Why does incomplete type of smart pointer data member and raw pointer data member have different behavior when their parent destruct?

In the following code:

smart pointer data member pImpl(class Impl) and raw pointer pc(class CAT) all are incomplete data type, there is no definition of these two classes in Widget.h

//widget.h

#ifndef W_H_
#define W_H_
#include <memory>

class Widget { 
    public:
        Widget();
        ~Widget() {    //
            delete pc; // I know I should put ~Widget to .cpp
                       // I just want to show the difference in behavior
                       // between raw pointer and smart pointer(both has incomplete type)
                       // when widget object destructs 
        }
    private:
        struct Impl; 
        std::shared_ptr<Impl> pImpl;  // use smart pointer
        struct CAT;
        CAT *pc;  //raw pointer
};
#endif

//widget.cpp

#include "widget.h"

#include <string>
#include <vector>
#include <iostream>
using namespace std;
struct Widget::CAT 
{
    std::string name;
    CAT(){cout<<"CAT"<<endl;}
    ~CAT(){cout<<"~CAT"<<endl;}
};      


struct Widget::Impl {
    std::string name;
    Impl(){cout<<"Impl"<<endl;}
    ~Impl(){cout<<"~Impl"<<endl;}
};


Widget::Widget()  
    : pImpl(std::make_shared<Impl>()),
      pc(new CAT)
{} 

//main.cpp

#include "widget.h"
int main()
{
    Widget w;
}

//output

Impl

CAT

~Impl

For the raw pointer data member, its destuctor is not called when widget object is destructed.

While the shared_ptr data member, its destructor has been correctly called.

To my understanding, in Widget::~Widget() it should generate some code automatically as the following:

        ~Widget() {
            delete pc; // wrote by me

            // generated by compiler
            delete pImpl->get();
        }

Why do shared_ptr data member and raw data member have different behavior when the widget gets destructed?

I test the code using g++4.8.2 in Linux

================================EDIT=============================== According to the answers, the reason is because of :

the code generated by compiler is NOT:

        ~Widget() {
            delete pc; // wrote by me

            // generated by compiler
            delete pImpl->get();
        }

it maybe something like:

        ~Widget() {
            delete pc; // wrote by me

            // generated by compiler
            pimpl.deleter(); //deleter will be initailized while pimpl object is initialized
        }