Update status

[zoecarver]

Summary

• 2750 nothing to do because std::experimental::optional no longer exists.
• 2969 commited.
• 2696 because it has already been implemented and tests exist.
• 2451 nothing to do because std::experimental::optional no longer exists.

[zoecarver]

• updated wrong issue (oops)

[ldionne]

2750 nothing to do because std::experimental::optional no longer exists.

This is correct, however the current wording for optional::optional(U&&) does NOT have a condition like !std::is_same<T, std::remove_reference_t<U>>::value. Was it "forgotten" when we Standardized std::optional? If so, then maybe we need to create a LWG issue.

[zoecarver]

• mark another issue complete

[zoecarver]

@ldionne I talked with @mclow.lists about this because I was wondering the same thing. He is looking into it.

It seems like an odd constraint to have because there is no other constructor which would allow for constructing an optional<T> with a T.

[mclow.lists]

In D62932#1531634, @ldionne wrote:

2750 nothing to do because std::experimental::optional no longer exists.

This is correct, however the current wording for optional::optional(U&&) does NOT have a condition like !std::is_same<T, std::remove_reference_t<U>>::value. Was it "forgotten" when we Standardized std::optional? If so, then maybe we need to create a LWG issue.

I'm looking into that; that portion of the standard has seen a lot of churn.

[mclow.lists]

