@Andreas Sinz not that I'm aware of. Many interesting typeclasses are not that useful unless HKTs are supported. But HKTs would be also extremely helpful in OOP contexts for code reuse etc. KEEPs seem more recommendations than a part of a process for what I can tell. I have no visibility as to what Jetbrains thinks of KEEP-87 and not even sure what next steps are to get that rolling. In whatever case I'd be happy to help on a HKTs lengthier proposal or expand on KEEP-87 to get it all in at once since they are a tightly coupled feature.