[GHC] #13813: DeriveFunctor spuriously rejects existential context with type synonym mentioning the last type variable

[GHC]

#13813: DeriveFunctor spuriously rejects existential context with type synonym
mentioning the last type variable
-------------------------------------+-------------------------------------
        Reporter:  RyanGlScott       |                Owner:  (none)
            Type:  bug               |               Status:  patch
        Priority:  normal            |            Milestone:
       Component:  Compiler (Type    |              Version:  8.0.1
  checker)                           |
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  GHC rejects       |  Unknown/Multiple
  valid program                      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):  Phab:D3635
       Wiki Page:                    |
-------------------------------------+-------------------------------------
Changes (by RyanGlScott):

 * status:  new => patch
 * differential:   => Phab:D3635


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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13813#comment:1>
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