Compiler Warning (level 3) C4570
'type' : is not explicitly declared as abstract but has abstract functions
A type that contains abstract functions should itself be marked as abstract.
Example
The following sample generates C4570.
// C4570.cpp
// compile with: /clr /W3 /c
ref struct X { // C4570
// try the following line instead
// ref class X abstract {
virtual void f() abstract;
};