error[E0308]: mismatched types
  --> $DIR/multiple-def-uses-in-one-fn3.rs:14:9
   |
LL | type X<A: ToString + Clone, B: ToString + Clone> = impl ToString;
   |                                                    ------------- the expected opaque type
...
LL | fn g<A: ToString + Clone, B: ToString + Clone>(a: A, b: B) -> (X<A, B>, X<A, B>) {
   |      -                    - found type parameter
   |      |
   |      expected type parameter
LL |     (a, b)
   |         ^ expected type parameter `A`, found type parameter `B`
   |
   = note: expected opaque type `X<A, B>`
           found type parameter `B`
   = note: a type parameter was expected, but a different one was found; you might be missing a type parameter or trait bound
   = note: for more information, visit https://doc.rust-lang.org/book/ch10-02-traits.html#traits-as-parameters

error: aborting due to previous error

For more information about this error, try `rustc --explain E0308`.