On Mon, Jul 1, 2019 at 4:21 PM Nevin Liber via Std-Proposals <std-proposals@lists.isocpp.org> wrote:

• Why any value at all?  Last I checked, we now have variadic templates, where "now" is defined as since 2011...

template <typename T, std::size_t Extent>

void some_function(std::span<T, Extent> some_span) { ... }

As currently specified, this function accepts any span of any extent, static or dynamic. Using a variadic template breaks this,

and there would be no easy way to write a function taking both kinds of span.