[Boost-bugs] [Boost C++ Libraries] #10684: Implicit conversion warnings when using clang's -Wconversion flag.

Subject: [Boost-bugs] [Boost C++ Libraries] #10684: Implicit conversion warnings when using clang's -Wconversion flag.
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2014-10-21 21:09:35

#10684: Implicit conversion warnings when using clang's -Wconversion flag.
------------------------------+--------------------------
 Reporter:  anonymous         |      Owner:  rogeeff
     Type:  Bugs              |     Status:  new
Milestone:  To Be Determined  |  Component:  test
  Version:  Boost 1.56.0      |   Severity:  Optimization
 Keywords:                    |
------------------------------+--------------------------
 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/test/unit_test.hpp>

 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<CharT1,Tr>( 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<const char>::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<const
 char>::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<const char>::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<CharT1,Tr>( 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<<<char, std::__1::char_traits<char>, 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<const
 boost::unit_test::basic_cstring<const char> &>::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.
 $
 }}}

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/10684>
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