id,summary,reporter,owner,description,type,status,milestone,component,version,severity,resolution,keywords,cc 10684,Implicit conversion warnings when using clang's -Wconversion flag.,anonymous,Gennadiy Rozental,"Operating system: OS X 10.10 Compiler: {{{ $ clang++ --version Apple LLVM version 6.0 (clang-600.0.54) (based on LLVM 3.5svn) Target: x86_64-apple-darwin14.0.0 Thread model: posix $ }}} Boost: 1.56.0 The following code (assumed to be in a file named clang_warning.cpp): {{{ #!c++ // clang_warning.cpp: #define BOOST_TEST_MODULE Test #include BOOST_AUTO_TEST_CASE(test) { BOOST_CHECK(true); } }}} when compiled using the -Wconversion flag (and Boost under /opt/boost_1_56_0/) like: {{{ $ clang++ -Wconversion -I/opt/boost_1_56_0/ clang_warning.cpp -lboost_test_exec_monitor }}} gives implicit conversion warnings like: {{{ /opt/boost_1_56_0/boost/test/utils/basic_cstring/bcs_char_traits.hpp:90:20: warning: implicit conversion changes signedness: 'long' to 'std::size_t' (aka 'unsigned long') [-Wsign-conversion] return ptr - cstr; ~~~~~~ ~~~~^~~~~~ }}} {{{ /opt/boost_1_56_0/boost/test/utils/basic_cstring/basic_cstring.hpp:232:18: warning: implicit conversion changes signedness: 'long' to 'size_type' (aka 'unsigned long') [-Wsign-conversion] return m_end - m_begin; ~~~~~~ ~~~~~~^~~~~~~~~ }}} {{{ /opt/boost_1_56_0/boost/test/utils/basic_cstring/io.hpp:55:50: warning: implicit conversion changes signedness: 'long' to 'size_type' (aka 'unsigned long') [-Wsign-conversion] os << std::basic_string( beg, end - beg ); ~~~ ~~~~^~~~~ }}} The full output is below: {{{ $ clang++ -Wconversion -I/opt/boost_1_56_0/ clang_warning.cpp -lboost_test_exec_monitor In file included from clang_warning.cpp:4: In file included from /opt/boost_1_56_0/boost/test/unit_test.hpp:19: In file included from /opt/boost_1_56_0/boost/test/test_tools.hpp:19: In file included from /opt/boost_1_56_0/boost/test/predicate_result.hpp:21: In file included from /opt/boost_1_56_0/boost/test/utils/basic_cstring/basic_cstring.hpp:21: /opt/boost_1_56_0/boost/test/utils/basic_cstring/bcs_char_traits.hpp:90:20: warning: implicit conversion changes signedness: 'long' to 'std::size_t' (aka 'unsigned long') [-Wsign-conversion] return ptr - cstr; ~~~~~~ ~~~~^~~~~~ /opt/boost_1_56_0/boost/test/utils/basic_cstring/basic_cstring.hpp:182:40: note: in instantiation of member function 'boost::unit_test::ut_detail::bcs_char_traits_impl::length' requested here , m_end ( m_begin + (s ? traits_type::length( s ) : 0 ) ) ^ /opt/boost_1_56_0/boost/test/unit_test_suite_impl.hpp:158:41: note: in instantiation of member function 'boost::unit_test::basic_cstring::basic_cstring' requested here master_test_suite_t() : test_suite( ""Master Test Suite"" ) ^ In file included from clang_warning.cpp:4: In file included from /opt/boost_1_56_0/boost/test/unit_test.hpp:19: In file included from /opt/boost_1_56_0/boost/test/test_tools.hpp:19: In file included from /opt/boost_1_56_0/boost/test/predicate_result.hpp:21: /opt/boost_1_56_0/boost/test/utils/basic_cstring/basic_cstring.hpp:232:18: warning: implicit conversion changes signedness: 'long' to 'size_type' (aka 'unsigned long') [-Wsign-conversion] return m_end - m_begin; ~~~~~~ ~~~~~~^~~~~~~~~ /opt/boost_1_56_0/boost/test/framework.hpp:90:86: note: in instantiation of member function 'boost::unit_test::basic_cstring::size' requested here internal_error( const_string m ) : std::runtime_error( std::string( m.begin(), m.size() ) ) {} ^ In file included from clang_warning.cpp:4: In file included from /opt/boost_1_56_0/boost/test/unit_test.hpp:19: In file included from /opt/boost_1_56_0/boost/test/test_tools.hpp:28: /opt/boost_1_56_0/boost/test/utils/basic_cstring/io.hpp:55:50: warning: implicit conversion changes signedness: 'long' to 'size_type' (aka 'unsigned long') [-Wsign-conversion] os << std::basic_string( beg, end - beg ); ~~~ ~~~~^~~~~ /opt/boost_1_56_0/boost/test/utils/lazy_ostream.hpp:74:29: note: in instantiation of function template specialization 'boost::unit_test::operator<<, const char>' requested here return m_prev(ostr) << m_value; ^ clang_warning.cpp:8:5: note: in instantiation of member function 'boost::unit_test::lazy_ostream_impl &>::operator()' requested here BOOST_CHECK(true); ^ /opt/boost_1_56_0/boost/test/test_tools.hpp:110:45: note: expanded from macro 'BOOST_CHECK' #define BOOST_CHECK( P ) BOOST_CHECK_IMPL( (P), BOOST_TEST_STRINGIZE( P ), CHECK, CHECK_PRED ) ^ /opt/boost_1_56_0/boost/test/test_tools.hpp:91:5: note: expanded from macro 'BOOST_CHECK_IMPL' BOOST_TEST_TOOL_IMPL( check_impl, P, check_descr, TL, CT ), 0 );\ ^ /opt/boost_1_56_0/boost/test/test_tools.hpp:79:9: note: expanded from macro 'BOOST_TEST_TOOL_IMPL' ::boost::unit_test::lazy_ostream::instance() << check_descr, \ ^ 3 warnings generated. $ }}}",Bugs,closed,Boost 1.59.0,test,Boost 1.56.0,Optimization,fixed,,