[GHC] #8090: MetaKinds - PolyKinds generalization

[GHC]

#8090: MetaKinds - PolyKinds generalization
------------------------------------+-------------------------------------
       Reporter:  wvv               |             Owner:
           Type:  feature request   |            Status:  new
       Priority:  normal            |         Milestone:
      Component:  Compiler          |           Version:  7.6.3
       Keywords:                    |  Operating System:  Unknown/Multiple
   Architecture:  Unknown/Multiple  |   Type of failure:  None/Unknown
     Difficulty:  Unknown           |         Test Case:
     Blocked By:                    |          Blocking:
Related Tickets:                    |
------------------------------------+-------------------------------------
 MetaKinds is more general then PolyKinds.

 Now we could write with PolyKinds

 {{{
 class Foo (a :: k) where ...
 }}}

 It would be nice if we could also write with MetaKinds next:

 {{{
 class Foo (a :: (k :: *)) where ...
 }}}

 As we already have Rank2Types and RankNTypes,

 PolyKinds ~ Rank2Types,

 MetaKinds ~ RankNTypes

 This will be valid:
 {{{
 class Foo (a :: (k :: (u :: *))) where ...
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8090>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler