[NFC][libc++] Addresses LWG3935.

[Mordante]

Summary

Note libc++ implemented this in its initial version.

Implements

• LWG3935 template<class X> constexpr complex& operator=(const complex<X>&) has no specification

[ldionne]

Do we have a test for this? LGTM if we do, otherwise let's add one.

[Mordante]

In D153287#4433463, @ldionne wrote:

Do we have a test for this? LGTM if we do, otherwise let's add one.

Yes in libcxx/test/std/numerics/complex.number/complex.member.ops/assignment_complex.pass.cpp

libcxx/docs/Status/Cxx2cIssues.csv

 "Issue #","Issue Name","Meeting","Status","First released version","Labels"
 "`2994 <https://wg21.link/LWG2994>`__","Needless UB for ``basic_string`` and ``basic_string_view``","Varna June 2023","","",""
 "`3884 <https://wg21.link/LWG3884>`__","``flat_foo`` is missing allocator-extended copy/move constructors","Varna June 2023","","","|flat_containers|"
 "`3885 <https://wg21.link/LWG3885>`__","``op`` should be in [zombie.names]","Varna June 2023","","",""
 "`3887 <https://wg21.link/LWG3887>`__","Version macro for ``allocate_at_least``","Varna June 2023","","",""
 "`3893 <https://wg21.link/LWG3893>`__","LWG 3661 broke ``atomic<shared_ptr<T>> a; a = nullptr;``","Varna June 2023","","",""
 "`3894 <https://wg21.link/LWG3894>`__","``generator::promise_type::yield_value(ranges::elements_of<Rng, Alloc>)`` should not be ``noexcept``","Varna June 2023","","",""
 "`3903 <https://wg21.link/LWG3903>`__","span destructor is redundantly noexcept","Varna June 2023","","",""
 "`3904 <https://wg21.link/LWG3904>`__","``lazy_split_view::outer-iterator``'s const-converting constructor isn't setting ``trailing_empty_``","Varna June 2023","","","|ranges|"
 "`3905 <https://wg21.link/LWG3905>`__","Type of ``std::fexcept_t``","Varna June 2023","","",""
 "`3912 <https://wg21.link/LWG3912>`__","``enumerate_view::iterator::operator-`` should be ``noexcept``","Varna June 2023","","","|ranges|"
 "`3914 <https://wg21.link/LWG3914>`__","Inconsistent template-head of ``ranges::enumerate_view``","Varna June 2023","","","|ranges|"
 "`3915 <https://wg21.link/LWG3915>`__","Redundant paragraph about expression variations","Varna June 2023","","","|ranges|"
 "`3925 <https://wg21.link/LWG3925>`__","Concept ``formattable``'s definition is incorrect","Varna June 2023","|In Progress|","","|format|"
 "`3927 <https://wg21.link/LWG3927>`__","Unclear preconditions for ``operator[]`` for sequence containers","Varna June 2023","","",""
-"`3935 <https://wg21.link/LWG3935>`__","``template<class X> constexpr complex& operator=(const complex<X>&)`` has no specification","Varna June 2023","","",""
+"`3935 <https://wg21.link/LWG3935>`__","``template<class X> constexpr complex& operator=(const complex<X>&)`` has no specification","Varna June 2023","|Complete|","Clang 3.4",""
 "`3938 <https://wg21.link/LWG3938>`__","Cannot use ``std::expected`` monadic ops with move-only ``error_type``","Varna June 2023","","",""
 "`3940 <https://wg21.link/LWG3940>`__","``std::expected<void, E>::value()`` also needs ``E`` to be copy constructible","Varna June 2023","","",""
 "","","","","",""
 "`3343 <https://wg21.link/LWG3343>`__","Ordering of calls to ``unlock()`` and ``notify_all()`` in Effects element of ``notify_all_at_thread_exit()`` should be reversed","Not Yet Adopted","|Complete|","16.0",""
 "`3892 <https://wg21.link/LWG3892>`__","Incorrect formatting of nested ranges and tuples","Not Yet Adopted","|Complete|","17.0","|format|"
 "","","","","",""