| // Test that we get implied bounds from complex projections after normalization. |
| |
| //@ check-pass |
| |
| // implementations wil ensure that |
| // WF(<T as Combine<'a>>::Ty) implies T: 'a |
| trait Combine<'a> { |
| type Ty; |
| } |
| |
| impl<'a, T: 'a> Combine<'a> for Box<T> { |
| type Ty = &'a T; |
| } |
| |
| // ======= Wrappers ====== |
| |
| // normalizes to a projection |
| struct WrapA<T>(T); |
| impl<'a, T> Combine<'a> for WrapA<T> |
| where |
| T: Combine<'a>, |
| { |
| type Ty = T::Ty; |
| } |
| |
| // <WrapB<T> as Combine<'a>>::Ty normalizes to a type variable ?X |
| // with constraint `<T as Combine<'a>>::Ty == ?X` |
| struct WrapB<T>(T); |
| impl<'a, X, T> Combine<'a> for WrapB<T> |
| where |
| T: Combine<'a, Ty = X>, |
| { |
| type Ty = X; |
| } |
| |
| // <WrapC<T> as Combine<'a>>::Ty normalizes to `&'a &'?x ()` |
| // with constraint `<T as Combine<'a>>::Ty == &'a &'?x ()` |
| struct WrapC<T>(T); |
| impl<'a, 'x: 'a, T> Combine<'a> for WrapC<T> |
| where |
| T: Combine<'a, Ty = &'a &'x ()>, |
| { |
| type Ty = &'a &'x (); |
| } |
| |
| //==== Test implied bounds ====== |
| |
| fn test_wrap<'a, 'b, 'c1, 'c2, A, B>( |
| _: <WrapA<Box<A>> as Combine<'a>>::Ty, // normalized: &'a A |
| _: <WrapB<Box<B>> as Combine<'b>>::Ty, // normalized: &'b B |
| _: <WrapC<Box<&'c1 ()>> as Combine<'c2>>::Ty, // normalized: &'c2 &'c1 () |
| ) { |
| None::<&'a A>; |
| None::<&'b B>; |
| None::<&'c2 &'c1 ()>; |
| } |
| |
| fn main() {} |