--- a/mercurial/cmdutil.py	Sun Mar 11 21:36:28 2018 +0900
+++ b/mercurial/cmdutil.py	Sun Mar 18 12:54:03 2018 +0900
@@ -2358,8 +2358,6 @@
             if subs:
                 subrepoutil.writestate(repo, newsubstate)
 
-        # avoid cycle (TODO: should be removed in default branch)
-        from . import merge as mergemod
         ms = mergemod.mergestate.read(repo)
         mergeutil.checkunresolved(ms)