Committed as revision 362659

www/cxx1z_status.html

<!--   <I>Note: "NAD" means that the issue was deemed "Not a defect"</I> -->
   <tr><td><a href="https://wg21.link/LWG2310">2310</a></td><td>Public exposition only member in std::array</td><td>Oulu</td><td>Complete</td></tr>
   <tr><td><a href="https://wg21.link/LWG2312">2312</a></td><td>tuple's constructor constraints need to be phrased more precisely</td><td>Oulu</td><td>Complete</td></tr>
   <tr><td><a href="https://wg21.link/LWG2328">2328</a></td><td>Rvalue stream extraction should use perfect forwarding</td><td>Oulu</td><td>Complete</td></tr>
   <tr><td><a href="https://wg21.link/LWG2393">2393</a></td><td>std::function's Callable definition is broken</td><td>Oulu</td><td>Complete</td></tr>
   <tr><td><a href="https://wg21.link/LWG2422">2422</a></td><td>std::numeric_limits&lt;T&gt;::is_modulo description: "most machines" errata</td><td>Oulu</td><td>Complete</td></tr>
   <tr><td><a href="https://wg21.link/LWG2426">2426</a></td><td>Issue about compare_exchange</td><td>Oulu</td><td></td></tr>
   <tr><td><a href="https://wg21.link/LWG2436">2436</a></td><td>Comparators for associative containers should always be CopyConstructible</td><td>Oulu</td><td>Complete</td></tr>
   <tr><td><a href="https://wg21.link/LWG2441">2441</a></td><td>Exact-width atomic typedefs should be provided</td><td>Oulu</td><td>Complete</td></tr>
-  <tr><td><a href="https://wg21.link/LWG2451">2451</a></td><td>[fund.ts.v2] optional should 'forward' T's implicit conversions</td><td>Oulu</td><td></td></tr>
+  <tr><td><a href="https://wg21.link/LWG2451">2451</a></td><td>[fund.ts.v2] optional should 'forward' T's implicit conversions</td><td>Oulu</td><td>Nothing to do</td></tr>
   <tr><td><a href="https://wg21.link/LWG2509">2509</a></td><td>[fund.ts.v2] any_cast doesn't work with rvalue reference targets and cannot move with a value target</td><td>Oulu</td><td>Complete</td></tr>
   <tr><td><a href="https://wg21.link/LWG2516">2516</a></td><td>[fund.ts.v2] Public "exposition only" members in observer_ptr</td><td>Oulu</td><td></td></tr>
   <tr><td><a href="https://wg21.link/LWG2542">2542</a></td><td>Missing const requirements for associative containers</td><td>Oulu</td><td></td></tr>
   <tr><td><a href="https://wg21.link/LWG2549">2549</a></td><td>Tuple EXPLICIT constructor templates that take tuple parameters end up taking references to temporaries and will create dangling references</td><td>Oulu</td><td>Complete</td></tr>
   <tr><td><a href="https://wg21.link/LWG2550">2550</a></td><td>Wording of unordered container's clear() method complexity</td><td>Oulu</td><td>Complete</td></tr>
   <tr><td><a href="https://wg21.link/LWG2551">2551</a></td><td>[fund.ts.v2] "Exception safety" cleanup in library fundamentals required</td><td>Oulu</td><td>Complete</td></tr>
   <tr><td><a href="https://wg21.link/LWG2555">2555</a></td><td>[fund.ts.v2] No handling for over-aligned types in optional</td><td>Oulu</td><td>Complete</td></tr>
   <tr><td><a href="https://wg21.link/LWG2573">2573</a></td><td>[fund.ts.v2] std::hash&lt;std::experimental::shared_ptr&gt; does not work for arrays</td><td>Oulu</td><td></td></tr>
<!--   <I>Note: "NAD" means that the issue was deemed "Not a defect"</I> -->
   <tr><td><a href="https://wg21.link/LWG2672">2672</a></td><td>Should is_empty use error_code in its specification?</td><td>Issaquah</td><td>Complete</td></tr>
   <tr><td><a href="https://wg21.link/LWG2678">2678</a></td><td>std::filesystem enum classes overspecified</td><td>Issaquah</td><td>Complete</td></tr>
   <tr><td><a href="https://wg21.link/LWG2679">2679</a></td><td>Inconsistent Use of Effects and Equivalent To</td><td>Issaquah</td><td>Complete</td></tr>
   <tr><td><a href="https://wg21.link/LWG2680">2680</a></td><td>Add "Equivalent to" to filesystem</td><td>Issaquah</td><td>Complete</td></tr>
   <tr><td><a href="https://wg21.link/LWG2681">2681</a></td><td>filesystem::copy() cannot copy symlinks</td><td>Issaquah</td><td>Complete</td></tr>
   <tr><td><a href="https://wg21.link/LWG2682">2682</a></td><td>filesystem::copy() won't create a symlink to a directory</td><td>Issaquah</td><td>Complete</td></tr>
   <tr><td><a href="https://wg21.link/LWG2686">2686</a></td><td>Why is std::hash specialized for error_code, but not error_condition?</td><td>Issaquah</td><td>Complete</td></tr>
   <tr><td><a href="https://wg21.link/LWG2694">2694</a></td><td>Application of LWG 436 accidentally deleted definition of "facet"</td><td>Issaquah</td><td>Complete</td></tr>
