I have a piece of code that looks like this: ``` fun pairTest(foo: Boolean, bar: Boolean) = ...

# announcements

[pavel]

I have a piece of code that looks like this:

fun pairTest(foo: Boolean, bar: Boolean) =
        when (foo to bar) {
            (true to true) -> 1
            (true to false) -> 2
            (false to true) -> 3
            (false to false) -> 4
        }

IntelliJ is saying that I need an else branch here. How come? And is there a better way to do this?

[pavel]

In my world, a pair of booleans can only have 4 different possible values

[streetsofboston]

The compiler is just not that smart….. An exhaustive when class only works with enums and sealed classes. And even then, you can not get complex in your when conditions.

[raulraja]

Boolean is not implemented in Kotlin as a sealed union and the compiler doesn't know that your match covers all cases in the Pair.

[Andy Gibel]

Might look better with an enum class (Boolean, Boolean) anyway?

[pavel]

makes sense. Thanks

[pavel]

enum class does feel like a good idea…