https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90276
--- Comment #6 from Jonathan Wakely <redi at gcc dot gnu.org> --- Some of the tests FAIL for different reasons: /home/jwakely/src/gcc/build/x86_64-pc-linux-gnu/libstdc++-v3/include/bits/stl_algo.h:2051: In function: _FIter std::upper_bound(_FIter, _FIter, const _Tp&, _Compare) [with _FIter = gnu_debug::_Safe_iterator<gnu_cxx::normal_iterator<Num<float>*, vector<Num<float>, allocator<Num<float> > > >, debug::vector<Num<float>, allocator<Num<float> > >, random_access_iterator_tag>; _Tp = Num<float>; _Compare = main()::<lambda(Num<float>, Num<float>)>] Error: elements in iterator range [first, last) are not partitioned by the predicate __comp and value __val. Objects involved in the operation: iterator "first" @ 0x7ffda0426810 { type = gnu_cxx::normal_iterator<Num<float>*, std::vector<Num<float>, std::allocator<Num<float> > > > (mutable iterator); state = dereferenceable (start-of-sequence); references sequence with type 'std::debug::vector<Num<float>, std::allocator<Num<float> > >' @ 0x7ffda0427730 } iterator "last" @ 0x7ffda0426840 { type = gnu_cxx::normal_iterator<Num<float>*, std::vector<Num<float>, std::allocator<Num<float> > > > (mutable iterator); state = dereferenceable; references sequence with type 'std::debug::vector<Num<float>, std::allocator<Num<float> > >' @ 0x7ffda0427730 } FAIL: 25_algorithms/pstl/alg_sorting/partial_sort.cc -std=gnu++17 execution test