error[E0283]: type annotations needed
  --> $DIR/leak-check-in-selection-6-ambig-unify.rs:30:5
   |
LL |     impls_trait::<(), _, _>()
   |     ^^^^^^^^^^^^^^^^^^^^^^^ cannot infer type of the type parameter `U` declared on the function `impls_trait`
   |
note: multiple `impl`s satisfying `(): Trait<_, _>` found
  --> $DIR/leak-check-in-selection-6-ambig-unify.rs:26:1
   |
LL | impl<V> Trait<u32, V> for () where for<'b> (): LeakCheckFailure<'static, 'b, V> {}
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
LL | impl<V> Trait<u16, V> for () {}
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
note: required by a bound in `impls_trait`
  --> $DIR/leak-check-in-selection-6-ambig-unify.rs:28:19
   |
LL | fn impls_trait<T: Trait<U, V>, U: Id<V>, V>() {}
   |                   ^^^^^^^^^^^ required by this bound in `impls_trait`

error: aborting due to 1 previous error

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