Attempt to make std::pair piecewise constructor noexcept

[François Dumont]

On 12/13/18 11:39 PM, Ville Voutilainen wrote:
> On Fri, 14 Dec 2018 at 00:14, François Dumont <frs.dumont@gmail.com> wrote:
>> Hi
>>
>>       I had a try to make std::pair piecewise constructor noexcept
>> qualified as you'll see in the attached diff. It will help to have more
>> move semantic in associative containers.
>>
>>       But it doesn't work, is_nothrow_constructible<pair<int, int>,
>> piecewise_construct_t, tuple<int>, tuple<int>>::value still false.
>>
>>       Could you let me know before I lose too much time if it is feasible
>> or not ? Or at least if I am on the right path.
>>
>> Thanks for any help,
> std::pair isn't constructible from typename
> _Build_index_tuple<sizeof...(_Args1)>::__type, so it's not
> nothrow_constructible from it either. is_constructible (and
> is_nothrow_constructible) requires public access, and can't detect
> what
> your private constructors do.
>
Thanks a lot, I think I would have lost a lot of time on this one !