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kotlinlang

Hi everyone,
Is there a way to have a variable or class have either the type A or B? I have seen something in Arrow Either<A, B> and I wonder if there's something in the language itself too.
If that's not possible I have two enum classes that I want to merge the values at some places so either value can be possible.

There are no union types, yet :disappointed:. This is the ticket to follow: <https://youtrack.jetbrains.com/issue/KT-13108>
For your enums, you could use a (possibly sealed) interface:
```sealed interface AorB
enum class A: AorB { a, b, c }
enum class B: AorB { x, y, z }```

Wow this was so easy and embarrassing to ask :smile:

Having enums implement interfaces is a neat feature that's very easy to overlook! I learned about it back in Java, but I didn't know it was possible until I saw it done in another codebase. So don't be embarassed!

The problem I see now is that the sealed interface must be in the same package as where we implement it.

```package core.definitions.boson

import core.definitions.ParticleType
import core.definitions.attrs.ColorCharge
import core.definitions.attrs.ElectricCharge
import core.definitions.attrs.Spin
import core.utils.idGen

interface Boson : ParticleType {
    val type: BosonType
    val mass: Double
    val electricCharge: ElectricCharge
    val colorCharge: ColorCharge
    val spin: Spin
        get() = Spin.One
    val id: Long
        get() = idGen.incrementAndGet()
}```
And The sealed interface is in
```package core.definitions

sealed interface ParticleType```
I'm getting an error from intelliJ to move Boson into the defnitions package directory.

Yeah, that's true. You can drop the `sealed` keyword and just use a normal interface, but then you'll lose the ability to have an exhaustive `when` over both enums.