[libcxx-commits] [PATCH] D96660: [libcxx] adds concept `std::common_reference_with`

Christopher Di Bella via Phabricator via libcxx-commits libcxx-commits at lists.llvm.org
Tue Feb 16 20:47:39 PST 2021


cjdb added a comment.

In D96660#2566031 <https://reviews.llvm.org/D96660#2566031>, @CaseyCarter wrote:

> In D96660#2564818 <https://reviews.llvm.org/D96660#2564818>, @miscco wrote:
>
>> As far as I can tell the last clause from common_reference is specifically made for something like reference_wrapper types
>
> It's specifically for "Pre-LWG-2993 <https://cplusplus.github.io/LWG/issue2993> `reference_wrapper`"-like types; modern `reference_wrapper` doesn't need it. In fact the only test case I know of for that last clause is to implement pre-LWG-2993 `reference_wrapper` and check `common_reference_t<old_reference_wrapper<meow>, meow&>`.

@CaseyCarter does MSVC test this? I couldn't find it when I looked for an example.


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  https://reviews.llvm.org/D96660/new/

https://reviews.llvm.org/D96660



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