"g++-6"   -fvisibility-inlines-hidden -std=c++14 -O2 -fPIC -m64 -pthread -O0 -fno-inline -Wall -fvisibility=hidden  -DBOOST_ALL_NO_LIB=1 -DBOOST_ASIO_DISABLE_DEV_POLL -DBOOST_ASIO_DISABLE_EPOLL -DBOOST_ASIO_DISABLE_IOCP -DBOOST_ASIO_DISABLE_KQUEUE -DBOOST_CHRONO_DYN_LINK=1 -DBOOST_CHRONO_NO_LIB=1 -DBOOST_COBALT_USE_STD_PMR=1 -DBOOST_CONTEXT_DYN_LINK=1 -DBOOST_DATE_TIME_DYN_LINK=1 -DBOOST_SYSTEM_DYN_LINK=1 -DBOOST_SYSTEM_NO_LIB=1 -DDATE_TIME_INLINE -D_GNU_SOURCE=1 -D_XOPEN_SOURCE=600   -I".." -I"/var/boost/run/boost_root/libs/asio/include" -I"/var/boost/run/boost_root/libs/assert/include" -I"/var/boost/run/boost_root/libs/chrono/include" -I"/var/boost/run/boost_root/libs/core/include" -I"/var/boost/run/boost_root/libs/integer/include" -I"/var/boost/run/boost_root/libs/move/include" -I"/var/boost/run/boost_root/libs/mp11/include" -I"/var/boost/run/boost_root/libs/predef/include" -I"/var/boost/run/boost_root/libs/ratio/include" -I"/var/boost/run/boost_root/libs/system/include" -I"/var/boost/run/boost_root/libs/throw_exception/include" -I"/var/boost/run/boost_root/libs/variant2/include" -I"/var/boost/run/boost_root/libs/winapi/include"  -c -o "/var/boost/run/results/boost/bin.v2/libs/asio/test/any_io_executor_select.test/gcc-6~c++14~O2/debug/x86_64/debug-symbols-off/threading-multi/visibility-hidden/any_io_executor.o" "../libs/asio/test/any_io_executor.cpp"

../libs/asio/test/any_io_executor.cpp: In static member function 'static constexpr boost::asio::execution::detail::blocking_t<>::never_t fat_executor::query(boost::asio::execution::blocking_t)':
../libs/asio/test/any_io_executor.cpp:63:3: error: the value of 'boost::asio::execution::detail::blocking_t<>::never' is not usable in a constant expression
   }
   ^
In file included from ../boost/asio/execution/any_executor.hpp:31:0,
                 from ../boost/asio/execution.hpp:19,
                 from ../boost/asio/any_io_executor.hpp:22,
                 from ../libs/asio/test/any_io_executor.cpp:17:
../boost/asio/execution/blocking.hpp:467:39: note: 'boost::asio::execution::detail::blocking_t<>::never' was not declared 'constexpr'
 const typename blocking_t<I>::never_t blocking_t<I>::never;
                                       ^~~~~~~~~~~~~