After installing Rust on OS X via the dmg I had trouble getting the bash autocompletion to work (perhaps I should have used brew install instead).
Anyway I went ahead and made my own autocompletions. In case it's useful to anyone else it's at GitHub - arikast/askbash: An intuitive yaml-driven bash auto-completion framework
I'm new to Rust so my definitions were just based on what was displayed by the -h help pages. If anything seems off let me know and I'll fix.