34 lines
857 B
Rust
34 lines
857 B
Rust
|
// Nested impl-traits can impose different member constraints on the same region variable.
|
||
|
|
|
||
|
|
// check-fail
|
||
|
|
|
||
|
|
trait Cap<'a> {}
|
||
|
|
impl<T> Cap<'_> for T {}
|
||
|
|
|
||
|
|
// Assuming the hidden type is `[&'_#15r u8; 1]`, we have two distinct member constraints:
|
||
|
|
// - '_#15r member ['static, 'a, 'b] // from outer impl-trait
|
||
|
|
// - '_#15r member ['static, 'a, 'b] // from inner impl-trait
|
||
|
|
// To satisfy both we can choose 'a or 'b, so it's a failure due to ambiguity.
|
||
|
|
fn fail_early_bound<'s, 'a, 'b>(a: &'s u8) -> impl IntoIterator<Item = impl Cap<'a> + Cap<'b>>
|
||
|
|
where
|
||
|
|
's: 'a,
|
||
|
|
's: 'b,
|
||
|
|
{
|
||
|
|
[a]
|
||
|
|
//~^ E0700
|
||
|
|
//~| E0700
|
||
|
|
}
|
||
|
|
|
||
|
|
// Same as the above but with late-bound regions.
|
||
|
|
fn fail_late_bound<'s, 'a, 'b>(
|
||
|
|
a: &'s u8,
|
||
|
|
_: &'a &'s u8,
|
||
|
|
_: &'b &'s u8,
|
||
|
|
) -> impl IntoIterator<Item = impl Cap<'a> + Cap<'b>> {
|
||
|
|
[a]
|
||
|
|
//~^ E0700
|
||
|
|
//~| E0700
|
||
|
|
}
|
||
|
|
|
||
|
|
fn main() {}
|