Circular declarations

Hi,
>
I'm using VC++ 2008 Express.
>
I have a managed interface. One of it's member uses a type that is declared
later in the same file. The type implements the interface declared before.
So, I have circular relations between the two declarations.
Question: How do I have to forward-declare the struct? (C++ is still not
clever enough to see the declaration below.)
>
public interface class IMatrixSource
{
Matrix GetMatrix(); // error: unknown type
};
>
>
public value struct Matrix: IMatrixSource
{
public:
//.....
private:
Matrix GetValue() = IMatrixSource::GetValue;
};
>
>
If I write "ref struct Matrix;" above the interface declaration, the
compiler says C3816, "'struct Matrix' was previously declared or defined
with a different managed modifier" at the later declaration. What is the
correct syntax?

>
Armin:
>
If Matrix is a value struct, it might be a good idea to forward declare it
as a value struct.