Fix #1106.

[SVN r45068]

test/ip_convertible_test.cpp

@@ -0,0 +1,54 @@
+#include <boost/config.hpp>
+
+//  wp_convertible_test.cpp
+//
+//  Copyright (c) 2008 Peter Dimov
+//
+//  Distributed under the Boost Software License, Version 1.0.
+//  See accompanying file LICENSE_1_0.txt or copy at
+//  http://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/detail/lightweight_test.hpp>
+#include <boost/intrusive_ptr.hpp>
+
+//
+
+struct W
+{
+};
+
+void intrusive_ptr_add_ref( W* )
+{
+}
+
+void intrusive_ptr_release( W* )
+{
+}
+
+struct X: public virtual W
+{
+};
+
+struct Y: public virtual W
+{
+};
+
+struct Z: public X
+{
+};
+
+int f( boost::intrusive_ptr<X> )
+{
+    return 1;
+}
+
+int f( boost::intrusive_ptr<Y> )
+{
+    return 2;
+}
+
+int main()
+{
+    BOOST_TEST( 1 == f( boost::intrusive_ptr<Z>() ) );
+    return boost::report_errors();
+}