Compiler Error C2391

'identifier' : 'friend' cannot be used during type definition

The friend declaration includes a complete class declaration. A friend declaration can specify a member function or an elaborated type specifier, but not a complete class declaration.

The following sample generates C2326:

// C2391.cpp
// compile with: /c
class D {
   void func( int );

class A {
   friend class B { int i; };   // C2391

   // OK
   friend class C;
   friend void D::func(int);