3 // revisions: migrate mir
4 //[mir]compile-flags: -Z borrowck=mir
6 #![feature(member_constraints)]
8 trait Trait<'a, 'b> { }
9 impl<T> Trait<'_, '_> for T { }
11 // Here we wind up selecting `'a` and `'b` in the hidden type because
12 // those are the types that appear in the original values.
14 fn upper_bounds<'a, 'b>(a: &'a u8, b: &'b u8) -> impl Trait<'a, 'b> {
15 // In this simple case, you have a hidden type `(&'0 u8, &'1 u8)` and constraints like
24 // We use the fact that `'a: 0'` must hold (combined with the in
25 // constraint) to determine that `'0 = 'a` must be the answer.