On Mon, Feb 2, 2026 at 2:11 PM JJ Marr <jjmarr_at_[hidden]> wrote:
>
> > The question of whether `substr` should be a `const` function is a
> "yes/no" question. One of those answers is correct.
>
> Off-topic, but can it be `constexpr` at least?

`constexpr` member functions don't have fewer requirements than
`const` member functions, but that would be reasonable too. And in
P3655, it is `contexpr`.