[GHC] #15921: Data.List.maximumBy uses counter-intuitive ordering

[GHC]

#15921: Data.List.maximumBy uses counter-intuitive ordering
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        Reporter:  qqwy              |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.6.2
      Resolution:                    |             Keywords:  List
                                     |  maximumBy minimumBy
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by qqwy):

 >  There are local minBy/maxBy functions in the implementation that treat
 the EQ case differently. That does not feel consistent with the "laws for
 Ord that are expected to hold" (where EQ would always select the first
 argument)

 This is what the problem distills do, and what I feel should be changed
 (instead making the implementations of the `min'` and `max'` local to
 `minBy/maxBy` align with the behaviour of the public `min` and `max`).

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15921#comment:5>
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