Function emit_unused_generic_params_error

fn emit_unused_generic_params_error<'tcx>(
    tcx: TyCtxt<'tcx>,
    def_id: DefId,
    generics: &'tcx Generics,
    unused_parameters: &UnusedGenericParams,
)

Emit errors for the function annotated by #[rustc_polymorphize_error], labelling each generic parameter which was unused.