I’m not sure I agree that Void is a bottom type. If so, void-functions would never be able to return/terminate. Java’s void is probably more of a unit type.
They allude to this later, acknowledging that it’s sort of a cross between unit and bottom.
No it’s not, it is 100% a unit type (except it’s not really a type, since you can only use it as return type and nowhere else)
It’s not possible to instantiate or assign, which is more like a never type than a unit; and it is not possible to define new types with the same properties, which is also more like bottom than unit. But you’re right that it’s not actually a true never type since it can’t represent function divergence.
I think the truth is just that Java’s type system isn’t very mathematically disciplined.
It’s nice that Java has gotten those features but the article is pretty confused about type theory.
It’ll probably take Valhalla for me, personally.
When did you start liking it?