-  <tr><td><a href="https://wg21.link/LWG2696">2696</a></td><td>Interaction between make_shared and enable_shared_from_this is underspecified</td><td>Issaquah</td><td></td></tr>
+  <tr><td><a href="https://wg21.link/LWG2696">2696</a></td><td>Interaction between make_shared and enable_shared_from_this is underspecified</td><td>Issaquah</td><td>Nothing to do</td></tr>
   <tr><td><a href="https://wg21.link/LWG2699">2699</a></td><td>Missing restriction in [numeric.requirements]</td><td>Issaquah</td><td>Complete</td></tr>
   <tr><td><a href="https://wg21.link/LWG2712">2712</a></td><td>copy_file(from, to, ...) has a number of unspecified error conditions</td><td>Issaquah</td><td>Complete</td></tr>
   <tr><td><a href="https://wg21.link/LWG2722">2722</a></td><td>equivalent incorrectly specifies throws clause</td><td>Issaquah</td><td>Complete</td></tr>
   <tr><td><a href="https://wg21.link/LWG2729">2729</a></td><td>Missing SFINAE on std::pair::operator=</td><td>Issaquah</td><td></td></tr>
   <tr><td><a href="https://wg21.link/LWG2732">2732</a></td><td>Questionable specification of path::operator/= and path::append</td><td>Issaquah</td><td>Complete</td></tr>
   <tr><td><a href="https://wg21.link/LWG2733">2733</a></td><td>[fund.ts.v2] gcd / lcm and bool</td><td>Issaquah</td><td>Complete</td></tr>
   <tr><td><a href="https://wg21.link/LWG2735">2735</a></td><td>std::abs(short), std::abs(signed char) and others should return int instead of double in order to be compatible with C++98 and C</td><td>Issaquah</td><td></td></tr>
   <tr><td><a href="https://wg21.link/LWG2736">2736</a></td><td>nullopt_t insufficiently constrained</td><td>Issaquah</td><td>Complete</td></tr>
   <tr><td><a href="https://wg21.link/LWG2738">2738</a></td><td>is_constructible with void types</td><td>Issaquah</td><td>Complete</td></tr>
   <tr><td><a href="https://wg21.link/LWG2739">2739</a></td><td>Issue with time_point non-member subtraction with an unsigned duration</td><td>Issaquah</td><td>Complete</td></tr>
   <tr><td><a href="https://wg21.link/LWG2740">2740</a></td><td>constexpr optional<T>::operator-></td><td>Issaquah</td><td>Complete</td></tr>
   <tr><td><a href="https://wg21.link/LWG2742">2742</a></td><td>Inconsistent string interface taking string_view</td><td>Issaquah</td><td>Complete</td></tr>
   <tr><td><a href="https://wg21.link/LWG2744">2744</a></td><td>any's in_place constructors</td><td>Issaquah</td><td>Complete</td></tr>
   <tr><td><a href="https://wg21.link/LWG2745">2745</a></td><td>[fund.ts.v2] Implementability of LWG 2451</td><td>Issaquah</td><td>Complete</td></tr>
   <tr><td><a href="https://wg21.link/LWG2747">2747</a></td><td>Possibly redundant std::move in [alg.foreach]</td><td>Issaquah</td><td>Complete</td></tr>
   <tr><td><a href="https://wg21.link/LWG2748">2748</a></td><td>swappable traits for optionals</td><td>Issaquah</td><td>Complete</td></tr>
   <tr><td><a href="https://wg21.link/LWG2749">2749</a></td><td>swappable traits for variants</td><td>Issaquah</td><td>Complete</td></tr>
-  <tr><td><a href="https://wg21.link/LWG2750">2750</a></td><td>[fund.ts.v2] LWG 2451 conversion constructor constraint</td><td>Issaquah</td><td></td></tr>
+  <tr><td><a href="https://wg21.link/LWG2750">2750</a></td><td>[fund.ts.v2] LWG 2451 conversion constructor constraint</td><td>Issaquah</td><td>Nothing to do</td></tr>
   <tr><td><a href="https://wg21.link/LWG2752">2752</a></td><td>"Throws:" clauses of async and packaged_task are unimplementable</td><td>Issaquah</td><td></td></tr>
   <tr><td><a href="https://wg21.link/LWG2755">2755</a></td><td>[string.view.io] uses non-existent basic_string_view::to_string function</td><td>Issaquah</td><td>Complete</td></tr>
   <tr><td><a href="https://wg21.link/LWG2756">2756</a></td><td>C++ WP optional<T> should 'forward' T's implicit conversions</td><td>Issaquah</td><td>Complete</td></tr>
   <tr><td><a href="https://wg21.link/LWG2758">2758</a></td><td>std::string{}.assign("ABCDE", 0, 1) is ambiguous</td><td>Issaquah</td><td>Complete</td></tr>
   <tr><td><a href="https://wg21.link/LWG2759">2759</a></td><td>gcd / lcm and bool for the WP</td><td>Issaquah</td><td>Complete</td></tr>
   <tr><td><a href="https://wg21.link/LWG2760">2760</a></td><td>non-const basic_string::data should not invalidate iterators</td><td>Issaquah</td><td>Complete</td></tr>
   <tr><td><a href="https://wg21.link/LWG2765">2765</a></td><td>Did LWG 1123 go too far?</td><td>Issaquah</td><td>Complete</td></tr>
   <tr><td><a href="https://wg21.link/LWG2767">2767</a></td><td>not_fn call_wrapper can form invalid types</td><td>Issaquah</td><td>Complete</td></tr>

