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<title>Issue 1049: Move assignment of promise inverted</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="1049"><a href="lwg-defects.html#1049">1049</a>. Move assignment of <code>promise</code> inverted</h3>
<p><b>Section:</b> 32.10.6 <a href="https://wg21.link/futures.promise">[futures.promise]</a> <b>Status:</b> <a href="lwg-active.html#Resolved">Resolved</a>
 <b>Submitter:</b> Alisdair Meredith <b>Opened:</b> 2009-03-12 <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#futures.promise">issues</a> in [futures.promise].</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 UK 339 [CD1]</b></p>

<p>
Move assignment is going in the wrong direction, assigning from
<code>*this</code> to the passed rvalue, and then returning a reference to
an unusable <code>*this</code>.
</p>

<p><i>[
Summit:
]</i></p>


<blockquote>
<p>
Agree, move to Review.
</p>
</blockquote>

<p><i>[
Batavia (2009-05):
]</i></p>

<blockquote><p>
We recommend deferring this issue until after Detlef's paper (on futures)
has been issued.
</p></blockquote>

<p><i>[
2009-10 Santa Cruz:
]</i></p>


<blockquote><p>
<del>NAD Editorial</del><ins>Resolved</ins>.  Addressed by
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2997.htm">N2997</a>.
</p></blockquote>



<p id="res-1049"><b>Proposed resolution:</b></p>
<p>
Strike 32.10.6 <a href="https://wg21.link/futures.promise">[futures.promise]</a> p6 and change p7:
</p>

<blockquote><pre>
promise&amp; operator=(promise&amp;&amp; rhs);
</pre>
<blockquote>
<p>
<del>-6- <i>Effects:</i> move assigns its associated state to <code>rhs</code>.</del>
</p>
<p>
-7- <i>Postcondition:</i> <del><code>*this</code> has no associated
state.</del> <ins>associated state of <code>*this</code> is the same as the
associated state of <code>rhs</code> before the call. <code>rhs</code> has no
associated state.</ins>
</p>
</blockquote>
</blockquote>






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