How to set the same type in Scala generators without entering a parameter of the third type?

Question

Currently my trait has an additional type T, which has no real use, except to ensure that B and R have the same common type.

trait GenericBuilder[T <: Any, B <: Builder[T], R <: Result[T]]

To simplify the declaration, I wonder if there is a way to eliminate T in this case, while preserving type rigor.

EDIT: I do not control the Builder or Result code - they are pulled from some Java artifacts outside.

Answer 1

If you just want to simplify this part of the declaration, you can move the types to members, but then you have to go around the cart more because you need a witness that the types are the same:

 trait Builder { type T } trait Result { type T } trait GenericBuilder[B <: Builder, R <: Result] { val w: BT =:= RT }