Hey there. C# language designer here. Working on that here: https://github.com/dotnet/csharplang/tree/main/proposals/dis...
You can start reading through it starting at: https://github.com/dotnet/csharplang/blob/main/proposals/dis...
Definitely want to move to get this in asap :)
Merci Cyrus Jan
Makes me confident in C# to see the language in the hands of talented and clearly passionate designers like you.
As for your DU proposal, between Union types and enums, I think you know that anyone who has used TS or Rust or F# or OCaml will have a strong preference for the Union based syntax.
Good luck with the effort to get it added!