object 'class' can never be instantiated - user-defined constructor required
The class has no user-defined or default constructors. No instantiation is performed. The following sample generates C4610:
struct A { int &j; A& A::operator=( const A& ); }; // C4610 /* use this structure definition to resolve the warning struct B { int &k; B(int i = 0) : k(i) { } B& B::operator=( const B& ); } b; */ void main() { }