diff -r c2537aec3bb6 -r 7ed4c4753891 mercurial/simplemerge.py
--- a/mercurial/simplemerge.py	Tue Jan 11 22:13:56 2022 -0800
+++ b/mercurial/simplemerge.py	Fri Jan 14 08:44:36 2022 -0800
@@ -27,10 +27,6 @@
 from .utils import stringutil
 
 
-class CantReprocessAndShowBase(Exception):
-    pass
-
-
 def intersect(ra, rb):
     """Given two ranges return the range where they intersect or None.