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[E0277]: the size for values of type `T` cannot be known at compilation time
  --> $DIR/refine-resolution-errors.rs:11:18
   |
LL | impl<T: ?Sized> Mirror for () {
   |      - this type parameter needs to be `Sized`
LL |
LL |     type Assoc = T;
   |                  ^ doesn't have a size known at compile-time
   |
note: required by a bound in `Mirror::Assoc`
  --> $DIR/refine-resolution-errors.rs:7:5
   |
LL |     type Assoc;
   |     ^^^^^^^^^^^ required by this bound in `Mirror::Assoc`
help: consider removing the `?Sized` bound to make the type parameter `Sized`
   |
LL - impl<T: ?Sized> Mirror for () {
LL + impl<T> Mirror for () {
   |
help: consider relaxing the implicit `Sized` restriction
   |
LL |     type Assoc: ?Sized;
   |               ++++++++

error: aborting due to 2 previous errors

Some errors have detailed explanations: E0207, E0277.
For more information about an error, try `rustc --explain E0207`.