[GHC] #10365: Implement Semigroup as a superclass of Monoid Proposal (Phase 1)

[GHC]

#10365: Implement Semigroup as a superclass of Monoid Proposal (Phase 1)
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        Reporter:  gidyn             |                Owner:  quchen
            Type:  feature request   |               Status:  patch
        Priority:  high              |            Milestone:  8.0.1
       Component:  libraries/base    |              Version:  7.10.1
      Resolution:                    |             Keywords:  report-impact
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):  Phab:D1284
       Wiki Page:                    |
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Comment (by rwbarton):

 You can rename the method of `Semigroup` with type `a -> [a] -> a` and
 move `sconcat` to a top-level definition in `Data.List.NonEmpty`, and that
 should hardly break anyone compared to the rather substantial `Semigroup
 => Monoid` superclass addition that is the main part of this proposal.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10365#comment:39>
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