>compiler can't prove the above code is exhaustive because no proper sum types Thats because c#s enum is not "closed" https://github.com/dotnet/csharplang/iss

>compiler can't prove the above code is exhaustive because no proper sum types Thats because c#s enum is not "closed" https://github.com/dotnet/csharplang/issues/3179 https://github.com/dotnet/csharplang/issues/3179