If I have a function `fun <T, R> Optional&lt...

# announcements

[Eric O'Connell]

If I have a function fun <T, R> Optional<T>.mapDefault(default: R, mapper: (T) -> R): R and call it with a default of a subtype of a sealed class e.g. maybeThing.mapDefault(Action.NoFoo) { thing -> Action.Foo } then this fails type checking because R in mapDefault is bound to Action.NoFoo — is there a good way around this besides calling maybeThing.mapDefault<Thing, Action> ?

[streetsofboston]

Introduce a generic super type.

[streetsofboston]

e.g.
fun <T, S, D : S, R : S> Optional<T>.mapDefault(default: D, mapper: (T) -> R): S

[Eric O'Connell]

wow, niiiice

[Eric O'Connell]

Thank you!