error[E0207]: the type parameter `T` is not constrained by the impl trait, self type, or predicates
  --> $DIR/refine-resolution-errors.rs:9:6
   |
LL | impl<T: ?Sized> Mirror for () {
   |      ^ unconstrained type parameter

error[E0282]: type annotations needed
  --> $DIR/refine-resolution-errors.rs:15:5
   |
LL |     async fn first() -> <() as Mirror>::Assoc;
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot infer type

error: aborting due to 2 previous errors

Some errors have detailed explanations: E0207, E0282.
For more information about an error, try `rustc --explain E0207`.