[GHC] #11714: Kind of (->) type constructor is overly constrained

[GHC]

#11714: Kind of (->) type constructor is overly constrained
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        Reporter:  bgamari           |                Owner:
            Type:  feature request   |               Status:  new
        Priority:  normal            |            Milestone:  8.2.1
       Component:  Compiler          |              Version:  8.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by simonpj):

 Maybe we can have

 *  Saturated applications of arrow, with its own kinding rule.  Actually
 it's represented as `ForAllTy (Anon ty1) ty2` so looks nothing like
 `TyConApp`, and there is no `TyCon` involved.

 * `(->)` with the complicated kind you give above, used for unsaturated
 partial applications.

 Now `splitTyConApp` on a `ForallTy (Anon _) _` would have to add those
 missing kind `RuntimeRep` arguments, but it can do that easily enough.

 Might that get the best of both worlds?

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11714#comment:3>
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