From: Simon Marlow <marlowsd@gmail.com>
Date: Tue, 8 Jun 2010 08:25:31 +0000 (+0000)
Subject: add an INLINE to the list version of traverse, to enable fusion
X-Git-Url: http://git.megacz.com/?a=commitdiff_plain;h=e74a10138daf9fd70888a1841bd6cc93b9cca9f2;p=ghc-base.git

add an INLINE to the list version of traverse, to enable fusion
---

diff --git a/Data/Traversable.hs b/Data/Traversable.hs
index 0df8bd4..28fa761 100644
--- a/Data/Traversable.hs
+++ b/Data/Traversable.hs
@@ -107,6 +107,7 @@ instance Traversable Maybe where
         traverse f (Just x) = Just <$> f x
 
 instance Traversable [] where
+        {-# INLINE traverse #-} -- so that traverse can fuse
         traverse f = Prelude.foldr cons_f (pure [])
           where cons_f x ys = (:) <$> f x <*> ys