It doesn't [look like it](https://github.com/bbatsov/ruby-style-guide#exceptions). I think you should use `raise` and not `fail` though when you intend to `raise` an exception that could/should be rescued. But if you just want to stop/halt/fail, then you would use `fail` with a message. In other words, I would recommend against using `fail` with an exception and vice versa although I'm not 100% sure if rubocop checks the former.