Rocket publishes a library that requires nightly features to work because the alternative is not publishing the library that requires nightly features to work. I'm not sure what you think you're losing by the library existing on crates.io, but there really isn't a way of doing what rocket does without nightly. If there were, Rocket would be doing it (and stabilization for its features is fast approaching).

Thanks. It’s always good to know. I rarely run into this anymore, so different perspectives are useful.

(Rocket’s master branch doesn’t require nightly but they haven’t released yet, incidentally.)