Comment by amitport

I may be wrong, but I don't think this is what people mean by 'sum types'.

I was expecting union types (e.g., https://www.typescriptlang.org/docs/handbook/unions-and-inte... or https://dotty.epfl.ch/docs/reference/new-types/union-types.h... )

I guess enums are a type of sum type, but seems this is more specifically about enums