Representing a union case in multiple unions

[callius]

I am spoiled by Kotlin's sealed classes/interfaces which allow for state compositions like:

sealed interface Failure {

    sealed interface Case1 : Failure

    sealed interface Case2 : Failure

    data class NotFoundById(/* properties */) : Case1

    data object Unexpected : Case1, Case2
}

// Imported members from Failure

fun test(case1: Case1, case2: Case2) {
    when (case1) {
        is NotFoundById -> Unit
        Unexpected -> Unit
    }

    when (case2) {
        Unexpected -> Unit
    }
}

Ignoring the parent Failure interface, is there a way to model Case1 and Case2 using Freezed?

I have tried two approaches:

// 1
@freezed
class Case1 with _$Case1 {
  const factory Case1.notFoundById(/* properties */) = _NotFoundById1;
  const factory Case2.unexpected() = _Unexpected1;
}

@freezed
class Case2 with _$Case2 {
  const factory Case2.unexpected() = _Unexpected2;
}

// 2
@freezed
class Case1 with _$Case1 {
  const factory Case1.notFoundById(NotFoundById parent) = _NotFoundById1;
  const factory Case2.unexpected(Unexpected parent) = _Unexpected1;
}

@freezed
class Case2 with _$Case2 {
  const factory Case2.unexpected(Unexpected parent) = _Unexpected2;
}

@freezed
class NotFoundById with _$NotFoundById {
  const factory NotFoundById(/* properties */) = _NotFoundById;
}

@freezed
class Unexpected with _$Unexpected {
  const factory Unexpected() = _Unexpected;
}

1 defines duplicate cases and does not support inheritance.
2, while more accurate, is more verbose and also does not support inheritance.

Is there a better way to model this use case?

[rrousselGit]

It's going to be difficult. Pattern matching without built-in language support is going to be very limited in general.

Your solutions are alright. Maybe there's a better one, but I'm not sure