error[E0038]: the trait `Bar` cannot be made into an object
  --> $DIR/issue-28576.rs:7:12
   |
LL | /            dyn Bar
LL | |               <Assoc=()>
   | |________________________^ the trait `Bar` cannot be made into an object
   |
   = note: the trait cannot use `Self` as a type parameter in the supertraits or where-clauses

error: aborting due to previous error

For more information about this error, try `rustc --explain E0038`.