Why Universal Reference concept not working for map insert in case of function pointers

Question

Can someone explain why below piece of code is not working if I don't use explicitly std::pair with map insert :

#include <iostream>
#include <string>
#include <map>
#include <memory>
typedef std::shared_ptr<int>(*CreatorFunction)();
std::shared_ptr<int> test()
{
    std::shared_ptr<int> p(new int);
    return p;
}
int main()
{
  std::map<int, CreatorFunction> tmap; 
  tmap.insert(1,test); //this doesn't work
  tmap.insert(std::pair<int,CreatorFunction>(1,test)); //this works
 return 0;
}

My understanding is in c++14 we don't need to use std::pair as insert function definition is changed to accept universal reference as indicated below :

template <class P> pair<iterator,bool> insert (P&& val);

Answer 1

There is no any overload in std::map::insert that takes two arguments you should use std::make_pair. See the snippet below

#include <iostream>
#include <string>
#include <map>
#include <memory>

#include <functional> // for std::function.

// typedef std::shared_ptr<int>(*CreatorFunction)();
typedef std::function<std::shared_ptr<int>()> CreatorFunction; // The c++ way.

// Take a look at this function. std::shared_ptr<int> will automatically destroy the int* and might result in undefined.
std::shared_ptr<int> test()
{
    std::shared_ptr<int> p(new int);
    return p;
}
int main()
{
    std::map<int, CreatorFunction> tmap; 
    tmap.insert(std::make_pair(1,test)); // edited this line
    tmap.insert(std::pair<int,CreatorFunction>(1,test)); // this works
    return 0;
}