Config: detect ref convert bug in gcc 4.4 and 4.5

include/boost/none.hpp

@@ -1,5 +1,5 @@
 // Copyright (C) 2003, Fernando Luis Cacciola Carballal.
-// Copyright (C) 2014 Andrzej Krzemienski.
+// Copyright (C) 2014, 2015 Andrzej Krzemienski.
 //
 // Distributed under the Boost Software License, Version 1.0.
 // (See accompanying file LICENSE_1_0.txt or copy at

include/boost/none_t.hpp

@@ -1,5 +1,5 @@
 // Copyright (C) 2003, Fernando Luis Cacciola Carballal.
-// Copyright (C) 2014 Andrzej Krzemienski.
+// Copyright (C) 2014, 2015 Andrzej Krzemienski.
 //
 // Use, modification, and distribution is subject to the Boost Software
 // License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at

include/boost/optional/detail/optional_config.hpp

@@ -82,4 +82,18 @@
 
 #endif // defined(__GNUC__)
 
+#if defined(__GNUC__)
+// On some initial rvalue reference implementations GCC does it in a strange way,
+// preferring perfect-forwarding constructor to implicit copy constructor.
+
+# if (__GNUC__ == 4 && __GNUC_MINOR__ == 4)
+#  define BOOST_OPTIONAL_CONFIG_NO_PROPER_CONVERT_FROM_CONST_INT
+# endif
+
+# if (__GNUC__ == 4 && __GNUC_MINOR__ == 5)
+#  define BOOST_OPTIONAL_CONFIG_NO_PROPER_CONVERT_FROM_CONST_INT
+# endif
+
+#endif // defined(__GNUC__)
+
 #endif // header guard

test/Jamfile.v2

@@ -64,6 +64,8 @@ import testing ;
     [ run-fail optional_xconfig_NO_PROPER_ASSIGN_FROM_CONST_INT_fail.cpp ]
     [ run optional_xconfig_NO_PROPER_CONVERT_FROM_CONST_INT_pass.cpp ]
     [ run-fail optional_xconfig_NO_PROPER_CONVERT_FROM_CONST_INT_fail.cpp ]
+    [ run optional_xconfig_NO_LEGAL_CONVERT_FROM_REF_pass.cpp ]
+    [ compile-fail optional_xconfig_NO_LEGAL_CONVERT_FROM_REF_fail.cpp ]
     [ run optional_xconfig_HACK_TO_LIST_PREDEFINED_MACROS.cpp ]
   ;
 }

test/optional_xconfig_HACK_TO_LIST_PREDEFINED_MACROS.cpp

@@ -15,7 +15,7 @@
 int main()
 {
 #if defined(__GNUC__)
-  int empty = 0;
+  int empty = -1;
   BOOST_TEST_EQ(empty, __GNUC__);
   BOOST_TEST_EQ(empty, __GNUC_MINOR__);
   BOOST_TEST_EQ(empty, __GNUC_PATCHLEVEL__);

test/optional_xconfig_NO_LEGAL_CONVERT_FROM_REF_fail.cpp

@@ -0,0 +1,37 @@
+// Copyright (C) 2015 Andrzej Krzemienski.
+//
+// Use, modification, and distribution is subject to 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)
+//
+// See http://www.boost.org/lib/optional for documentation.
+//
+// You are welcome to contact the author at:
+//  akrzemi1@gmail.com
+
+#include "boost/core/ignore_unused.hpp"
+#include "boost/core/lightweight_test.hpp"
+#include "boost/optional/detail/optional_config.hpp"
+
+#ifndef BOOST_OPTIONAL_CONFIG_NO_LEGAL_CONVERT_FROM_REF
+
+static_assert(false, "failed as requested");
+
+#else
+
+struct S {};
+
+struct Binder
+{
+  S& ref_;
+  template <typename R> Binder (R&&r) : ref_(r) {}
+};
+
+int main()
+{
+  S s ;
+  Binder b = s;
+  boost::ignore_unused(b);
+}
+
+#endif

test/optional_xconfig_NO_LEGAL_CONVERT_FROM_REF_pass.cpp

@@ -0,0 +1,41 @@
+// Copyright (C) 2015 Andrzej Krzemienski.
+//
+// Use, modification, and distribution is subject to 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)
+//
+// See http://www.boost.org/lib/optional for documentation.
+//
+// You are welcome to contact the author at:
+//  akrzemi1@gmail.com
+
+#include "boost/core/ignore_unused.hpp"
+#include "boost/core/lightweight_test.hpp"
+#include "boost/optional/detail/optional_config.hpp"
+
+#ifndef BOOST_OPTIONAL_CONFIG_NO_LEGAL_CONVERT_FROM_REF
+
+struct S {};
+
+struct Binder
+{
+  S& ref_;
+  template <typename R> Binder (R&&r) : ref_(r) {}
+};
+
+int main()
+{
+  S s ; 
+  Binder b = s;
+  boost::ignore_unused(b);
+  return 0;
+}
+
+#else
+
+int main()
+{
+  return 0;
+}
+
+#endif