spurious "cyclic aliasing" error (2)

[sir-wabbit]

abstract class CharSet[P] {
  type Type <: P
}

object LetterOrDigit extends CharSet[Char]
object Digit extends CharSet[LetterOrDigit.Type]

type D = Digit.Type // error: cyclic aliasing or subtyping involving type Type

Possibly related to #8252

---

Without parent trait:

object LetterOrDigit {
  type Type <: Char
}
object Digit {
  type Type <: LetterOrDigit.Type
}
type D = Digit.Type // works fine

Another workaround:

trait CharSet[P] {
  type Type <: P
}
object LetterOrDigit extends { type Type <: Char } with CharSet[Char]
object Digit extends { type Type <: LetterOrDigit.Type } with CharSet[LetterOrDigit.Type]
type D = Digit.Type // works fine