How could an idiomatic design of Serializable/Cloneable/… look like in Scala?

Question

I wonder how much different these funcionality would look like (and how different the implementation would be), if Scala wouldn\'t (have to) follow Java\'s java.io.Seriali

Answer 1

Or are marker interfaces still the right choice in Scala?

Nope. They aren't even the right choice in Java. They should be annotations, not interfaces.