From: Ian Lynagh <igloo@earth.li>
Date: Mon, 4 Aug 2008 16:09:41 +0000 (+0000)
Subject: Generalise the type of mapException; pointed out by Isaac Dupree
X-Git-Tag: 6_10_branch_has_been_forked~86
X-Git-Url: http://git.megacz.com/?a=commitdiff_plain;h=0598083cfccabdb9064c259c698d05fc79fc1a9e;p=ghc-base.git

Generalise the type of mapException; pointed out by Isaac Dupree
---

diff --git a/Control/Exception.hs b/Control/Exception.hs
index b3638f6..812c165 100644
--- a/Control/Exception.hs
+++ b/Control/Exception.hs
@@ -358,7 +358,7 @@ handleJust p =  flip (catchJust p)
 
 -- Notice that the usage of 'unsafePerformIO' is safe here.
 
-mapException :: Exception e => (e -> e) -> a -> a
+mapException :: (Exception e1, Exception e2) => (e1 -> e2) -> a -> a
 mapException f v = unsafePerformIO (catch (evaluate v)
                                           (\x -> throw (f x)))