[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 Lemming):

 Replying to [comment:31 ekmett]:
 > The moral equivalent in `Semigroup` requires some form of canonical non-
 empty type to fold over. The net effect of removing it is that the
 `semigroups` package would continue to exist just to supply this type, the
 class would lose its canonical structure to fold over, and `sconcat`
 becomes unimplementable.

 `sconcat` in base could have type `s -> [s] -> s`. Then there is no need
 for `NonEmpty` to be in `base` and people can define top-level functions
 that use `sconcat` to implement a counterpart for their favourite
 `NonEmpty` type (e.g. `Data.List.NonEmpty` or `Data.NonEmpty`).

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10365#comment:32>
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