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    CWG Issue 1114</TITLE>
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<P><EM>This is an unofficial snapshot of the ISO/IEC JTC1 SC22 WG21
  Core Issues List revision 118b.
  See http://www.open-std.org/jtc1/sc22/wg21/ for the official
  list.</EM></P>
<P>2025-09-28</P>
<HR>
<A NAME="1114"></A><H4>1114.
  
Incorrect use of placement <TT>new</TT> in example
</H4>
<B>Section: </B>6.8.4&#160; [<A href="https://wg21.link/basic.life">basic.life</A>]
 &#160;&#160;&#160;

 <B>Status: </B>C++11
 &#160;&#160;&#160;

 <B>Submitter: </B>GB
 &#160;&#160;&#160;

 <B>Date: </B>2010-08-02<BR><BR>


<P>[Voted into the WP at the November, 2010 meeting.]</P>

<A href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2011/n3296.html#GB18">N3092 comment
  GB&#160;18<BR></A>

<P>The example in 6.8.4 [<A href="https://wg21.link/basic.life#9">basic.life</A>] paragraph 9 reads,</P>

<PRE>
    struct B {
      B();
      ~B();
    };

    const B b;

    void h() {
      b.~B();
      new (&amp;b) const B;  //<SPAN CLASS="cmnt"> undefined behavior</SPAN>
    }
</PRE>

<P>Assuming that the placement <TT>new</TT> is intended to use
the operator defined in the Standard library, the <I>new-expression</I>
is ill-formed, because there is no implicit conversion from
&#8220;pointer to const <TT>B</TT>&#8221; to <TT>void*</TT>.</P>

<P><B>Proposed resolution (August, 2010):</B></P>

<P>Change the example in 6.8.4 [<A href="https://wg21.link/basic.life#9">basic.life</A>] paragraph 9 as
follows:</P>

<PRE>
    ...
    new (<INS>const_cast&lt;B *&gt;(</INS>&amp;b<INS>)</INS>) const B;  //<SPAN CLASS="cmnt"> undefined behavior</SPAN>
    ...
</PRE>

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