[commit: ghc] master: Set default-impl of `mapM`/`sequence` methods to `traverse`/`sequenceA` (f636faa)

[git at git.haskell.org]

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

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/f636faa7b2b7fc1d0663f994ad08f365d39a746d/ghc

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

commit f636faa7b2b7fc1d0663f994ad08f365d39a746d
Author: Herbert Valerio Riedel <hvr at gnu.org>
Date:   Sat Sep 27 22:55:19 2014 +0200

    Set default-impl of `mapM`/`sequence` methods to `traverse`/`sequenceA`
    
    This is made possible by the AMP, as we don't need the `WrappedMonad`
    helper for that anymore.
    
    Approved-by: Edward Kmett <ekmett at gmail.com>


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

f636faa7b2b7fc1d0663f994ad08f365d39a746d
 libraries/base/Data/Traversable.hs | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/libraries/base/Data/Traversable.hs b/libraries/base/Data/Traversable.hs
index eb5123d..1c8b605 100644
--- a/libraries/base/Data/Traversable.hs
+++ b/libraries/base/Data/Traversable.hs
@@ -46,7 +46,7 @@ module Data.Traversable (
     foldMapDefault,
     ) where
 
-import Control.Applicative ( Const(..), WrappedMonad(..) )
+import Control.Applicative ( Const(..) )
 import Data.Either ( Either(..) )
 import Data.Foldable ( Foldable )
 import Data.Functor
@@ -157,12 +157,12 @@ class (Functor t, Foldable t) => Traversable t where
     -- | Map each element of a structure to a monadic action, evaluate
     -- these actions from left to right, and collect the results.
     mapM :: Monad m => (a -> m b) -> t a -> m (t b)
-    mapM f = unwrapMonad . traverse (WrapMonad . f)
+    mapM = traverse
 
     -- | Evaluate each monadic action in the structure from left to right,
     -- and collect the results.
     sequence :: Monad m => t (m a) -> m (t a)
-    sequence = mapM id
+    sequence = sequenceA
     {-# MINIMAL traverse | sequenceA #-}
 
 -- instances for Prelude types