[GHC] #13117: Derived functor instance for void types handles errors badly

[GHC]

#13117: Derived functor instance for void types handles errors badly
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        Reporter:  dfeuer            |                Owner:  dfeuer
            Type:  feature request   |               Status:  new
        Priority:  normal            |            Milestone:  8.2.1
       Component:  Compiler          |              Version:  8.0.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #7401             |  Differential Rev(s):
       Wiki Page:                    |
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Changes (by RyanGlScott):

 * related:   => #7401


Comment:

 The discussion is at #7401, which proposed an overhaul of the way derived
 instances for void types work. Ultimately, a consensus was never reached
 as to how derived `Eq` instances should work. See
 https://ghc.haskell.org/trac/ghc/ticket/7401#comment:46.

 If someone would be willing revive that discussion and advocate for a
 position, I'd be very appreciative, as I'm hesitant to poke that sleeping
 dragon again :)

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13117#comment:3>
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