https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67747
--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> --- Could you modify the test to print the values of iter->path() and p/"d1" to stdout before the assertion on line 52? e.g. __builtin_puts( iter->path().native().c_str() ); __builtin_puts( (p/"d1").native().c_str() );