Hi Devs, consider below boost testcase, boost_1_70_0/libs/fusion/test/functional/invoke.cpp when compiles with optimization enabled, $g++ -O2 -I./boost_1_70_0 boost_1_70_0/libs/fusion/test/functional/invoke.cpp $./a.out ./boost_1_70_0/libs/fusion/test/functional/invoke.cpp(391): test 'that.data == fusion::invoke(& members::data, fusion::join(sv_obj_c_ctx,seq))' failed in function 'void test_sequence_n(Sequence&, mpl_::int_<0>) [with Sequence = boost::fusion::vector<>]' ./boost_1_70_0/libs/fusion/test/functional/invoke.cpp(401): test 'that.data == fusion::invoke(& members::data, fusion::join(sv_obj_c_d_ctx,seq))' failed in function 'void test_sequence_n(Sequence&, mpl_::int_<0>) [with Sequence = boost::fusion::vector<>]' ./boost_1_70_0/libs/fusion/test/functional/invoke.cpp(391): test 'that.data == fusion::invoke(& members::data, fusion::join(sv_obj_c_ctx,seq))' failed in function 'void test_sequence_n(Sequence&, mpl_::int_<0>) [with Sequence = boost::fusion::list<>]' ./boost_1_70_0/libs/fusion/test/functional/invoke.cpp(401): test 'that.data == fusion::invoke(& members::data, fusion::join(sv_obj_c_d_ctx,seq))' failed in function 'void test_sequence_n(Sequence&, mpl_::int_<0>) [with Sequence = boost::fusion::list<>]' 4 errors detected. And When compiled without any optimization $g++ -O0 -I./boost_1_70_0 boost_1_70_0/libs/fusion/test/functional/invoke.cpp $./a.out No errors detected. $g++ --version Target: x86_64-pc-linux-gnu Configured with: ../gcc-9.1.0/configure -- --enable-languages=c,c++ --disable-libquadmath --disable-libquadmath-support --disable-werror --disable-bootstrap --enable-gold Thread model: posix gcc version 9.1.0 (GCC) Here we demonstrated the test case with g++ but same can be seen with clang++. When analyzed further we have seen that this is [ boost_1_70_0/boost/fusion/functional/invocation/invoke.hpp:139 ] trying to return local address, which is undefined behavior. And that lead to above test-case failure. So either we have to modify test-case to pass as reference or disable it.But before going ahead like to know your thought/suggestions? Thanks, Jaydeep