Plugin package error with "template class" argument list missing after assumed function template

[AltBurn]

Hi, I’m working on developing my own game framework and currently experimenting with plugins and packages.

I encountered an error in my header file that says, “argument list missing after assumed function template ‘TQueue’.” The error seems to be related to the following line:

#include "CoreMinimal.h"

class FGOAPAction;
class GOAP_API FGOAPlanner
{
public:
	FGOAPlanner();
	~FGOAPlanner();

    TQueue<TUniquePtr<FGOAPAction>> Plan(); // Error line
};

cpp

#include "GOAPlanner.h"
#include "GOAPAction.h"

TQueue<TUniquePtr<FGOAPAction>> FGOAPlanner::Plan() // error line
{
    return TQueue<TUniquePtr<FGOAPAction>>();
}

I have already defined the FGOAPAction class in another file, but for some reason, the compiler is unable to find it. Any insights into why this class is not being recognized would be greatly appreciated.

[AltBurn]

After writing, I spent a few hours resolving this issue. I want to share my solution here for those facing the same problem.

Initially, I searched for TQueue in the Unreal documentation and found that it is included in Containers/Queue.h.

While my header included CoreMinimal.h, it did not contain Containers/Queue.h. Therefore, I resolved the problem by adding Containers/Queue.h to my error header.

Thank you for reading. If you encounter the same issue, I hope this information proves helpful.

I am also curious as to why Visual Studio did not show an error for this. Perhaps some header files have a forward declaration for TQueue.