated == ()`
accepts_generic_trait(g);
//~^ ERROR type mismatch resolving `<G as GenericTrait<()>>::Associated == ()`
}
fn main() {
accepts_trait(returns_opaque());
//~^ ERROR type mismatch resolving `<impl Trait as Trait>::Associated == ()`
accepts_trait(returns_opaque_derived());
//~^ ERROR type mismatch resolving `<impl DerivedTrait as Trait>::Associated == ()`
accepts_trait(returns_opaque_foo());
//~^ ERROR type mismatch resolving `<impl Trait + Foo as Trait>::Associated == ()`
accepts_trait(returns_opaque_derived_foo());
//~^ ERROR type mismatch resolving `<impl DerivedTrait + Foo as Trait>::Associated == ()`
accepts_generic_trait(returns_opaque_generic());
//~^ ERROR type mismatch resolving `<impl GenericTrait<()> as GenericTrait<()>>::Associated == ()`
accepts_generic_trait(returns_opaque_generic_foo());
//~^ ERROR type mismatch resolving `<impl GenericTrait<()> + Foo as GenericTrait<()>>::Associated == ()`
accepts_generic_trait(returns_opaque_generic_duplicate());
//~^ ERROR type mismatch resolving `<impl GenericTrait<()> + GenericTrait<u8> as GenericTrait<()>>::Associated == ()`
}
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