One thing intrigues me, why use `univeral tempalte` and not use `using` keyword?
As using was not allowed in this context,
having overlapping meaning, it is shorten.
Overall it would fit nicely in this spot.

wt., 26 mar 2024 o 14:29 Gašper Ažman via Std-Proposals
<std-proposals_at_[hidden]> napisał(a):
>
> That's correct. We are hoping to catch c++26.
>
> On Tue, Mar 26, 2024, 22:15 Jonathan Wakely via Std-Proposals <std-proposals_at_[hidden]> wrote:
>>
>>
>>
>> On Tue, 26 Mar 2024 at 12:40, Frederick Virchanza Gotham via Std-Proposals <std-proposals_at_[hidden]> wrote:
>>>
>>> Looking at P2098r1:
>>>
>>> https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2020/p2098r1.pdf
>>>
>>> The given implementation works fine for specialisations of 'vector', but not for specialisations of 'array', as follows:
>>>
>>> #include <cstddef>
>>> #include <array>
>>> #include <type_traits>
>>> #include <vector>
>>>
>>> namespace std {
>>> template< class T , template<class...> class Primary >
>>> struct is_specialization_of : false_type {};
>>> template< template<class...> class Primary , class... Args >
>>> struct is_specialization_of< Primary<Args...>, Primary> : true_type {};
>>> }
>>>
>>> int main(void)
>>> {
>>> using std::is_specialization_of;
>>> static_assert( is_specialization_of< std::vector<int>, std::vector >::value );
>>> static_assert( is_specialization_of< std::array<int, 5>, std::array >::value );
>>> }
>>>
>>> Compiler output:
>>>
>>> a.cpp: In function 'int main()':
>>> a.cpp:22:73: error: type/value mismatch at argument 2 in template parameter list for 'template<class T, template<class ...> class Primary> struct std::is_specialization_of'
>>> a.cpp:22:73: note: expected a template of type 'template<class ...> class Primary', got 'template<class _Tp, long unsigned int _Nm> struct std::array'
>>>
>>> If 'is_specialization_of' is to be written into the Standard, shall it be worded that it requires compiler support to let it work with every template class (and not just the ones whose parameters are exclusively all types)? Or will the use of this feature be restricted to template classes whose parameters are all types?
>>>
>>> I'm talking something like:
>>>
>>> namespace std {
>>> template< class T , /* COMPILER_SUPPORT */ Primary >
>>> struct is_specialization_of : false_type {};
>>> template< /* COMPILER_SUPPORT */ Primary , class... Args >
>>> struct is_specialization_of< Primary<Args...>, Primary> : true_type {};
>>> }
>>
>>
>>
>> I think https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2024/p2989r1.pdf is the latesty work in this space.
>>
>>
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