https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90646
--- Comment #5 from Jonathan Wakely <redi at gcc dot gnu.org> --- Is it possible you're mixing code compiled with GCC 8 and GCC 9? In general that works, but not for the new C++17 components that were still experimental in GCC 8, such as filesystem::path. Valgrind might give you more information about the crash, to help debug the problem.
