diff -r 67964cda8701 -r e34106fa0dc3 mercurial/simplemerge.py
--- a/mercurial/simplemerge.py	Sat May 12 16:00:57 2012 +0200
+++ b/mercurial/simplemerge.py	Sat May 12 16:00:58 2012 +0200
@@ -94,7 +94,7 @@
             elif self.a[0].endswith('\r'):
                 newline = '\r'
         if base_marker and reprocess:
-            raise CantReprocessAndShowBase()
+            raise CantReprocessAndShowBase
         if name_a:
             start_marker = start_marker + ' ' + name_a
         if name_b: