mercurial/pure/parsers.py

--- a/mercurial/pure/parsers.py	Mon Aug 20 16:13:17 2018 -0400
+++ b/mercurial/pure/parsers.py	Sat Aug 18 00:01:31 2018 -0700
@@ -47,7 +47,7 @@
     def _fix_index(self, i):
         if not isinstance(i, int):
             raise TypeError("expecting int indexes")
-        if i < 0 or i >= len(self) + 1:
+        if i < 0 or i >= len(self):
             raise IndexError
         return i