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<title>Issue 1380: pair and tuple of references need to better specify move-semantics</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#Resolved">Resolved</a> status.</em></p>
<h3 id="1380"><a href="lwg-defects.html#1380">1380</a>. <code>pair</code> and <code>tuple</code> of references need to better specify move-semantics</h3>
<p><b>Section:</b> 22.3 <a href="https://wg21.link/pairs">[pairs]</a> <b>Status:</b> <a href="lwg-active.html#Resolved">Resolved</a>
 <b>Submitter:</b> DIN <b>Opened:</b> 2010-08-25 <b>Last modified:</b> 2016-01-28</p>
<p><b>Priority: </b>Not Prioritized
</p>
<p><b>View all other</b> <a href="lwg-index.html#pairs">issues</a> in [pairs].</p>
<p><b>View all issues with</b> <a href="lwg-status.html#Resolved">Resolved</a> status.</p>
<p><b>Discussion:</b></p>
<p><b>Addresses DE-16</b></p>
<p>
Several <code>pair</code> and <code>tuple</code> functions in regard to move
operations are incorrectly specified if the member types
are references, because the result of a <code>std::move</code> cannot
be assigned to lvalue-references. In this context the usage
of the requirement sets <code>MoveConstructible</code> and
<code>CopyConstructible</code> also doesn't make sense, because
non-const lvalue-references cannot satisfy these requirements.
</p>

<p><i>[
Resolution proposed by ballot comment
]</i></p>

<p>
Replace the usage of <code>std::move</code> by that of
<code>std::forward</code> and replace <code>MoveConstructible</code> and
<code>CopyConstructible</code> requirements by other requirements.
</p>

<p><i>[
2010-10-24 Daniel adds:
]</i></p>


<blockquote><p>
Accepting <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2010/n3140.html">n3140</a> would solve this issue.
</p></blockquote>

<p><i>[
2010-11 Batavia:
]</i></p>


<blockquote><p>
Resolved by adopting <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2010/n3140.html">n3140</a>.
</p></blockquote>



<p id="res-1380"><b>Proposed resolution:</b></p><p>
See <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2010/n3140.html">n3140</a>.
</p>




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