Default-value annotation

[malcolmredheron]

As I understand it, the intended procedure when adding a field to a case class that I have serialized with upickle is to give it a default value, so that I can continue to read old data

However, if I do this then I lose type safety, since all of my existing code, which doesn't pass the value, still compiles. So I have to define a matching object for the case class, with an apply() method that has all the same arguments and passes them through. It's a bit of a drag

Would you consider an annotation that provides the default value? Or is there some other way to do what I'm trying to do?