copy constructor do not work in cpp template - c++11

Question

I'm writing a test program about c++ type erasure, the code is put on the end.
when I run program , the test case 2 output as follow:
A default cstr...0x7ffe0fe5158f
obj_:0x7ffe0fe5158f objaaa 0x7ffe0fe5158f
Print A 0x7ffe0fe5158f
my machine: Linux x86-64, gcc 4.8
In my opinion, "Object obj2(a2);" makes a class Model by lvalue reference, so it should call A's copy constructor,
but actually it did not work, it makes me confused.
someone can give a explanation, thank you in advance.
the program is list as follow:
#include <memory>
#include <iostream>
class Object {
public:
template <typename T>
Object(T&& obj) : object_(std::make_shared<Model<T>>(std::forward<T>(obj))) {
}
void PrintName() {
object_->PrintName();
}
private:
class Concept {
public:
virtual void PrintName() = 0;
};
template <typename T>
class Model : public Concept {
public:
Model(T&& obj) : obj_(std::forward<T>(obj)) {
std::cout << "obj_:" << std::addressof(obj_) <<" objaaa " << std::addressof(obj) << std::endl;
}
void PrintName() {
obj_.PrintName();
}
private:
T obj_;
};
private:
std::shared_ptr<Concept> object_;
};
class A {
public:
A(A& a) {
std::cout<< "A copy cstr...a" << this << std::endl;
}
A(A&& a) {
std::cout << "A move cstr...." <<this<< std::endl;
}
A() {
std::cout << "A default cstr..." <<this<< std::endl;
}
void PrintName() {
std::cout << "Print A " << this << std::endl;
}
};
int main(void)
{
// test case 1
Object obj{A()};
obj.PrintName();
// test case 2
A a2;
Object obj2(a2);
obj2.PrintName();
return 0;
}

Answer 1

In Object obj2(a2);, no copy is made. T in the constructor of Object is deduced to be A&, so it instantiates Model<A&>, which stores a reference to the original a2 object as its obj_ member.
Observe that in your debug output, a2's constructor, Model's constructor and PrintName all print the same address. You can further confirm that this address is in fact &a2.