[GHC] #13267: Constraint synonym instances

[GHC]

#13267: Constraint synonym instances
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        Reporter:  ezyang            |                Owner:
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler (Type    |              Version:  8.1
  checker)                           |
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  GHC accepts       |  Unknown/Multiple
  invalid program                    |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by rwbarton):

 This is a duplicate of some other ticket. As I recall, the problem here is
 that the renamer wants to resolve the name `show` to a method of a
 particular class, at a point before we can normalize the type `ShowF`.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13267#comment:3>
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