[GHC] #10859: Generated Eq instance associates && wrongly

[GHC]

#10859: Generated Eq instance associates && wrongly
-------------------------------------+-------------------------------------
        Reporter:  nomeata           |                Owner:  simonpj
            Type:  bug               |               Status:  patch
        Priority:  lowest            |            Milestone:
       Component:  Compiler          |              Version:  7.10.2
      Resolution:                    |             Keywords:  deriving,
                                     |  newcomer
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #10858            |  Differential Rev(s):  Phab:D5104
       Wiki Page:                    |
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Comment (by Krzysztof Gogolewski <krz.gogolewski@…>):

 In [changeset:"2d953a60489ba30433e5f2fe27c50aa9da75f802/ghc" 2d953a6/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="2d953a60489ba30433e5f2fe27c50aa9da75f802"
 Fix #10859 by using foldr1 while deriving Eq instances

 Summary:
 Previously, we were using foldl1 instead, which led to the derived
 code to be wrongly associated.

 Test Plan: ./validate

 Reviewers: RyanGlScott, nomeata, simonpj, bgamari

 Reviewed By: RyanGlScott, nomeata

 Subscribers: rwbarton, carter

 GHC Trac Issues: #10859

 Differential Revision: https://phabricator.haskell.org/D5104
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10859#comment:5>
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