error[E0283]: type annotations needed
  --> $DIR/where-allowed-2.rs:4:30
   |
LL | fn in_adt_in_return() -> Vec<impl Debug> { panic!() }
   |                              ^^^^^^^^^^ cannot infer type
   |
   = note: the type must implement `Debug`

error: aborting due to 1 previous error

For more information about this error, try `rustc --explain E0283`.
