But since rust is compiled, in practice that would be like C unions, right? A pain to work with I mean typescript has those because the underlying runtime is J

But since rust is compiled, in practice that would be like C unions, right? A pain to work with I mean typescript has those because the underlying runtime is Javascript, which tracks the types of stuff and handles some kind of polymorphism, so you can get away with undiscriminated unions because the runtime is doing the job of discriminating them