--- bool_trait_def.hpp  2 Sep 2004 15:41:27 -0000       1.16
+++ bool_trait_def.hpp  4 Oct 2004 16:04:09 -0000
@@ -20,6 +20,8 @@
 #   define BOOST_TT_AUX_BOOL_TRAIT_VALUE_DECL(C) \
     typedef BOOST_MPL_AUX_ADL_BARRIER_NAMESPACE::bool_< C > type; \
     enum { value = type::value }; \
+    operator BOOST_MPL_AUX_ADL_BARRIER_NAMESPACE::bool_< C >() const \
+        { return BOOST_MPL_AUX_ADL_BARRIER_NAMESPACE::bool_< C >(); } \
     /**/
 #   define BOOST_TT_AUX_BOOL_C_BASE(C)