error: item constrains opaque type that is not in its signature
  --> $DIR/higher_kinded_params3.rs:26:13
   |
LL |         f = g;
   |             ^
   |
   = note: this item must mention the opaque type in its signature in order to be able to register hidden types
note: this item must mention the opaque type in its signature in order to be able to register hidden types
  --> $DIR/higher_kinded_params3.rs:25:8
   |
LL |     fn successors(&self, mut f: for<'x> fn(&'x ()) -> <&'x A as B>::C) -> Successors<'_> {
   |        ^^^^^^^^^^

error[E0308]: mismatched types
  --> $DIR/higher_kinded_params3.rs:26:9
   |
LL | type Tait<'a> = impl std::fmt::Debug + 'a;
   |                 ------------------------- the expected opaque type
...
LL |         f = g;
   |         ^^^^^ one type is more general than the other
   |
   = note: expected fn pointer `for<'x> fn(&'x ()) -> Tait<'x>`
              found fn pointer `for<'a> fn(&'a ()) -> &'a ()`

error: aborting due to 2 previous errors

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