delete[] undefined result

abc.cpp

#include<cstdio>

using namespace std;

class Base
{
public:
    virtual ~Base() {}
};

#define IMPLEMENT_DERIVED_FREE(CLASS_NAME)                                         \
      static void FreePool( Base *basePtr )                                        \
      {                                                                            \
          CLASS_NAME *derivedPtr = reinterpret_cast<CLASS_NAME*>(basePtr);         \
          delete [] derivedPtr;                                                    \
      }                                                                            \


class Derived : public Base
{
public:
    IMPLEMENT_DERIVED_FREE(Derived);

    float bar; // This pads it, and it crashes.  Undefined result either way.


};

int main( void )
{
    Base *ptr = new Derived[10];   // BUG BUG
    delete []ptr;
    
    return 0;
}