[GHC] #10598: DeriveAnyClass and GND don't work well together

[GHC]

#10598: DeriveAnyClass and GND don't work well together
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        Reporter:  osa1              |                Owner:  RyanGlScott
            Type:  bug               |               Status:  patch
        Priority:  normal            |            Milestone:  8.2.1
       Component:  Compiler          |              Version:  7.11
      Resolution:                    |             Keywords:  Generics
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):  Phab:D2280
       Wiki Page:                    |
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Comment (by oerjan):

 Still a few comments:

 * I ''really'' don't think `Enum` belongs in 2(b), which is why I put a
 question mark on it in the first place. I think it should also be moved to
 the bottom left cell in the table.
 * Even though it's explained below, I have a hunch the phrase "bespoke
 typeclass instance" could be misinterpreted as referring to the selected
 strategy. It's a little longer, but "instance for a bespoke typeclass"
 feels less ambiguous.
 * The paragraph starting "Step 2.(b) deserves some explanation." doesn't
 make sense with the new algorithm, since the issue no longer applies with
 the new control flow. (After all, one of the things simplifying it is that
 step 2 doesn't need to consider anyclass any more, and step 3 doesn't need
 to consider bespoke.)

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10598#comment:46>
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