[GHC] #10494: Representational equalities over AppTys are not hard failures

[GHC]

#10494: Representational equalities over AppTys are not hard failures
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        Reporter:  goldfire          |                Owner:
            Type:  bug               |               Status:  merge
        Priority:  high              |            Milestone:  7.10.3
       Component:  Compiler          |              Version:
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
                                     |  typecheck/should_compile/T10494
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by bgamari):

 goldfire, I've committed more head-scratching to porting this forward that
 perhaps I should have. Do you suppose you could port this to 7.10 (perhaps
 using `ghc-7.10.2-release` as a base commit)?

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10494#comment:12>
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