[GHC] #13327: Figure out how to make sense of Data instances for poly-kinded datatypes

[GHC]

#13327: Figure out how to make sense of Data instances for poly-kinded datatypes
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        Reporter:  RyanGlScott       |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  libraries/base    |              Version:  8.0.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #4028             |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by RyanGlScott):

 Edward Kmett laid out an interesting (albeit not terribly practical)
 proposal for cleaning up the current story in
 https://mail.haskell.org/pipermail/ghc-devs/2017-February/013850.html.
 Sadly, his code doesn't actually typecheck due to what I believe is a
 corollary of #13337.

 I came up with an even grosser proposal in
 https://mail.haskell.org/pipermail/ghc-devs/2017-February/013852.html that
 //does// typecheck, but with emphasis on the "even grosser" part. There's
 certainly no way I'd want `Data.Data` to adopt that approach as-is.

 I need to think more on how I can take the programming patterns in these
 two proposals and clean them up into something palatable.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13327#comment:3>
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