Code for those who can’t see images:

@Serializable
data class SerializableSomething(
  val i: SomeInterface,
  val b: SomeClass, <- error here
)

interface SomeInterface

class SomeClass

Background: we just had a crash where a sealed interface was not marked as Serializable and relied upon that kotlinx usually fails the compilation if a type is not serializable

I really want to disable that behavior