Previous mentions of the "std::span lacks size_type" issue:

https://stackoverflow.com/questions/55209261/why-does-stdspan-lack-size-type
http://lists.isocpp.org/std-proposals/2019/05/0019.php

I believe it's just one of those cases where "everyone knows this is a bug, but WG21 isn't willing to fix it without a paper or a National Body comment."

–Arthur

On Sun, Jun 30, 2019 at 10:51 AM Andrey Semashev via Std-Proposals <std-proposals@lists.isocpp.org> wrote:

Hi,

Looking at the std::span interface definition in N4820 I'm wondering why
there is no size_type type definition? This type is commonly used to get
the size type of a range or container in the users' code, so why is span
made incompatible?
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