Is this a bug in opaque types?

[mwisnicki]

trait Entity[T <: Entity[?]] {
  def id: Types.Id[T] = Types.defaultId
}
object Types {
  opaque type Id[T <: Entity[?]] = Long
  def defaultId[T <: Entity[?]]: Id[T] = 0L
}
List[Entity[?]]().groupBy(_.id).get("not an opaque long")

The above code compiles but maybe shouldn't?
The key of that map should be of opaque type Id but instead becomes Any.

[sjrd]

What behavior do you get and what did you expect instead?

If you don't know whether it's a bug or not, then there are more chances that its is correct than buggy. Perhaps ask on https://users.scala-lang.org/ instead?

[mwisnicki]

I updated my question with expectation and actual behavior. Will try posting on the other site, thanks.

[mwisnicki]

https://users.scala-lang.org/t/is-this-a-bug-in-opaque-types/10728 for reference