A modern programming language that makes developers happier.

kotlinlang

Did you know it's possible to create non-exhaustive enums?

<https://ivan.canet.dev/blog/2026/06/29/kotlin-non-exhaustive-enum.html|Well, it is!>

Fwiw, there's the <https://github.com/livefront/sealed-enum|sealed enum> ksp plugin that can generate entries and such for you.
Using a sealed hierarchy as an enum means, then, that you can add some `internal class NonExhaustive(val nothing: Nothing): MyEnum`, so within your library, you can still get exhaustivity, but outside, users will be forced to use `else`. Even better, this prevents you from accidentally assuming exhaustivity in public inline methods because `NonExhaustive` is not `@PublishedApi`

Another devious trick: you can `RequiresOptIn` with a non-public type... Users thus can't opt-in, unless they do it using the compiler argument

&gt; Another devious trick: you can `RequiresOptIn` with a non-public type... Users thus can't opt-in, unless they do it using the compiler argument
The result is the same as with `DeprecationLevel.Error`

Of course, but (I believe) they can't suppress it then, although you lose `ReplaceWith`. It also means that you don't need to use error suppression