--- optional.hpp	2007-03-07 23:17:23.000000000 +0300
+++ optional_fixed.hpp	2009-09-03 11:00:17.642364500 +0400
@@ -28,6 +28,7 @@
 #include "boost/detail/reference_content.hpp"
 #include "boost/none.hpp"
 #include "boost/utility/compare_pointees.hpp"
+#include "boost/utility/addressof.hpp"
 
 #include "boost/optional/optional_fwd.hpp"
 
@@ -525,9 +526,9 @@
     // Assigns from an expression. See corresponding constructor.
     // Basic Guarantee: If the resolved T ctor throws, this is left UNINITIALIZED
     template<class Expr>
-    optional& operator= ( Expr expr )
+    optional& operator= ( Expr const& expr )
       {
-        this->assign_expr(expr,&expr);
+        this->assign_expr(expr,boost::addressof(expr));
         return *this ;
       }
 #endif