[GHC] #14958: QuantifiedConstraints: Doesn't apply implication for existential?

[GHC]

#14958: QuantifiedConstraints: Doesn't apply implication for existential?
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        Reporter:  Iceland_jack      |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.5
      Resolution:                    |             Keywords:
                                     |  QuantifiedConstraints, wipT2893
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 simonpj):

 >  I have a draft ready for an overview of this extension from
 ticket:14840#comment:6, should I email it to you?

 A draft of what?  A blog post?  If so, I suggest you just post it!

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14958#comment:3>
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