std::to_address implementation and std::pointer_traits's static_assert

[Jonathan Wakely]

On 20/04/21 21:52 +0200, Ion Gaztañaga wrote:
>On 20/04/2021 15:36, Jonathan Wakely wrote:
>>
>>No, see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96416
>>
>>I consider it a defect in the standard that pointer_traits is not
>>SFINAE friendly, but that's what the current standard requires.
>>
>>I hope it will be changed for C++23.
>
>Hi Jonathan,
>
>Many thanks for your quick and precise reply. And just like Giuseppe 
>D'Angelo described in the bug comments, I also encountered that 
>defining both element_type and value_type (which makes MSVC STL happy, 
>libc++ still not tested) meets LWG3446.
>
>So at least for libstdc++ I will specialize std::pointer_traits for 
>boost::container::vector<>::iterator and will revisit the issue 
>if/when LWG3446 is applied.

It's on the gcc-10 branch as r10-9698, which will be in GCC 10.4:
https://gcc.gnu.org/g:32a859531e854382c18abf0b14a306d83f793eb5
That also includes the recently approved fix for LWG 3541:
https://cplusplus.github.io/LWG/issue3541