Long-winded because not able to refer to type in super-class type parameter list.

gistfile1.txt

  class Editor[T](initialValue: T)
  class A[F, E <: Editor[F]](fieldMaker: () => F, edMaker: F => E) {
   val field: F = fieldMaker()
   val editor: E = edMaker(field)
  }
  locally { //Long
  class B(opStringTypeMaker: () => (Option[String]))
   extends A[Option[String], Editor[Option[String]]](opStringTypeMaker, opS => new Editor(opS)) {
  }
   val b = new B(() => Some("First"))
  }
  locally { //Better
   type X = Option[String]
   class B(opStringTypeMaker: () => X)
    extends A[X, Editor[X]](opStringTypeMaker, new Editor(_: X)) {
   }
   val b = new B(() => Some("First"))
  }
  locally { //Ideal
   class B(opStringTypeMaker: () => super.F)
    extends A[Option[String], Editor[super.F]](opStringTypeMaker, new Editor(_: super.F)) {
   }
   val b = new B(() => Some("First"))
  }
 }