If a sealed class is marked as

Immutable

are all of its subclasses considered

Immutable

as well?

I think not. Sealed or not, the fact a super class is

Immutable

tells you nothing about the contract for the subclasses.

@jim is this still the case? In https://kotlinlang.slack.com/archives/CJLTWPH7S/p1637743593403000?thread_ts=1637743593.403000&cid=CJLTWPH7S @Csaba Kozák pointed out that the compiler seems to be marking classes as stable if they have a supertype that is stable.