Kind Polymorphism

There’s a page of documentation on Kind Polymorphism and a short discussion that was closed earlier this year.

Now that we’re getting close to 3.0 final, I think the doc could benefit from an update. Some questions I still have after reading that page are

  • is this still going ahead for 3.0, or is it maybe just forgotten and out-of-date?
  • how can it be used? I can’t quite imagine a non-macro-like implementation.
  • an example snippet or two of it being used with a real implementation
  • maybe an example of a scenario where this provides value and one might want to use this in their code

Thank you!


ping @milessabin @odersky :slight_smile:


It is as described on the doc page. I agree it would be good to add more documentation to it. I won’t have time to do it, but if someone else steps up, that would be great.

Here’s some usage of AnyKind I saw in the wild. With macros…