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<title>Issue 4011: "Effects: Equivalent to return" in [span.elem]</title>
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<p><em>This page is a snapshot from the LWG issues list, see the <a href="lwg-active.html">Library Active Issues List</a> for more information and the meaning of <a href="lwg-active.html#WP">WP</a> status.</em></p>
<h3 id="4011"><a href="lwg-defects.html#4011">4011</a>. "<i>Effects</i>: Equivalent to return" in [span.elem]</h3>
<p><b>Section:</b> 23.7.2.2.6 <a href="https://wg21.link/span.elem">[span.elem]</a> <b>Status:</b> <a href="lwg-active.html#WP">WP</a>
 <b>Submitter:</b> Arthur O'Dwyer <b>Opened:</b> 2023-11-09 <b>Last modified:</b> 2024-04-02</p>
<p><b>Priority: </b>Not Prioritized
</p>
<p><b>View all issues with</b> <a href="lwg-status.html#WP">WP</a> status.</p>
<p><b>Discussion:</b></p>
<p>
In reviewing the wording for <a href="https://wg21.link/P2821" title=" span.at()">P2821</a> <code>span.at()</code>, it had been noticed that 
23.7.2.2.6 <a href="https://wg21.link/span.elem">[span.elem]</a> uses a lot of "<i>Effects</i>: Equivalent to return [&hellip;];" which 
could be simply "<i>Returns</i>:  [&hellip;]".
<p/>
For comparison, 27.3.3.6 <a href="https://wg21.link/string.view.access">[string.view.access]</a> uses "<i>Returns</i>: ..." instead, so I 
suggest that 23.7.2.2.6 <a href="https://wg21.link/span.elem">[span.elem]</a> should be consistent with that.
</p>

<p><i>[2024-03-11; Reflector poll]</i></p>

<p>
Set status to Tentatively Ready after seven votes in favour during reflector poll.
</p>

<p><i>[Tokyo 2024-03-23; Status changed: Voting &rarr; WP.]</i></p>



<p id="res-4011"><b>Proposed resolution:</b></p>
<p>
This wording is relative to <a href="https://wg21.link/N4964" title=" Working Draft, Programming Languages — C++">N4964</a>.
</p>

<ol>

<li><p>Modify 23.7.2.2.6 <a href="https://wg21.link/span.elem">[span.elem]</a> as indicated:</p>

<pre>
constexpr reference operator[](size_type idx) const;
</pre>
<blockquote>
<p>
-1- <i>Preconditions</i>: <code>idx &lt; size()</code> is <code>true</code>.
<p/>
-2- <i><del>Effects</del><ins>Returns</ins></i>: <del>Equivalent to:</del> <code><del>return</del> *(data() + idx)<del>;</del></code><ins>.</ins>
<p/>
<ins>-?- <i>Throws</i>: Nothing.</ins>
</p>
</blockquote>
<pre>
constexpr reference front() const;
</pre>
<blockquote>
<p>
-3- <i>Preconditions</i>: <code>empty()</code> is <code>false</code>.
<p/>
-4- <i><del>Effects</del><ins>Returns</ins></i>: <del>Equivalent to:</del> <code><del>return</del> *data()<del>;</del></code><ins>.</ins>
<p/>
<ins>-?- <i>Throws</i>: Nothing.</ins>
</p>
</blockquote>
<pre>
constexpr reference back() const;
</pre>
<blockquote>
<p>
-5- <i>Preconditions</i>: <code>empty()</code> is <code>false</code>.
<p/>
-6- <i><del>Effects</del><ins>Returns</ins></i>: <del>Equivalent to:</del> <code><del>return</del> *(data() + (size() - 1))<del>;</del></code><ins>.</ins>
<p/>
<ins>-?- <i>Throws</i>: Nothing.</ins>
</p>
</blockquote>
<pre>
constexpr pointer data() const noexcept;
</pre>
<blockquote>
<p>
-7- <i><del>Effects</del><ins>Returns</ins></i>: <del>Equivalent to:</del> <code><del>return</del> <i>data_</i><del>;</del></code><ins>.</ins>
</p>
</blockquote>

</li>

</ol>





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