mirror of https://github.com/rust-lang/rust
28 lines
973 B
Rust
28 lines
973 B
Rust
// Test for a less than ideal interaction of implied bounds and normalization.
|
|
trait Tr {
|
|
type Ty;
|
|
}
|
|
|
|
impl<T: 'static> Tr for T {
|
|
type Ty = &'static T;
|
|
}
|
|
|
|
// `<&'a u8 as Tr>::Ty` should cause an error because `&'a u8: Tr` doesn't hold for
|
|
// all possible 'a. However, we consider normalized types for implied bounds.
|
|
//
|
|
// We normalize this projection to `&'static &'a u8` and add a nested `&'a u8: 'static`
|
|
// bound. This bound is then proven using the implied bounds for `&'static &'a u8` which
|
|
// we only get by normalizing in the first place.
|
|
fn test<'a>(x: &'a u8, _wf: <&'a u8 as Tr>::Ty) -> &'static u8 { x }
|
|
|
|
fn main() {
|
|
// This works as we have 'static references due to promotion.
|
|
let _: &'static u8 = test(&3, &&3);
|
|
// This causes an error because the projection requires 'a to be 'static.
|
|
// It would be unsound if this compiled.
|
|
let x: u8 = 3;
|
|
let _: &'static u8 = test(&x, &&3);
|
|
//~^ ERROR `x` does not live long enough
|
|
|
|
}
|