Extending an inner class

Question
1

I’m facing a design of this form:

   trait A[T]:
      def f: B
      trait B:
         def g(x: T): Seq[T] = Seq.fill(m)(x)
         def n: Int
         def m: Int

   abstract class AB:
      def n: Int
      def m: Int = n + 1

   object O extends A[String]:
      def f: B =
         new AB with B:
            def n: Int = 1

Note how AB defines its own abstract method n and is then mixed in with B. Instead, I’d like AB to extend trait B and simply use n. This doesn’t work:

   abstract class AB extends A[?]#B

Is there a way?

2

It seems to work as a self type:

abstract class AB:
  this: A[?]#B =>
  //def n: Int
  def m: Int = n + 1
3 Likes
3

Ah, good idea. Forgot about self-types…