Config lint request - check base class exists in scope

[PabstMirror]

class a {
    class x1;
};
class b: x1 {
};

ErrorMessage: File z\ace\addons\attach\CfgWeapons.hpp, line 22: .b: Undefined base class 'x1'
Application terminated intentionally

[BrettMayson]

Wait is that not a thing, how did I forget to do that, and nobody said anything about it

Yeah this already existed, I'll have to see if there are conditions in which it breaks