https://svn.boost.org/trac10/ticket/3175 <p> I met a compilation error about matching the proper tag_of metafunction. The code snippet is shown as follow. </p> <p> #include &lt;boost/fusion/support.hpp&gt; #include &lt;boost/fusion/container.hpp&gt; #include &lt;boost/fusion/sequence.hpp&gt; #include &lt;boost/fusion/algorithm.hpp&gt; </p> <p> #include &lt;string&gt; #include &lt;iostream&gt; </p> <p> using namespace std; using namespace boost; </p> <p> int _tmain(int argc, _TCHAR* argv[]) { </p> <blockquote> <p> typedef fusion::vector&lt; int, char, string &gt; <a class="missing wiki">VecTuple</a>; <a class="missing wiki">VecTuple</a> stuff( 1, 'a', "Hello, fusion!" ); </p> </blockquote> <blockquote> <p> cout &lt;&lt; stuff &lt;&lt; endl; return 0; </p> </blockquote> <p> } </p> <p> The error message is: 1&gt;e:\libraries\boost_1_37_0\boost\fusion\support\is_sequence.hpp(59) : error C2039: 'tag_of' : is not a member of 'boost::fusion::traits::detail' 1&gt; e:\libraries\boost_1_37_0\boost\utility\enable_if.hpp(36) : see reference to class template instantiation 'boost::fusion::traits::is_sequence&lt;T&gt;' being compiled 1&gt; with 1&gt; [ 1&gt; T=<a class="missing wiki">VecTuple</a> 1&gt; ] 1&gt; e:\samples\boost\fusion\fusion.cpp(52) : see reference to class template instantiation 'boost::enable_if&lt;Cond,T&gt;' being compiled 1&gt; with 1&gt; [ 1&gt; Cond=boost::fusion::traits::is_sequence&lt;<a class="missing wiki">VecTuple</a>&gt;, 1&gt; T=std::ostream &amp; 1&gt; ] </p> <p> I found that if adding the full namespace 'boost::fusion' before '::detail::tag_of' in the file 'is_sequence.hpp', everything will be OK. So I think that maybe is a namespace lookup error in msvc. </p> en-us /htdocs/site/boost.png https://svn.boost.org/trac10/ticket/3175 Trac 1.4.3 Steven Watanabe Sat, 12 Jun 2010 00:49:57 GMT https://svn.boost.org/trac10/ticket/3175#comment:1 https://svn.boost.org/trac10/ticket/3175#comment:1 <ul> <li><strong>status</strong> <span class="trac-field-old">new</span> → <span class="trac-field-new">closed</span> </li> <li><strong>resolution</strong> → <span class="trac-field-new">fixed</span> </li> </ul> <p> This has been fixed. </p> Ticket