You're the one misunderstanding here. The reference implementation that they provided (which I actually believe is gsl::span) allows configuration. The design f

You're the one misunderstanding here. The reference implementation that they provided (which I actually believe is gsl::span) allows configuration. The design for the standard, as you have mentioned elsewhere in this discussion, does not provide bounds checking. I am making a big deal out of this because it is a problem that affects real codebases, not something hypothetical that you can wave away with your idea of how things work. The fact is that people who care about security ship non-bounds-checked spans because this is not the default option.