{"ast_node_type":"other","tokens":[{"end":90,"kind":"keyword","start":0,"text":"//"}]}
// This is `pub` for rustdoc. rustc should call it through `check_mod_unstable_api_usage`.
/// libraries, identify activated features that don't exist and error about them.
pub fn check_unused_or_stable_features(tcx: TyCtxt<'_>) {