MISRA C++:2008 Rule 10-3-3

class Conic{
	//...
	public:
	double centerAbscissa;
	double centerOrdinate;
	//..
	virtual double  getArea()=0;
};
class Circle: public Conic{
	//...
	public:
	//...
	double getArea() override{
		//calculate area of circle
	}
};
class Ellipse: public Circle{
	//...
	public:
	//...
	virtual double getArea()=0; //Noncompliant
};

In this example, the base class Conic is an abstract class because the function getArea() is a pure virtual function. The derived class Circle implements the function getArea. The expectation from such a polymorphic hierarchy is that the virtual function getArea calculates the area correctly based on the derived class. When the derived class Ellipse redeclares getArea as a pure virtual function, the derived class Ellipse becomes abstract and the function Ellipse.getArea() cannot be invoked. Developers might expect Ellipse.getArea() to return the area of the ellipse. Because this redeclaration as a pure virtual function does not meet developer expectation, Polyspace flags the declaration.