In D I have an extern(C++) class:
```cpp
extern(C++) class A
{
~this();
// other stuff
}
```
An a function that takes A by const reference:
```cpp
void CppFunc(const A& arg);
```
But how do I bind this in D ?
```cpp
extern(C++) void CppFunc(A arg); // tries to pass as 'A*'
extern(C++) void CppFunc(ref const(A) arg); // tries to pass as
'A const * const &'
```
I have solved similar problems with other classes by declaring
them as struct in D, but that only works for classes that have no
virtual functions. I now have a class where I do need to use a
class on the D side, and now I have problems passing these
objects to C++.
