[GHC] #11370: Redundant superclass warnings being included in -Wall destroys the "3 Release Policy"

[GHC]

#11370: Redundant superclass warnings being included in -Wall destroys the "3
Release Policy"
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        Reporter:  ekmett            |                Owner:
            Type:  bug               |               Status:  new
        Priority:  highest           |            Milestone:  8.0.1
       Component:  Compiler (Type    |              Version:  7.10.3
  checker)                           |
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Incorrect         |  Unknown/Multiple
  warning at compile-time            |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #11369, #11429    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by simonmar):

 It's perfectly fine for `-Wall` to contain warnings that sometimes need to
 be disabled, for reasons of personal taste or necessity.  A lot of our
 code has `-Wall -fno-warn-unused-do-binds -fno-warn-name-shadowing`, and
 it's quite often necessary to throw in a `-fno-warn-orphans` when there's
 no reasonable way to avoid an orphan.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11370#comment:31>
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