Comment 5 for bug 6700

I think I'd rather just take the git syntax, including the -- separator. Why?

You can usefully do a selected file diff without specifying both the paths. If we rely on them being the last two then you cannot do that.

Having just done a diff it might be nice to cursor up and add a filename to filter it. (Not a very strong argument.)

Is there any particular reason to put them at the start?