From: Ian Lynagh <igloo@earth.li>
Date: Sun, 3 Aug 2008 00:30:01 +0000 (+0000)
Subject: Generalise the type of onException
X-Git-Tag: 6_10_branch_has_been_forked~100
X-Git-Url: http://git.megacz.com/?a=commitdiff_plain;h=f3b6c6b77f1667164913725dcfe12f64b9e99f74;p=ghc-base.git

Generalise the type of onException
The type of the thing to do on an exception is now
    IO b
rather than
    IO ()
which better matches functions like bracket.
---

diff --git a/Control/Exception.hs b/Control/Exception.hs
index e8032b7..c1dd408 100644
--- a/Control/Exception.hs
+++ b/Control/Exception.hs
@@ -337,7 +337,7 @@ tryJust p a = do
                         Nothing -> throw e
                         Just b  -> return (Left b)
 
-onException :: IO a -> IO () -> IO a
+onException :: IO a -> IO b -> IO a
 onException io what = io `catch` \e -> do what
                                           throw (e :: SomeException)