[commit: packages/containers] ghc-head: Optimize Map.foldMapWithKey. (e60634d)

[git at git.haskell.org]

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

On branch  : ghc-head
Link       : http://git.haskell.org/?p=packages/containers.git;a=commit;h=e60634d138fe1170899678f4e5d7bf42c388fae8

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

commit e60634d138fe1170899678f4e5d7bf42c388fae8
Author: Milan Straka <fox at ucw.cz>
Date:   Tue Jul 2 21:25:31 2013 +0200

    Optimize Map.foldMapWithKey.
    
    Use optimalizations from foldMap and traverseWithKey -- associativity
    and test for leaves.


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

e60634d138fe1170899678f4e5d7bf42c388fae8
 Data/Map/Base.hs |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/Data/Map/Base.hs b/Data/Map/Base.hs
index 4a1600d..fa2fa6a 100644
--- a/Data/Map/Base.hs
+++ b/Data/Map/Base.hs
@@ -1884,7 +1884,8 @@ foldMapWithKey :: Monoid m => (k -> a -> m) -> Map k a -> m
 foldMapWithKey f = go
   where
     go Tip             = mempty
-    go (Bin _ k v l r) = go l `mappend` f k v `mappend` go r
+    go (Bin 1 k v _ _) = f k v
+    go (Bin _ k v l r) = go l `mappend` (f k v `mappend` go r)
 {-# INLINE foldMapWithKey #-}
 
 {--------------------------------------------------------------------