Index: boost/mpl/aux_/push_back_impl.hpp
===================================================================
--- boost/mpl/aux_/push_back_impl.hpp	(revision 54788)
+++ boost/mpl/aux_/push_back_impl.hpp	(working copy)
@@ -25,8 +25,7 @@
 
 namespace boost { namespace mpl {
 
-template< typename Tag >
-struct has_push_back_impl;
+struct has_push_back_arg;
 
 // agurt 05/feb/04: no default implementation; the stub definition is needed 
 // to enable the default 'has_push_back' implementation below
@@ -39,7 +38,7 @@
         // if you've got an assert here, you are requesting a 'push_back' 
         // specialization that doesn't exist.
         BOOST_MPL_ASSERT_MSG(
-              ( boost::is_same< T, has_push_back_impl<T> >::value )
+              ( boost::is_same< T, has_push_back_arg >::value )
             , REQUESTED_PUSH_BACK_SPECIALIZATION_FOR_SEQUENCE_DOES_NOT_EXIST
             , ( Sequence )
             );
@@ -51,13 +50,13 @@
 {
     template< typename Seq > struct apply
 #if !defined(BOOST_MPL_CFG_NO_NESTED_FORWARDING)
-        : aux::has_type< push_back< Seq, has_push_back_impl<Tag> > >
+        : aux::has_type< push_back< Seq, has_push_back_arg > >
     {
 #else
     {
-        typedef aux::has_type< push_back< Seq, has_push_back_impl<Tag> > > type;
+        typedef aux::has_type< push_back< Seq, has_push_back_arg > > type;
         BOOST_STATIC_CONSTANT(bool, value = 
-              (aux::has_type< push_back< Seq, has_push_back_impl<Tag> > >::value)
+              (aux::has_type< push_back< Seq, has_push_back_arg > >::value)
             );
 #endif
     };