modify type_wrapper for the sake of GCC

[SVN r18382]

include/boost/mpl/aux_/type_wrapper.hpp

@@ -1,9 +1,11 @@
-//-----------------------------------------------------------------------------
-// boost mpl/aux/type_wrapper.hpp header file
-// See http://www.boost.org for updates, documentation, and revision history.
-//-----------------------------------------------------------------------------
-//
-// Copyright (c) 2000-02
+
+#ifndef BOOST_MPL_AUX_TYPE_WRAPPER_HPP_INCLUDED
+#define BOOST_MPL_AUX_TYPE_WRAPPER_HPP_INCLUDED
+
+// + file: boost/mpl/aux_/type_wrapper.hpp
+// + last modified: 09/may/03
+
+// Copyright (c) 2000-03
 // Peter Dimov, Aleksey Gurtovoy
 //
 // Permission to use, copy, modify, distribute and sell this software
@@ -13,9 +15,10 @@
 // supporting documentation. No representations are made about the 
 // suitability of this software for any purpose. It is provided "as is" 
 // without express or implied warranty.
+//
+// See http://www.boost.org/libs/mpl for documentation.
 
-#ifndef BOOST_MPL_AUX_TYPE_WRAPPER_HPP_INCLUDED
-#define BOOST_MPL_AUX_TYPE_WRAPPER_HPP_INCLUDED
+#include "boost/mpl/aux_/config/ctps.hpp"
 
 namespace boost {
 namespace mpl {
@@ -26,6 +29,24 @@ template< typename T > struct type_wrapper
     typedef T type;
 };
 
+#if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
+// agurt 08/may/03: a complicated way to extract the wrapped type; need it 
+// mostly for the sake of GCC (3.2.x), which ICEs if you try to extract the 
+// nested 'type' from 'type_wrapper<T>' when the latter was the result of a
+// 'typeof' expression
+template< typename T > struct wrapped_type;
+
+template< typename T > struct wrapped_type< type_wrapper<T> >
+{
+    typedef T type;
+};
+#else
+template< typename W > struct wrapped_type
+{
+    typedef typename W::type type;
+};
+#endif
+
 } // namespace aux
 } // namespace mpl
 } // namespace boost