[GHC] #16385: Lousy error message for `instance forall c. c`

[GHC]

#16385: Lousy error message for `instance forall c. c`
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        Reporter:  RyanGlScott       |                Owner:  (none)
            Type:  bug               |               Status:  patch
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.6.3
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Poor/confusing    |  Unknown/Multiple
  error message                      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |  https://gitlab.haskell.org/ghc/ghc/merge_requests/483
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Changes (by RyanGlScott):

 * status:  new => patch
 * differential:   => https://gitlab.haskell.org/ghc/ghc/merge_requests/483


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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/16385#comment:1>
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