optional_test_fail_convert_from_null
../libs/optional/test/optional_test_fail_convert_from_null.cpp:22:35: warning: unused variable 'opt' [-Wunused-variable]
optional_test_inplace_fail2
../boost/utility/typed_in_place_factory.hpp:57:12: warning: left operand of comma operator has no effect [-Wunused-value]
optional_test_ref_fail3
../libs/optional/test/optional_test_ref_fail3.cpp:20:25: warning: unused variable 'opt2' [-Wunused-variable]