Function rustc::middle::stability::check_unused_or_stable_features

pub fn check_unused_or_stable_features<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>)

🔬 This is a nightly-only experimental API. (rustc_private)

this crate is being loaded from the sysroot, an unstable location; did you mean to load this crate from crates.io via Cargo.toml instead?

Given the list of enabled features that were not language features (i.e. that were expected to be library features), and the list of features used from libraries, identify activated features that don't exist and error about them.