Regression: rebase -C1 fails in master

[Phillip Wood <phillip.wood@xxxxxxxxxxxx>]

I've just tried running

bin-wrappers/git rebase -C1 @^

and I get

error: unknown switch `1'
usage: git rebase [-i] [options] [--exec <cmd>] [--onto <newbase>]
[<upstream>] [<branch>]
   or: git rebase [-i] [options] [--exec <cmd>] [--onto <newbase>]
--root [<branch>]
   or: git rebase --continue | --abort | --skip | --edit-todo
...

bin-wrappers/git --version gives
git version 2.19.1.856.g8858448bb4

Unfortunately I've not got time it investigate properly at the moment.

Best Wishes

Phillip