A compliant implementation has no unimplemented features? And a non-compliant implementation can warn for missing features in a hardcoded way. Why should the standard library use it and why should it be in the standard? -----Ursprüngliche Nachricht----- Von:Hans Åberg via Std-Proposals <std-proposals_at_[hidden]> > > The most common use will not the in the Standard Library. Please design it > with the most common use-case in mind. The intended design is for use in the standard library.