You can’t forward declare a struct that is used as a non-pointer (since the size of the struct must be known at compile time) and you cannot tag a struct pointer as UPROPERTY, so you must put that struct on a .h file and include it in your header.
You can’t forward declare a struct that is used as a non-pointer (since the size of the struct must be known at compile time) and you cannot tag a struct pointer as UPROPERTY, so you must put that struct on a .h file and include it in your header.