What are uses of polymorphic kinds?

Question

Polymorphic kinds are an extension to Haskell\'s type system, supported by UHC, allowing

data A x y = A (y x)

to be typed (kinded?) as a

Answer 1

Adding Polymorphic Kinds to GHC

The background to this question would be the motivation in general for a more expressive kind system.

That is, the overall reason to add polymorphic kinds to Haskell is to improve the experience of type level programming. Currently type level programming in Haskell proceeds in a essentially untyped "kind" level. A richer kind language will make type level programming in Haskell, in general, easier.

A more concrete example would be to remove the (dynamic) Typeable constraint from generics of the SYB style (citation), as well as improving overall support for higher-kinded generic programming..