Boost C++ Libraries: Ticket #7975: mpl::insert<...>::type::type returns empty map when inserting into an mpl::map https://svn.boost.org/trac10/ticket/7975 <p> The following code: </p> <pre class="wiki">using namespace boost::mpl; insert&lt;map&lt;&gt;, pair&lt;int_&lt;1&gt;, int_&lt;2&gt; &gt; &gt;::type::type </pre><p> gives </p> <pre class="wiki">boost::mpl::map0&lt;&gt; </pre> en-us Boost C++ Libraries /htdocs/site/boost.png https://svn.boost.org/trac10/ticket/7975 Trac 1.4.3