Can't summon Mirror for a sealed trait containing another sealed trait

[ghostdogpr]

Compiler version

3.0.0-RC3

Minimized code

import scala.deriving.Mirror
import scala.compiletime._

sealed trait SomeTrait
object SomeTrait {
  case class B(a: Int) extends SomeTrait
  case class C(a: Int) extends SomeTrait
  sealed trait SomeOtherTrait extends SomeTrait
  case class D(a: Int) extends SomeOtherTrait
}

summonInline[Mirror.Of[SomeTrait]]

Output

cannot reduce summonFrom with
 patterns :  case given t @ _:deriving.Mirror.Of[SomeTrait]

Expectation

A mirror is summoned.

I am currently trying to cross-build a library with Scala 3 and rewriting the typeclass derivation logic. I ran into this issue when dealing with nested sealed traits. Is that intended? Is there any workaround?

[odersky]

That's not supported yet. See #11686

[dwijnand]

Duplicate of lampepfl/dotty-feature-requests#161.