"We merged an early C# 15 preview feature into .NET 11 preview 3: unions.

Adds union declarations (`union Pet(Cat, Dog, Bird) { ... }`) and union types (attributed with `[Union]`).
They can be treated by pattern matching/switch expressions as a closed set for exhaustiveness. " -Julien Couvreur

https://github.com/dotnet/csharplang/blob/main/proposals/unions.md

#dotnet #csharp