[GHC] #15625: GHC panic, with QuantifiedConstraints

[GHC]

#15625: GHC panic, with QuantifiedConstraints
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        Reporter:  Iceland_jack      |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.6.1-beta1
      Resolution:                    |             Keywords:
                                     |  QuantifiedConstraints
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by monoidal):

 Simpler version that also gives Core Lint warning:

 {{{
 {-# Language GADTs, MultiParamTypeClasses, QuantifiedConstraints #-}

 class a ~ b => Equal a b

 ekki__ :: (forall b. Equal a b) => a
 ekki__ = False
 }}}

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15625#comment:3>
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