1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
|
// test for #110696
// failed to resolve instance for <Scope<()> as MyIndex<()>>::my_index
// ignore-tidy-linelength
#![feature(type_alias_impl_trait)]
use std::marker::PhantomData;
trait MyIndex<T> {
type O;
fn my_index(self) -> Self::O;
}
trait MyFrom<T>: Sized {
type Error;
fn my_from(value: T) -> Result<Self, Self::Error>;
}
trait F {}
impl F for () {}
type DummyT<T> = impl F;
#[define_opaque(DummyT)]
fn _dummy_t<T>() -> DummyT<T> {}
struct Phantom1<T>(PhantomData<T>);
struct Phantom2<T>(PhantomData<T>);
struct Scope<T>(Phantom2<DummyT<T>>);
impl<T> Scope<T> {
#[define_opaque(DummyT)]
fn new() -> Self {
//~^ ERROR item does not constrain
unimplemented!()
}
}
impl<T> MyFrom<Phantom2<T>> for Phantom1<T> {
type Error = ();
fn my_from(_: Phantom2<T>) -> Result<Self, Self::Error> {
unimplemented!()
}
}
impl<T: MyFrom<Phantom2<DummyT<U>>>, U> MyIndex<DummyT<T>> for Scope<U> {
//~^ ERROR the type parameter `T` is not constrained by the impl
type O = T;
#[define_opaque(DummyT)]
fn my_index(self) -> Self::O {
MyFrom::my_from(self.0).ok().unwrap()
}
}
fn main() {
let _pos: Phantom1<DummyT<()>> = Scope::new().my_index();
}
|
