error: defining existential type use restricts existential type by using the generic parameter `T` twice
  --> $DIR/generic_duplicate_param_use4.rs:10:1
   |
LL | / fn one<T: Debug>(t: T) -> Two<T, T> {
LL | |
LL | |     t
LL | | }
   | |_^

error: aborting due to previous error