[GHC] #12959: GHC doesn't warn about missing implementations for class methods beginning with an underscore

[GHC]

#12959: GHC doesn't warn about missing implementations for class methods beginning
with an underscore
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        Reporter:  RyanGlScott       |                Owner:
            Type:  bug               |               Status:  patch
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.0.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  Other             |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):  Phab:D2849
       Wiki Page:                    |
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Comment (by bgamari):

 It's not clear how this behavior was arrived at but I agree that at first
 glance it doesn't seem desirable.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12959#comment:6>
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