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<title>Issue 521: Garbled requirements for argument_type in reference_wrapper</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#CD1">CD1</a> status.</em></p>
<h3 id="521"><a href="lwg-defects.html#521">521</a>. Garbled requirements for argument_type in reference_wrapper</h3>
<p><b>Section:</b> 22.10.6 <a href="https://wg21.link/refwrap">[refwrap]</a>, 99 [tr.util.refwrp.refwrp] <b>Status:</b> <a href="lwg-active.html#CD1">CD1</a>
 <b>Submitter:</b> Pete Becker <b>Opened:</b> 2005-07-03 <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#refwrap">issues</a> in [refwrap].</p>
<p><b>View all issues with</b> <a href="lwg-status.html#CD1">CD1</a> status.</p>
<p><b>Discussion:</b></p>
<p>
2.1.2/3, second bullet item currently says that reference_wrapper&lt;T&gt; is
derived from unary_function&lt;T, R&gt; if T is:
</p>
<blockquote><p>
a pointer to member function type with cv-qualifier cv and no arguments;
the type T1 is cv T* and R is the return type of the pointer to member function;
</p></blockquote>
<p>
The type of T1 can't be cv T*, 'cause that's a pointer to a pointer to member
function. It should be a pointer to the class that T is a pointer to member of.
Like this:
</p>
<blockquote><p>
a pointer to a member function R T0::f() cv (where cv represents the member
function's cv-qualifiers); the type T1 is cv T0*
</p></blockquote>
<p>
Similarly, bullet item 2 in 2.1.2/4 should be:
</p>
<blockquote><p>
a pointer to a member function R T0::f(T2) cv (where cv represents the member
function's cv-qualifiers); the type T1 is cv T0*
</p></blockquote>


<p id="res-521"><b>Proposed resolution:</b></p>

<p>
Change bullet item 2 in 2.1.2/3:
</p>

<blockquote>
<ul>
<li>
a pointer to member function <del>type with cv-qualifier <code><i>cv</i></code> and no arguments;
the type <code>T1</code> is <code><i>cv</i> T*</code> and <code>R</code> is the return 
type of the pointer to member function</del> <ins><code>R T0::f() <i>cv</i></code>
(where <code><i>cv</i></code> represents the member function's cv-qualifiers);
the type <code>T1</code> is <code><i>cv</i> T0*</code></ins>
</li>
</ul>
</blockquote>

<p>
Change bullet item 2 in 2.1.2/4:
</p>

<blockquote>
<ul>
<li>
a pointer to member function <del>with cv-qualifier <code><i>cv</i></code> and taking one argument
of type <code>T2</code>; the type <code>T1</code> is <code><i>cv</i> T*</code> and 
<code>R</code> is the return type of the pointer to member function</del>
<ins><code>R T0::f(T2) <i>cv</i></code> (where <code><i>cv</i></code> represents the member
function's cv-qualifiers); the type <code>T1</code> is <code><i>cv</i> T0*</code></ins>
</li>
</ul>
</blockquote>






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