[GHC] #14190: Typeable imposes seemingly redundant constraints on polykinded instances

[GHC]

#14190: Typeable imposes seemingly redundant constraints on polykinded instances
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        Reporter:  dfeuer            |                Owner:  (none)
            Type:  bug               |               Status:  patch
        Priority:  normal            |            Milestone:  8.4.1
       Component:  Compiler (Type    |              Version:  8.2.1
  checker)                           |
      Resolution:                    |             Keywords:  Typeable
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):  Phab:D4000
       Wiki Page:                    |
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Comment (by dfeuer):

 I guess we really do want `typeRepKind`. Without it, we have no way to get
 the kinds of the pieces once we decompose. This doesn't seem to have been
 considered in the original paper, perhaps because the authors were
 thinking of `TypeInType` only as part of the solution, and not as part of
 the problem. I think we almost certainly want to expand the data
 constructors (probably all of them) to accommodate typereps of kinds. One
 thing I'm rather unclear on is just what information is stored in a
 `TyCon` (most particularly, what a `KindRep` is about) and whether we
 really need all that information in that form in the typerep of a tycon.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14190#comment:11>
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