https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93905
Jonathan Wakely <redi at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Keywords| |rejects-valid Status|WAITING |NEW Known to work| |8.2.0, 9.2.0 Summary|Cannot use Derived type of |[8 Regression] Cannot use |Base containing both enum |Derived type of Base |and protected destructor |containing both enum and | |protected destructor Known to fail| |8.3.0, 8.3.1 --- Comment #5 from Jonathan Wakely <redi at gcc dot gnu.org> --- Thank you. It only fails with -std=c++17 (which is exactly why you are supposed to tell us how you're compiling instead of making us guess).