[commit: base] master: Use fromException instead of cast when matching exceptions (23d7c26)

[Simon Marlow]

Repository : ssh://darcs.haskell.org//srv/darcs/packages/base

On branch  : master

http://hackage.haskell.org/trac/ghc/changeset/23d7c26d57bb1f8d82acde15f224ff53bca766a9

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

commit 23d7c26d57bb1f8d82acde15f224ff53bca766a9
Author: Simon Marlow <marlowsd at gmail.com>
Date:   Thu Feb 7 09:00:22 2013 +0000

    Use fromException instead of cast when matching exceptions
    
    Since I added the SomeAsyncException class, we weren't calling the
    StackOverflowHook() properly for stack overflows, because this bit of
    code was not expecting the extra layer in the hierarchy.

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

 GHC/TopHandler.lhs |    8 ++++----
 1 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/GHC/TopHandler.lhs b/GHC/TopHandler.lhs
index f1b0cbf..160b8d1 100644
--- a/GHC/TopHandler.lhs
+++ b/GHC/TopHandler.lhs
@@ -148,22 +148,22 @@ topHandlerFastExit err =
 --  another error, etc.)
 --
 real_handler :: (Int -> IO a) -> SomeException -> IO a
-real_handler exit se@(SomeException exn) = do
+real_handler exit se = do
   flushStdHandles -- before any error output
-  case cast exn of
+  case fromException se of
       Just StackOverflow -> do
            reportStackOverflow
            exit 2
 
       Just UserInterrupt  -> exitInterrupted
 
-      _ -> case cast exn of
+      _ -> case fromException se of
            -- only the main thread gets ExitException exceptions
            Just ExitSuccess     -> exit 0
            Just (ExitFailure n) -> exit n
 
            -- EPIPE errors received for stdout are ignored (#2699)
-           _ -> case cast exn of
+           _ -> case fromException se of
                 Just IOError{ ioe_type = ResourceVanished,
                               ioe_errno = Just ioe,
                               ioe_handle = Just hdl }