www/cxx2a_status.html

-->
    <tr><td></td><td></td><td></td><td></td></tr>
   <tr><td><a href="https://wg21.link/LWG2164">2164</a></td><td>What are the semantics of <tt>vector.emplace(vector.begin(), vector.back())</tt>?</td><td>Jacksonville</td><td>Complete</td></tr>
   <tr><td><a href="https://wg21.link/LWG2243">2243</a></td><td><tt>istream::putback</tt> problem</td><td>Jacksonville</td><td>Complete</td></tr>
   <tr><td><a href="https://wg21.link/LWG2816">2816</a></td><td><tt>resize_file</tt> has impossible postcondition</td><td>Jacksonville</td><td><i>Nothing to do</i></td></tr>
   <tr><td><a href="https://wg21.link/LWG2843">2843</a></td><td>Unclear behavior of <tt>std::pmr::memory_resource::do_allocate()</tt></td><td>Jacksonville</td><td>Complete</td></tr>
   <tr><td><a href="https://wg21.link/LWG2849">2849</a></td><td>Why does <tt>!is_regular_file(from)</tt> cause <tt>copy_file</tt> to report a "file already exists" error?</td><td>Jacksonville</td><td><i>Nothing to do</i></td></tr>
   <tr><td><a href="https://wg21.link/LWG2851">2851</a></td><td><tt>std::filesystem</tt> enum classes are now underspecified</td><td>Jacksonville</td><td><i>Nothing to do</i></td></tr>
   <tr><td><a href="https://wg21.link/LWG2946">2946</a></td><td>LWG 2758's resolution missed further corrections</td><td>Jacksonville</td><td>Complete</td></tr>
-  <tr><td><a href="https://wg21.link/LWG2969">2969</a></td><td><tt>polymorphic_allocator::construct()</tt> shouldn't pass <tt>resource()</tt></td><td>Jacksonville</td><td></td></tr>
+  <tr><td><a href="https://wg21.link/LWG2969">2969</a></td><td><tt>polymorphic_allocator::construct()</tt> shouldn't pass <tt>resource()</tt></td><td>Jacksonville</td><td>Complete</td></tr>
   <tr><td><a href="https://wg21.link/LWG2975">2975</a></td><td>Missing case for <tt>pair</tt> construction in scoped and polymorphic allocators</td><td>Jacksonville</td><td></td></tr>
   <tr><td><a href="https://wg21.link/LWG2989">2989</a></td><td><tt>path</tt>'s stream insertion operator lets you insert everything under the sun</td><td>Jacksonville</td><td>Completed</td></tr>
   <tr><td><a href="https://wg21.link/LWG3000">3000</a></td><td><tt>monotonic_memory_resource::do_is_equal</tt> uses <tt>dynamic_cast</tt> unnecessarily</td><td>Jacksonville</td><td></td></tr>
   <tr><td><a href="https://wg21.link/LWG3002">3002</a></td><td>[networking.ts] <tt>basic_socket_acceptor::is_open()</tt> isn't <tt>noexcept</tt></td><td>Jacksonville</td><td></td></tr>
   <tr><td><a href="https://wg21.link/LWG3004">3004</a></td><td>&sect;[string.capacity] and &sect;[vector.capacity] should specify time complexity for <tt>capacity()</tt></td><td>Jacksonville</td><td><i>Nothing to do</i></td></tr>
   <tr><td><a href="https://wg21.link/LWG3005">3005</a></td><td>Destruction order of arrays by <tt>make_shared/allocate_shared</tt> only recommended?</td><td>Jacksonville</td><td></td></tr>
   <tr><td><a href="https://wg21.link/LWG3007">3007</a></td><td><tt>allocate_shared</tt> should rebind allocator to <i>cv</i>-unqualified <tt>value_type</tt> for construction</td><td>Jacksonville</td><td></td></tr>
   <tr><td><a href="https://wg21.link/LWG3009">3009</a></td><td>Including <tt>&lt;string_view&gt;</tt> doesn't provide <tt>std::size/empty/data</tt></td><td>Jacksonville</td><td>Complete</td></tr>