error[E0220]: associated type `Assoc` not found for `Trait`
  --> $DIR/stranded-opaque.rs:8:31
   |
LL | fn produce<T>() -> impl Trait<Assoc = impl Trait> {
   |                               ^^^^^ associated type `Assoc` not found

error: aborting due to 1 previous error

For more information about this error, try `rustc --explain E0220`.