> A function which expects a `base* ` can already be passed a `derived* ` without any problems. Doing the same for a collection of `base* ` to a collection of `

> A function which expects a `base* ` can already be passed a `derived* ` without any problems. Doing the same for a collection of `base* ` to a collection of `derived* ` is not fundamentally different Since C++ has multiple inheritance, derived* differs from base* not just by reinterpretation, the pointer value could be different. A single pointer can trivially be adjusted, but a heap-allocated, potentially huge array of pointers would require an equally huge heap allocation to store the adjusted pointers.