[MadsTorgersen]

There's a great proposal for adding type classes to C# here: https://github.com/MattWindsor91/roslyn/blob/master/concepts...

And I discuss some ways that could be integrated with the extension everything proposal here: https://github.com/dotnet/csharplang/issues/164

The problem with both is that there's a new notion of "shape" or "concept" that's different from interfaces. It would be nice to just use interfaces for this (which is what I hint at in the video), but that comes with its own downsides and limitations.