That's the point I tried to make. All my bachelor education there was no single mention of sum types even though we learned about the visitor pattern. Instead of having to model sum types with object hierarchies, the language should provide a straightforward way to represent them since it's a very basic concept. I think that while things have improved a lot compared to past, sum types concept is still not known as much as objects for instance. Today all mainstream languages added direct support for sum types but awareness of it lacks.