On Wed, 24 Jan 2024 at 15:37, Jan Schultke via Std-Proposals <
std-proposals_at_[hidden]> wrote:

> This has already been proposed in P1046: Automatically Generate More
> Operators, although with explicit = default. It didn't go further than
> allowing defaulting ->.
>
> https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2020/p1046r2.html
>
> I like the idea, but a strong reason against it is that you can also
> default operator++(int) in terms of operator+, with no prefix
> increment involved. You'd have to make a very strong case for
> hardcoding a specific implementation in the core language instead of
> letting the user decide.
>

Doing it that way is only valid for random access iterators (or more
precisely, ones which provide operator+ which usually means random access)
and is vanishingly rare in my experience. I would have no problem
whatsoever saying that the default definition does the obvious thing, and
if you want to define it differently you just have to write it by hand.