FStructTracker

The TScriptStructTypeBitSet holds information on "existence" of subtypes of a given UStruct. The information on available child-structs is gathered lazily - the internal FStructTracker is assigning a given type a new index the very first time the type is encountered. To create a specific instantiation of the type you need to declare the static StructTracker member variable. To do it for an arbitrary type FFooBar add the following in your header or cpp file:

DECLARE_STRUCTTYPEBITSET(FMyFooBarBitSet, FFooBar);

where FMyFooBarBitSet is the alias of the type you can use in your code. To have your type exposed to other modules use DECLARE_STRUCTTYPEBITSET_EXPORTED, like so:

DECLARE_STRUCTTYPEBITSET_EXPORTED(MYMODULE_API, FMyFooBarBitSet, FFooBar);

The type contains static members so you'll also need to define these. You can easily do it by placing the following in your cpp file (continuing the FFooBar example):

DEFINE_STRUCTTYPEBITSET(FMyFooBarBitSet);