In file included from boost_test_double_trouble_under_clang.cpp:3:
In file included from /tmp/test/include/boost/test/included/unit_test.hpp:34:
In file included from /tmp/test/include/boost/test/unit_test.hpp:18:
In file included from /tmp/test/include/boost/test/test_tools.hpp:38:
In file included from /tmp/test/include/boost/test/tools/old/impl.hpp:21:
/tmp/test/include/boost/test/tools/floating_point_comparison.hpp:259:25: error: 'mutable' cannot be applied to references
    mutable FPT         m_tested_rel_diff;
                        ^
/tmp/test/include/boost/test/tools/fpc_op.hpp:71:34: note: in instantiation of template class 'boost::math::fpc::close_at_tolerance<const double &&>' requested here
    fpc::close_at_tolerance<FPT> P( fpc_tolerance<FPT>(), fpc::FPC_STRONG );
                                 ^
/tmp/test/include/boost/test/tools/fpc_op.hpp:211:30: note: in instantiation of function template specialization 'boost::test_tools::assertion::op::compare_fpv<const double &&, double, double, boost::test_tools::assertion::op::EQ<const double, double, void> >' requested here
BOOST_TEST_FOR_EACH_COMP_OP( DEFINE_FPV_COMPARISON )
                             ^
/tmp/test/include/boost/test/tools/assertion.hpp:71:5: note: expanded from macro 'BOOST_TEST_FOR_EACH_COMP_OP'
    action( ==, EQ, != )                    \
    ^
/tmp/test/include/boost/test/tools/fpc_op.hpp:192:16: note: expanded from macro 'DEFINE_FPV_COMPARISON'
        return compare_fpv<FPT>(lhs, rhs, (OP*)0);                      \
               ^
/tmp/test/include/boost/test/tools/assertion.hpp:348:20: note: in instantiation of member function 'boost::test_tools::assertion::op::EQ<const double, double, void>::eval' requested here
        return OP::eval( m_lhs.value(), m_rhs );
                   ^
/tmp/test/include/boost/test/tools/assertion.hpp:357:42: note: in instantiation of member function 'boost::test_tools::assertion::binary_expr<boost::test_tools::assertion::value_expr<const double &>, double, boost::test_tools::assertion::op::EQ<const double, double, void> >::value' requested here
        assertion_result const expr_res( value() );
                                         ^
boost_test_double_trouble_under_clang.cpp:7:2: note: in instantiation of member function 'boost::test_tools::assertion::binary_expr<boost::test_tools::assertion::value_expr<const double &>, double, boost::test_tools::assertion::op::EQ<const double, double, void> >::evaluate' requested here
        BOOST_TEST( num == 0.0 );
        ^
/tmp/test/include/boost/test/tools/interface.hpp:166:8: note: expanded from macro 'BOOST_TEST'
    2, BOOST_TEST_TOOL_UNIV, BOOST_TEST_TOOL_UNIV_EX, CHECK, __VA_ARGS__ )  \
       ^
/tmp/test/include/boost/test/detail/pp_variadic.hpp:38:13: note: expanded from macro 'BOOST_TEST_INVOKE_IF_N_ARGS'
            F1,                                                     \
            ^
/opt/include/boost/preprocessor/control/iif.hpp:18:57: note: expanded from macro 'BOOST_PP_IIF'
#    define BOOST_PP_IIF(bit, t, f) BOOST_PP_IIF_I(bit, t, f)
                                                        ^
note: (skipping 2 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
/tmp/test/include/boost/test/detail/pp_variadic.hpp:27:51: note: expanded from macro 'BOOST_TEST_INVOKE_VARIADIC'
#  define BOOST_TEST_INVOKE_VARIADIC( tool, ... ) tool (__VA_ARGS__)
                                                  ^
/tmp/test/include/boost/test/tools/interface.hpp:144:5: note: expanded from macro 'BOOST_TEST_TOOL_UNIV'
    BOOST_TEST_TOOL_ET_IMPL( P, level )                                     \
    ^
/tmp/test/include/boost/test/tools/interface.hpp:81:9: note: expanded from macro 'BOOST_TEST_TOOL_ET_IMPL'
      E.evaluate(),                                             \
        ^
1 error generated.