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// edition:2018
trait Trait<'a, 'b> {}
impl<T> Trait<'_, '_> for T {}
// `Ordinary<'a> <: Ordinary<'b>` if `'a: 'b`, as with most types.
//
// I am purposefully avoiding the terms co- and contra-variant because
// their application to regions depends on how you interpreted Rust
// regions. -nikomatsakis
struct Ordinary<'a>(&'a u8);
// Here we get an error because none of our choices (either `'d` nor `'e`) are outlived
// by both `'a` and `'b`.
fn upper_bounds<'a, 'b, 'c, 'd, 'e>(a: Ordinary<'a>, b: Ordinary<'b>) -> impl Trait<'d, 'e>
where
'a: 'e,
'b: 'd,
{
// Hidden type `Ordinary<'0>` with constraints:
//
// ```
// 'a: '0
// 'b: '0
// 'a in ['d, 'e]
// ```
if condition() { a } else { b }
//~^ ERROR hidden type for `impl Trait<'d, 'e>` captures lifetime that does not appear in bounds
}
fn condition() -> bool {
true
}
fn main() {}
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