hgext/rebase.py

--- a/hgext/rebase.py	Sat Jun 17 23:09:39 2017 -0700
+++ b/hgext/rebase.py	Sat Jun 17 23:09:47 2017 -0700
@@ -1265,7 +1265,7 @@
                 samebranch = root.branch() == wctx.branch()
             else:
                 samebranch = root.branch() == dest.branch()
-            if not collapse and samebranch and root in dest.children():
+            if not collapse and samebranch and dest in root.parents():
                 # mark the revision as done by setting its new revision
                 # equal to its old (current) revisions
                 state[root.rev()] = root.rev()