[utf_8x]

Hell yeah! After all these years it's finally here.

One thing I miss here (and admittedly I only skimmed through the post so if I missed this, please do correct me) is "ad hoc" unions.

It would be great to be able to do something like

  public Union<TypeA, TypeB> GetThing()...

Without having to declare the union first. Basically OneOf<...> but built-in and more integrated

[debugnik]

I guess you can define

  union Union<T1, T2>(T1, T2);

Add a bunch of overloads and you'd replicate for T1|T2 syntax the equivalent mess to (Value)Tuple<...> that eventually became the backing for actual tuple syntax.