https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121614
--- Comment #10 from Sam Gardner <samuelgardner101 at gmail dot com> --- Have refactored; due to forward declarations, I define a lot inside `extern "C++"`, which I now have to include in the .cpp file as-well as the .ixx files. This works fine. >From what I understand, the destructor issue is to do with "key functions". For example, if I define a different virtual method and implement it in the header file, like `virtual auto _spp_key_function() const -> void;` then the class's destructor can go in the .cpp file. So it wasn't a destructor problem, more a virtual function problem, that just happened to be the destructors as they are virtual. Still kind of feel the dummy functions as key functions is a bit hacky, but it lets me move the destructors into the .cpp files and not have to import stuff into the .ixx files.
