Comment by dathinab

> reduces the amount of dead boilerplate code other languages struggle with.

given that most of the thinks added seem more inspired by other languages then "moved over" from F# the "other languages struggle with" part makes not that much sense

like some languages which had been ahead of C# and made union type a "expected general purpose" feature of "some kind":

- Java: sealed interfaces (on high level the same this C# features, details differ)

- Rust: it's enum type (but better at reducing boilerplate due to not needing to define a separate type per variant, but being able to do so if you need to)

- TypeScript: untagged sum types + literal types => tagged sum types

- C++: std::variant (let's ignore raw union usage, that is more a landmine then a feature)

either way, grate to have it, it's really convenient to represent a `TYPE is either of TYPES` relationship. Which are conceptually very common and working around them without proper type system support is annoying (but very viable).

I also would say that while it is often associated with functional programing it has become generally expected even if you language isn't functional. Comparable to e.g. having some limited closure support.