#include <iostream>
#include <type_traits>
using namespace std;
 
class MyClass
{
	public:
	int a = 1;
};
 
class Derived : public MyClass
{
	public:
	int b = 2;
};
 
class NotDerived
{
	public:
	int b = 3;
};
 
template<typename T, typename std::enable_if<std::is_base_of<MyClass, T>::value>::type* = nullptr>
    T Foo(T bar)
    {
       return T();
    }
 
int main() {
	Derived d;
	NotDerived nd;
	std::cout << Foo(d).b << std::endl;; // works
	//std::cout << (Foo(nd)).b << std::endl;; //compiler error
 
	return 0;
}

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