[v3] plus<void>

[Jonathan Wakely]

On 25 September 2013 11:15, Marc Glisse wrote:
>
> I think that's one of those magical properties that people associate with
> future features that are still rather vague, modules and concepts being 2 of
> the worst. If we end up having to add a line:
> requires(well_formed(std::forward<_Tp>(__x) + std::forward<_Up>(__y)))
> we won't have made the code smaller.

While I agree with the sentiment, shurely that would be
requires(Addable<_Tp, _Up>())