Cannot initialize "BaseClass **" with an rvalue of type "DerivedClass **"

[moonman239]

Here's my code:
Bird *polly = new Bird();
Animal **pollyPtr = &bird;
The previous line is giving me the error in the title. Please tell me how I fi this. :)

[TarikNeaj]

Animal **pollyPtr = &bird;

What is "bird" ? Don't you mean polly?

[JLBorges]

> Cannot initialize "BaseClass **" with an rvalue of type "DerivedClass **"

There is no implicit conversion from 'pointer to pointer to derived class' to 'pointer to pointer to base class'.
(If it were to be allowed, it would crate a hole in the type system.)

struct animal { virtual ~animal() = default ; /* ... */ };
struct bird : animal { /* ... */ };

int main()
{
    bird b ;
    bird* pb = std::addressof(b) ;

    animal* pa = pb ; // fine: implicit conversion from bird* to animal*

    animal** ppa = std::addressof(pb) ; // *** error: no implicit conversion from bird** to animal**
}