Hello all, I see the following Boost.Option regression test failures on develop branch: http://www.boost.org/development/tests/develop/developer/optional.html === error 1 === Test output: teeks99-02-dc3.7-14-Docker-64on64 - optional - optional_test_conversions_from_U / clang-gnu-linux-3.7~c++14 Rev 05c2033df7b99d19f4939bf81ca2aeeec592993d / Fri, 03 Nov 2017 00:24:42 +0000 Compile [2017-11-03 01:39:15 UTC]: fail "clang++-3.7" -c -x c++ -Wno-c99-extensions -std=c++14 -O0 -g -fno-inline -Wall -g -fPIC -m64 -DBOOST_ALL_NO_LIB=1 -I".." -o "/var/boost/run/results/boost/bin.v2/libs/optional/test/optional_test_conversions_from_U.test/clang-gnu-linux-3.7~c++14/debug/threadapi-pthread/optional_test_conversions_from_U.o" "../libs/optional/test/optional_test_conversions_from_U.cpp" In file included from ../libs/optional/test/optional_test_conversions_from_U.cpp:12: In file included from ../boost/optional/optional.hpp:64: ../boost/optional/detail/optional_config.hpp:152:48: error: expected value in expression # if BOOST_WORKAROUND(BOOST_GCC, >= 50000) && ^ 1 error generated. === error 2 === Test output: teeks99-02-dc5-1z-lc-Docker-64on64 - optional - optional_test_conversions_from_U / clang-gnu-linux-5.0~c++1z~lc Rev 420dd51fb237f5e75cae0aeb01ec427717e4a748 / Sat, 04 Nov 2017 15:00:43 +0000 Compile [2017-11-04 15:49:56 UTC]: fail "clang++-5.0" -c -x c++ -Wno-c99-extensions -std=c++1z -stdlib=libc++ -isystem/usr/include/libcxxabi -O0 -g -fno-inline -Wall -g -fPIC -m64 -DBOOST_ALL_NO_LIB=1 -I".." -o "/var/boost/run/results/boost/bin.v2/libs/optional/test/optional_test_conversions_from_U.test/clang-gnu-linux-5.0~c++1z~lc/debug/threadapi-pthread/optional_test_conversions_from_U.o" "../libs/optional/test/optional_test_conversions_from_U.cpp" In file included from ../libs/optional/test/optional_test_conversions_from_U.cpp:18: In file included from ../boost/core/lightweight_test.hpp:25: In file included from /usr/include/c++/v1/iostream:38: In file included from /usr/include/c++/v1/ios:216: In file included from /usr/include/c++/v1/__locale:15: /usr/include/c++/v1/string:1942:14: error: expected ';' at end of declaration _NOEXCEPT ^ /usr/include/c++/v1/string:1947:9: error: expected unqualified-id _NOEXCEPT ^ /usr/include/c++/v1/__config:368:21: note: expanded from macro '_NOEXCEPT' # define _NOEXCEPT noexcept ^ 2 errors generated. === The first error only shows on develop, the second error shows up on both develop and master regression tests. Do you know what the issue is on this toolset/platform? I am asking because Boost.Contract uses Boost.Option so it is showing the same failures. Thank you. --Lorenzo