Deduce return type through decltype

gistfile1.cpp

// compiles with gcc 4.7+:
// g++ -Wall -W -g -std=c++11 test.cpp -o /tmp/test
//
// ... and clang 3.0+:
// clang++ -W -g -std=c++11 test.cpp -o /tmp/test
#include <iostream>
#include <typeinfo>

template<class T, class U>
auto mul(T x, U y) -> decltype(x*y)
{
    return x*y;
}

int
main()
{
    auto result1 = mul(1.5, 2);
    std::cout << typeid(result1).name() << ": " << result1 << std::endl;

    auto result2 = mul(3, 2);
    std::cout << typeid(result2).name() << ": " << result2 << std::endl;

    auto result3 = mul(1.5f, 2);
    std::cout << typeid(result3).name() << ": " << result3 << std::endl;

    return 0;
}