OOP52-CPP. Do not delete a polymorphic object without a virtual destructor

The C++ Standard, [expr.delete], paragraph 3 [ ISO/IEC 14882-2014 ], states the following:

In the first alternative ( delete object ), if the static type of the object to be deleted is different from its dynamic type, the static type shall be a base class of the dynamic type of the object to be deleted and the static type shall have a virtual destructor or the behavior is undefined. In the second alternative ( delete array ) if the dynamic type of the object to be deleted differs from its static type, the behavior is undefined.

Do not delete an object of derived class type through a pointer to its base class type that has a non- virtual destructor. Instead, the base class should be defined with a virtual destructor. Deleting an object through a pointer to a type without a virtual destructor results in undefined behavior .

Noncompliant Code Example

In this noncompliant example, b is a polymorphic pointer type whose static type is Base * and whose dynamic type is Derived * . When b is deleted, it results in undefined behavior because Base does not have a virtual destructor. The C++ Standard, [class.dtor], paragraph 4 [ ISO/IEC 14882-2014 ], states the following :

If a class has no user-declared destructor, a destructor is implicitly declared as defaulted. An implicitly declared destructor is an inline public member of its class.

The implicitly declared destructor is not declared as virtual even in the presence of other virtual functions.