Question

Suppose I have the following code:

trait Trait1 { 
  trait Inner {
    val name = "Inner1"
  }
}

trait Trait2 {
  trait Inner {
    val name = "Inner2"
  }
}

class Foo extends Trait1 with Trait2 {
  // I want Concrete1 to be a Trait1.Inner not a Trait2.Inner
  class Concrete1 extends Inner
  val c = new Concrete1
}

object Obj {
  def main(args: Array[String]): Unit = {
    val foo = new Foo
    println(foo.c.name)
  }
}

When I mix in Trait1 and Trait2, referring to Inner seems to default to the Inner type of whichever trait I mixin second; so when I call Obj‘s main method it prints Inner2. How can I refer to Trait1.Inner in Foo? All three of the following give compiler errors:

class Concrete1 extends Trait1.Inner
class Concrete1 extends Trait1$Inner
class Concrete1 extends Trait1#Inner

Answer 1

Instead of

class Concrete1 extends Inner

Use this

class Concrete1 extends super[Trait1].Inner

That should get you what you want