"Unreachable case" warning when pattern matching on an option of opaque type

[avella2409]

Hello, when using an opaque type I've encountered a behavior that I was not expecting.
I would like to understand why in the following example, when using List, I got an Unreachable case warning, but when using Set, everything is fine. I know that List is a class and Set is a trait but have no idea why it says Unreachable case.

object Context {
    opaque type SomeOpaqueType[A] <: A = A
}

import Context.*

def unreachableCaseExample(): Unit = 
    val errorWithList: Option[SomeOpaqueType[List[String]]] = ???

    errorWithList match
        case Some(value) => ??? // 'Unreachable case' error
        case None => ???

    val worksWithSet: Option[SomeOpaqueType[Set[String]]] = ???

    worksWithSet match
        case Some(value) => ??? // Everything is fine
        case None => ???

Do you have any idea? (Scala 3.3.1)

[sjrd]

Looks like a bug to me.

The cause might be related to the fact that List is covariant but Set isn't.