[klysm]

If I ever implement a product from scratch again, discriminated unions with compiler enforced exhaustive pattern matching is a hard requirement. It’s too powerful to not have.

[nmfisher]

Union types are my biggest wish for Dart, but unfortunately it doesn't look like they'll be added any time soon.

They've recently added support for compiler-enforced pattern matching over sealed classes, which I suppose does get you halfway there though.

[actionfromafar]

What languages could fit that description today? I don't really understand what it even means but maybe I could understand better if I could look at examples in languages which have them.

[phi-go]

For example Rust: https://doc.rust-lang.org/std/keyword.enum.html

[jghn]

Also Scala

[seivan]

Swift, Typescript depending on your opinion with structural typing, and Rust.

Think Scala, Elm and Haskell have it as well.

Having that and elixirs pattern matching would be insane.