[GHC] #13105: Allow type families in RuntimeReps

[GHC]

#13105: Allow type families in RuntimeReps
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        Reporter:  goldfire          |                Owner:
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.0.1
      Resolution:                    |             Keywords:
                                     |  LevityPolymorphism
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
                                     |  typecheck/should_fail/T13105
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by simonpj):

 > When that kind is TYPE (RepRep Int), the code generator throws up its
 arms in despair.

 So presumably the Lint check that every argument is not levity-polymorphic
 fails?  Actually seeing the code fragment would be helpful.

 Assuming it's a Lint failure (which I think it could be), can't the type
 checker just normalise before spitting out the argument code?

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13105#comment:3>
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