space: Fix how sealed abstract classes decompose

[dwijnand]

No description provided.

[dwijnand]

Me: "Hmm, GitHub won't suggest a reviewer, let me find the author so I can request them." "Ah, I'm the author, that's why." #14599 😄

[anatoliykmetyuk]

sealed trait Baz, val x = new Baz {}, Baz.children returns Baz

Which exactly Baz in Baz.children are we talking about here?

[dwijnand]

Sounds like a joke question 😄 . Describing a full, legal, source file:

sealed trait Baz
object Baz:
  val inst = new Baz {}

Then there are 3 classes: Baz, the interface, Baz$, the module class, and Baz$$anon$1, the anonymous subclass of Baz:

$ javap Baz.class
Compiled from "Test.scala"
public interface Baz {
  public static Baz inst();
}
$ javap Baz\$.class
Compiled from "Test.scala"
public final class Baz$ implements java.io.Serializable {
  public static final Baz$ MODULE$;
  public static {};
  public Baz inst();
}
$ javap Baz\$\$anon\$1.class
Compiled from "Test.scala"
public final class Baz$$anon$1 implements Baz {
  public Baz$$anon$1();
}

So when you look up the sealed children of Baz, then Baz itself is returned, as a representative of the anonymous subclass.