[Boost-commit] svn:boost r85104 - in trunk: boost/type_traits libs/type_traits/test

Subject: [Boost-commit] svn:boost r85104 - in trunk: boost/type_traits libs/type_traits/test
From: antoshkka_at_[hidden]
Date: 2013-07-22 08:51:09

Author: apolukhin
Date: 2013-07-22 08:51:09 EDT (Mon, 22 Jul 2013)
New Revision: 85104
URL: http://svn.boost.org/trac/boost/changeset/85104

Log:
Unify behavior of is_copy_constructible triat when dealing with rvalues + add comments for some tests (refs #8802):

Text files modified: 
   trunk/boost/type_traits/is_copy_constructible.hpp          |     9 ++++++---                               
   trunk/libs/type_traits/test/is_copy_constructible_test.cpp |    20 ++++++++++++++++++--                    
   2 files changed, 24 insertions(+), 5 deletions(-)

Modified: trunk/boost/type_traits/is_copy_constructible.hpp
==============================================================================
--- trunk/boost/type_traits/is_copy_constructible.hpp	Mon Jul 22 07:50:26 2013	(r85103)
+++ trunk/boost/type_traits/is_copy_constructible.hpp	2013-07-22 08:51:09 EDT (Mon, 22 Jul 2013)	(r85104)
@@ -13,6 +13,7 @@
 #include <boost/type_traits/detail/yes_no_type.hpp>
 #include <boost/type_traits/is_base_and_derived.hpp>
 #include <boost/type_traits/add_reference.hpp>
+#include <boost/type_traits/is_rvalue_reference.hpp>
 #include <boost/utility/declval.hpp>
 #include <boost/noncopyable.hpp>
 
@@ -67,9 +68,11 @@
     //          ...
     //      };
     BOOST_STATIC_CONSTANT(bool, value = (
-        sizeof(test(
-            boost::declval<BOOST_DEDUCED_TYPENAME boost::add_reference<T>::type>()
-        )) == sizeof(boost::type_traits::yes_type)
+            sizeof(test(
+                boost::declval<BOOST_DEDUCED_TYPENAME boost::add_reference<T>::type>()
+            )) == sizeof(boost::type_traits::yes_type)
+        ||
+            boost::is_rvalue_reference<T>::value
     ));
 };
 

Modified: trunk/libs/type_traits/test/is_copy_constructible_test.cpp
==============================================================================
--- trunk/libs/type_traits/test/is_copy_constructible_test.cpp	Mon Jul 22 07:50:26 2013	(r85103)
+++ trunk/libs/type_traits/test/is_copy_constructible_test.cpp	2013-07-22 08:51:09 EDT (Mon, 22 Jul 2013)	(r85104)
@@ -259,11 +259,27 @@
 
 BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_copy_constructible<int&>::value, true);
 #ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
-BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_copy_constructible<int&&>::value, false);
+// Code like `int&& a = 10;` or 
+//      struct nonc {
+//          nonc() = default;
+//          nonc(const nonc&) = delete;
+//          nonc(nonc&&) = delete;
+//          nonc& operator=(const nonc&) = delete;
+//          nonc& operator=(nonc&&) = delete;
+//      };
+//
+//      nonc && a = nonc();
+// is legal in C++11. so this trait MUST return true.
+BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_copy_constructible<int&&>::value, true);
 #endif
 BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_copy_constructible<const int&>::value, true);
 
-// Following three tests may give different results because of copiler and C++03/C++11
+
+// Following three tests may give different results because of compiler and C++03/C++11.
+// On C++11 compiler following code:
+//      int c[2][4][5][6][3];
+//      int b[2][4][5][6][3] = std::move(c);
+// does not compile, so we expect `false` to be the result of those three tests.
 BOOST_CHECK_SOFT_INTEGRAL_CONSTANT(::tt::is_copy_constructible<int[2]>::value, false, true);
 BOOST_CHECK_SOFT_INTEGRAL_CONSTANT(::tt::is_copy_constructible<int[3][2]>::value, false, true);
 BOOST_CHECK_SOFT_INTEGRAL_CONSTANT(::tt::is_copy_constructible<int[2][4][5][6][3]>::value, false, true);