rustc_allowed_through_unstable_modules: require deprecation message This changes the `#[rustc_allowed_through_unstable_modules]` attribute so that a deprecation message (ideally directing people towards the stable path) is required.
rustc_allowed_through_unstable_modules: require deprecation message This changes the `#[rustc_allowed_through_unstable_modules]` attribute so that a deprecation message (ideally directing people towards the stable path) is required.