Add sv_common_reference_test

test/Jamfile.v2

@@ -306,6 +306,7 @@ run sv_lt_test.cpp ;
 run sv_stream_insert_test.cpp ;
 run sv_conversion_test.cpp ;
 run sv_conversion_test2.cpp : ;
+run sv_common_reference_test.cpp ;
 
 run span_test.cpp ;
 run span_types_test.cpp ;

test/sv_common_reference_test.cpp

@@ -0,0 +1,48 @@
+// Copyright 2021 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/core/detail/string_view.hpp>
+#include <boost/core/lightweight_test_trait.hpp>
+#include <boost/config/pragma_message.hpp>
+#include <boost/config.hpp>
+#include <string>
+
+#if BOOST_CXX_VERSION < 202000L
+
+BOOST_PRAGMA_MESSAGE( "Skipping test because BOOST_CXX_VERSION is " BOOST_STRINGIZE(BOOST_CXX_VERSION) )
+int main() {}
+
+#else
+
+#include <version>
+
+#if !defined(__cpp_lib_concepts)
+
+BOOST_PRAGMA_MESSAGE( "Skipping test because __cpp_lib_concepts is not defined" )
+int main() {}
+
+#elif __cpp_lib_concepts < 201907L
+
+BOOST_PRAGMA_MESSAGE( "Skipping test because __cpp_lib_concepts is " BOOST_STRINGIZE(__cpp_lib_concepts) )
+int main() {}
+
+#else
+
+#include <type_traits>
+
+using T = std::common_reference_t< boost::core::string_view&&, std::string& >;
+
+static_assert( std::common_reference_with< boost::core::string_view&&, std::string& > );
+static_assert( std::common_reference_with< boost::core::wstring_view&&, std::wstring const& > );
+
+int main()
+{
+    BOOST_TEST_TRAIT_SAME( std::common_reference_t< boost::core::string_view&&, std::string& >, boost::core::string_view );
+    BOOST_TEST_TRAIT_SAME( std::common_reference_t< boost::core::wstring_view&&, std::wstring const& >, boost::core::wstring_view );
+
+    return boost::report_errors();
+}
+
+#endif
+#endif