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    CWG Issue 2414</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="2414"></A><H4>2414.
  
Unclear results if both member and friend <TT>operator&lt;=&gt;</TT> are declared
</H4>
<B>Section: </B>11.10.1&#160; [<A href="https://wg21.link/class.compare.default">class.compare.default</A>]
 &#160;&#160;&#160;

 <B>Status: </B>C++20
 &#160;&#160;&#160;

 <B>Submitter: </B>Daveed Vandevoorde
 &#160;&#160;&#160;

 <B>Date: </B>2019-05-20<BR>


<P>[Resolved by paper P2002R1, adopted at the February, 2020 meeting.]</P>

<P>According to 11.10.1 [<A href="https://wg21.link/class.compare.default#2">class.compare.default</A>] paragraph 2,</P>

<BLOCKQUOTE>

<P>If the class definition does not explicitly declare
an <TT>==</TT> operator function, but declares a defaulted
three-way comparison operator function, an <TT>==</TT>
operator function is declared implicitly with the same
access as the three-way comparison operator function. The
implicitly-declared <TT>==</TT> operator for a
class <TT>X</TT> is an inline member and is defined as
defaulted in the definition of <TT>X</TT>. If the three-way
comparison operator function is declared as a non-static
const member, the implicitly-declared <TT>==</TT> operator
function is a member of the form</P>

<PRE>
  bool X::operator==(const X&amp;) const;
</PRE>

<P>Otherwise, the implicitly-declared <TT>==</TT> operator
function is of the form</P>

<PRE>
  friend bool operator==(const X&amp;, const X&amp;);
</PRE>

</BLOCKQUOTE>

<P>Paragraph 1 of the section does not preclude declaring
both a member and a friend <TT>operator&lt;=&gt;</TT>, and
it is not clear how the <TT>operator==</TT> should be
declared in that case.</P>

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