[GHC] #10635: -fwarn-redundant-constraints should not be part of -Wall

[GHC]

#10635: -fwarn-redundant-constraints should not be part of -Wall
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        Reporter:  Lemming           |                Owner:
            Type:  feature request   |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler (Type    |              Version:  7.11
  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:  #9939, #9973,     |  Differential Rev(s):
  #10100, #10183, #11370             |
       Wiki Page:                    |
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Comment (by Lemming):

 Replying to [comment:27 konn]:

 > Example:
 >
 > {{{
 > flipAdd :: (Multiplicative r, {-# NON_REDUNDANT #-} Abelian r) => r -> r
 -> r
 > flipAdd x y = x + y
 > }}}
 >
 > Compiler should warn `Multiplicative r` as redundant since it doesn't
 use any multiplication, but `Abelian r` should be unwarned because it's
 marked as ''non-redundant''.

 I like this approach, too, but I would prefer a positive attribute, e.g.
 `{-# REQUIRED #-}` or `{-# INTENDED #-}`.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10635#comment:28>
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