Will using delete with a base class pointer cause a memory leak?

Question

Given two classes have only primitive data type and no custom destructor/deallocator. Does C++ spec guarantee it will deallocate with correct size?

struct A { in         


        

Answer 1

Unless the base class destructor is virtual, it's undefined behaviour. See 5.3.5/4:

If the static type of the operand [of the delete operator] is different from its dynamic type, the static type shall be a base class of the operand's dynamic type and the static type shall have a virtual destructor or the behaviour is undefined.