error: concrete type differs from previous defining opaque type use
  --> $DIR/generic_duplicate_param_use2.rs:14:1
   |
LL | / fn two<T: Debug, U>(t: T, _: U) -> Two<T, U> {
LL | |
LL | |     t
LL | | }
   | |_^ expected `U`, got `T`
   |
note: previous use here
  --> $DIR/generic_duplicate_param_use2.rs:10:1
   |
LL | / fn one<T: Debug>(t: T) -> Two<T, T> {
LL | |     t
LL | | }
   | |_^

error: aborting due to previous error