Implicit conversion with abstract HKT not firing

[japgolly]

Compiler version

3.0.0-RC3

Minimized code

sealed abstract class CtorType[P]

object CtorType {
  final class Props[P] extends CtorType[P] {
    def whyHelloThere(props: P): Unit = ()
  }
}

trait Comp[P, CT[p] <: CtorType[p]] {
  val ctor: CT[P]
}
object Comp {
  implicit def autoCtor[P, CT[p] <: CtorType[p]](c: Comp[P, CT]): CT[P] = c.ctor
}

object Test {
  val comp: Comp[Int, CtorType.Props] = ???

  comp.whyHelloThere(3)                // error: should work
  Comp.autoCtor(comp).whyHelloThere(3) // works
}

Output

[error] 20 |  comp.whyHelloThere(3)                // error: should work
[error]    |  ^^^^^^^^^^^^^^^^^^
[error]    |  value whyHelloThere is not a member of Comp[Int, CtorType.Props]
[error] one error found

Expectation

It works in Scala 2.x, it should work here too.

Workaround

Duplicate the autoCtor for each subclass of CtorType, remove the CT type param, and hardcode the CT value.

  // implicit def autoCtor[P, CT[p] <: CtorType[p]](c: Comp[P, CT]): CT[P] = c.ctor
  implicit def autoCtorP[P](c: Comp[P, CtorType.Props]): CtorType.Props[P] = c.ctor