error[E0283]: type annotations needed: cannot satisfy `impl Trait<'_> + Trait<'_>: Trait<'_>`
  --> $DIR/ambiguity-due-to-uniquification-2.rs:16:5
   |
LL |     impls_trait::<'y, _>(foo::<'x, 'y>());
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: cannot satisfy `impl Trait<'_> + Trait<'_>: Trait<'_>`
   = help: the trait `Trait<'t>` is implemented for `()`
note: required by a bound in `impls_trait`
  --> $DIR/ambiguity-due-to-uniquification-2.rs:13:23
   |
LL | fn impls_trait<'x, T: Trait<'x>>(_: T) {}
   |                       ^^^^^^^^^ required by this bound in `impls_trait`

error: aborting due to 1 previous error

For more information about this error, try `rustc --explain E0283`.