Sorry, I think I confused you, please post that patch here. This issue is for documenting the workarounds, issue 9338 is for actually solving the problem.
I glanced at your patch on that issue, and it looks basically okay, though I'd like to see a few more tests for the help messages to cover things like:
-x X A # no --
-x [X [X ...]] -y Y [Y ...] # no --
-x [X] -- A B # needs --
-x X [X ...] # needs --
-x [X [X ...]] # needs --
It's possible the first two are already covered by the other tests, but at least the last three should all be tested for.