[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
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Comment (by RyanGlScott):

 Replying to [comment:23 hvr]:
 > Somewhat related, #10930 wants GHC to at least emit a compiler warning
 in that case

 Ah, that's good to know. Perhaps we could add a similar warning for `[] ::
 NonEmpty` (when using `-XOverloadedLists`) in one of the phases of this
 proposal.

 While we're on this topic, I have another questions about things to come
 from the SMP (`Semigroup`–`Monoid` Proposal). Adding `Data.List.NonEmpty`
 brings in the `First`, `Last`, and `Option` data types, which are
 (intentionally) quite similar in behavior to `First` and `Last` (from
 `Data.Monoid`) and `Maybe`. Are there plans to consolidate (or
 strategically deprecate) some of these data types at some phase of the
 SMP?

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10365#comment:24>
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