I have a sealed class (closed polymorphism) that i...

# serialization

[rocketraman]

I have a sealed class (closed polymorphism) that implements an interface (open).

Is there a way to define the SerializersModule to define the subclasses for the open polymorphic interface via delegation to the sealed class, rather than listing all of the sealed classes subclasses explicitly (which the compiler will not check is exhaustive)? More in 🧵 .

[rocketraman]

I've tried:

polymorphic(MyOpenInterface::class) {
  subclass(MySealed::class)
}

but that fails with:

Serializer for MySealed can't be registered as a subclass for polymorphic serialization because its kind SEALED is not concrete. To work with multiple hierarchies, register it as a base class.

but I'm not sure how to do that.

[rocketraman]

Created https://github.com/Kotlin/kotlinx.serialization/issues/2782