struct Base
{
  int member;
};

struct Derived : Base
{
  int another_member;
};

int main()
{
  Base* p = new Derived[10]; // (1)
  p[1].member = 42; // (2)
  delete[] p; // (3)
}

根据标准(1)是格式正确的,因为Dervied *(这是新表达式的结果)可以隐式转换为Base *(C11草案,§4.10/ 3)：

A prvalue of type “pointer to cv D”,where D is a class type,can be
converted to a prvalue of type “pointer to cv B”,where B is a base
class (Clause 10) of D. If B is an inaccessible (Clause 11) or
ambiguous (10.2) base class of D,a program that necessitates this
conversion is ill-formed. The result of the conversion is a pointer to
the base class subobject of the derived class object. The null pointer
value is converted to the null pointer value of the destination type.

(3)由于§5.3.5/ 3导致未定义的行为：

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.

(2)是否符合标准,否则会导致程序不合格或未定义的行为？

编辑：更好的措辞