Hey there. I've got a library that I'd like to release to support two flavours of the toolchain: stable and nightly. When using stable, I'd like to use the async-trait library. When using nightly, I'd like to enable the async-trait functionality found in nightly. I'm thinking of having a default std feature that'd bring in the async-trait lib etc.
Caution: this can result in a library which stops compiling when nightly changes (a feature is changed, or a feature flag is removed because the feature has been stabilized), even if the user of the library doesn't need the nightly-only functionality of the library but is compiling on nightly for other reasons.