[GHC] #15831: DerivingVia allows bogus implicit quantification in `via` type

[GHC]

#15831: DerivingVia allows bogus implicit quantification in `via` type
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        Reporter:  RyanGlScott       |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.10.1
       Component:  Compiler          |              Version:  8.6.1
      Resolution:                    |             Keywords:  deriving
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Poor/confusing    |  Unknown/Multiple
  error message                      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #16181            |  Differential Rev(s):
       Wiki Page:                    |
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Changes (by RyanGlScott):

 * related:   => #16181


Comment:

 #16181 is likely a symptom of this ticket.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15831#comment:3>
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