[commit: ghc] master: Drop custom mapM impl for [] (6029748)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/ghc

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/60297486fddd5c9695e2263c2ae46fa90f0feb9e/ghc

>---------------------------------------------------------------

commit 60297486fddd5c9695e2263c2ae46fa90f0feb9e
Author: Ben Gamari <bgamari.foss at gmail.com>
Date:   Wed Aug 5 14:21:47 2015 +0200

    Drop custom mapM impl for []
    
    See https://mail.haskell.org/pipermail/libraries/2015-May/025708.html
    for motivation.
    
    This fixes #10457
    
    Test Plan: Validate
    
    Reviewers: hvr, austin
    
    Subscribers: simonmar, thomie, dolio
    
    Differential Revision: https://phabricator.haskell.org/D1124
    
    GHC Trac Issues: #10457


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60297486fddd5c9695e2263c2ae46fa90f0feb9e
 libraries/base/Data/Traversable.hs | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/libraries/base/Data/Traversable.hs b/libraries/base/Data/Traversable.hs
index 1d3ef93..535db00 100644
--- a/libraries/base/Data/Traversable.hs
+++ b/libraries/base/Data/Traversable.hs
@@ -56,7 +56,6 @@ import Data.Proxy ( Proxy(..) )
 import GHC.Arr
 import GHC.Base ( Applicative(..), Monad(..), Monoid, Maybe(..),
                   ($), (.), id, flip )
-import qualified GHC.Base as Monad ( mapM )
 import qualified GHC.List as List ( foldr )
 
 -- | Functors representing data structures that can be traversed from
@@ -180,8 +179,6 @@ instance Traversable [] where
     traverse f = List.foldr cons_f (pure [])
       where cons_f x ys = (:) <$> f x <*> ys
 
-    mapM = Monad.mapM
-
 instance Traversable (Either a) where
     traverse _ (Left x) = pure (Left x)
     traverse f (Right y) = Right <$> f y