[GHC] #8004: Applicative/Monad proposal related warnings (AMP phase 1)

[GHC]

#8004: Applicative/Monad proposal related warnings (AMP phase 1)
-------------------------------------+-------------------------------------
        Reporter:  quchen            |                Owner:  quchen
            Type:  feature request   |               Status:  closed
        Priority:  high              |            Milestone:  7.8.1
       Component:  Compiler          |              Version:  7.6.3
      Resolution:  fixed             |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #4834             |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by Ben Gamari <ben@…>):

 In [changeset:"290def72f54db7969258b4541aaefc87b54ce448/ghc"
 290def72/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="290def72f54db7969258b4541aaefc87b54ce448"
 Implement warnings for Semigroups as parent of Monoid

 This patch is similar to the AMP patch (#8004), which offered two
 functions:

   1. Warn when an instance of a class has been given, but the type does
      not have a certain superclass instance
   2. Warn when top-level definitions conflict with future Prelude names

 These warnings are issued as part of the new `-Wcompat` warning group.

 Reviewers: hvr, ekmett, austin, bgamari

 Reviewed By: hvr, ekmett, bgamari

 Subscribers: ekmett, thomie

 Differential Revision: https://phabricator.haskell.org/D1539

 GHC Trac Issues: #11139
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8004#comment:25>
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