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<title>Issue 2866: Incorrect derived classes constraints</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#C++17">C++17</a> status.</em></p>
<h3 id="2866"><a href="lwg-defects.html#2866">2866</a>. Incorrect derived classes constraints</h3>
<p><b>Section:</b> 16.4.6.13 <a href="https://wg21.link/derivation">[derivation]</a> <b>Status:</b> <a href="lwg-active.html#C++17">C++17</a>
 <b>Submitter:</b> Great Britain <b>Opened:</b> 2017-02-03 <b>Last modified:</b> 2020-09-06</p>
<p><b>Priority: </b>Not Prioritized
</p>
<p><b>View all other</b> <a href="lwg-index.html#derivation">issues</a> in [derivation].</p>
<p><b>View all issues with</b> <a href="lwg-status.html#C++17">C++17</a> status.</p>
<p><b>Discussion:</b></p>
<p><b>Addresses GB 36</b></p>

<p>For bullet (3.2), no base classes are described as non-virtual. Rather, base 
classes are not specified as virtual, a subtly different negative.</p>

<p>
Proposed change:
</p>
<p>
Rewrite bullet 3.2:
</p>
<blockquote>
<p>
Every base class not specified as virtual shall not be virtual;
</p>
</blockquote>

<p><i>[Kona 2017-03-01]</i></p>

<p>Accepted as Immediate to resolve NB comment.</p>


<p id="res-2866"><b>Proposed resolution:</b></p>
<p>This wording is relative to <a href="https://wg21.link/n4640">N4640</a>.</p>
<ol>

<li><p>Modify 16.4.6.13 <a href="https://wg21.link/derivation">[derivation]</a> paragraph 3.2 as indicated:</p>
<blockquote>
<del>Every base class described as non-<code>virtual</code> shall not be virtual;</del>
<ins>Every base class not specified as <code>virtual</code> shall not be virtual;</ins>
</blockquote>
</li>
</ol>






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