[GHC] #9586: Implement Traversable/Foldable-Burning-Bridges Proposal

[GHC]

#9586: Implement Traversable/Foldable-Burning-Bridges Proposal
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              Reporter:  hvr         |            Owner:  hvr
                  Type:  task        |           Status:  new
              Priority:  normal      |        Milestone:  7.10.1
             Component:              |          Version:
  libraries/base                     |         Keywords:
            Resolution:              |     Architecture:  Unknown/Multiple
      Operating System:              |       Difficulty:  Difficult (2-5
  Unknown/Multiple                   |  days)
       Type of failure:              |       Blocked By:
  None/Unknown                       |  Related Tickets:  #9621
             Test Case:              |
              Blocking:              |
Differential Revisions:  Phab:D209   |
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Comment (by Herbert Valerio Riedel <hvr@…>):

 In [changeset:"b8f583928fa6cb5371a872fc73080d2002dd87d9/ghc"]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="b8f583928fa6cb5371a872fc73080d2002dd87d9"
 Export `Monoid(..)`/`Foldable(..)`/`Traversable(..)` from Prelude

 This finally exposes also the methods of these 3 classes in the Prelude
 in order to allow to define basic class instances w/o needing imports.

 This almost completes the primary goal of #9586

 NOTE: `fold`, `foldl'`, `foldr'`, and `toList` are not exposed yet,
       as they require upstream fixes for at least `containers` and
       `bytestring`, and are not required for defining basic instances.

 Reviewed By: ekmett, austin

 Differential Revision: https://phabricator.haskell.org/D236
 }}}

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9586#comment:18>
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