[GHC] #16276: Feature request: Polymorphic kinds in Data.Functor.Classes

[GHC]

#16276: Feature request: Polymorphic kinds in Data.Functor.Classes
-------------------------------------+-------------------------------------
           Reporter:  siddharthist   |             Owner:  (none)
               Type:  feature        |            Status:  new
  request                            |
           Priority:  normal         |         Milestone:
          Component:  Compiler       |           Version:  8.6.3
           Keywords:  polykinds      |  Operating System:  Unknown/Multiple
       Architecture:                 |   Type of failure:  None/Unknown
  Unknown/Multiple                   |
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
-------------------------------------+-------------------------------------
 The classes in Data.Functor.Classes have a somewhat restrictive kind
 signature:
 {{{
 *Data.Functor.Classes> :k Eq1
 Eq1 :: (* -> *) -> Constraint
 }}}

 As a result, we redefine [1] many of them in the
 [https://hackage.haskell.org/package/parameterized-utils-1.0.1/docs/Data-
 Parameterized-Classes.html parameterized-utils] library. It would be quite
 easy to make more polymorphic (have kind "(k -> *) -> Constraint"). If
 everyone thinks this is a good idea, I'm happy to submit a pull request.

 [1]: To be precise, there are actually a few axes along which the classes
 in parameterized-utils vary from those in base. Some, like OrdF, require
 more type-level evidence. Others, like EqF, don't require their type
 parameter to have the corresponding instance. There are a lot of points in
 the design space here.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/16276>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler