diff --git a/hgext/rebase.py b/hgext/rebase.py
--- a/hgext/rebase.py
+++ b/hgext/rebase.py
@@ -538,7 +538,7 @@
                     user=ctx.user(),
                     date=date,
                 )
-                mergestatemod.mergestate.clean(repo)
+                self.wctx.mergestate(clean=True)
             else:
                 newnode = commitnode(
                     repo,