diff -r 6754d0c5e1b5 -r 418f9ea20c35 mercurial/policy.py
--- a/mercurial/policy.py	Sat Mar 03 07:59:20 2018 -0500
+++ b/mercurial/policy.py	Sat Mar 03 05:51:34 2018 -0500
@@ -44,11 +44,6 @@
 if r'__pypy__' in sys.builtin_module_names:
     policy = b'cffi'
 
-# Our C extensions aren't yet compatible with Python 3. So use pure Python
-# on Python 3 for now.
-if sys.version_info[0] >= 3:
-    policy = b'py'
-
 # Environment variable can always force settings.
 if sys.version_info[0] >= 3:
     if r'HGMODULEPOLICY' in os.environ: