Why ref and out are not sufficient to disambiguate overloaded in C#?

Question

For example, why this method Max(ref int x, ref int y) is not considered overload of Max(int x, int y)? Why is the same with out?

Answer 1

Let's write some code:

static void M1(int y)
{
    Console.WriteLine("val");
}

static void M1(ref int y)
{
    Console.WriteLine("ref");
}

//static void M1(out int y)  // compile error
//{
//    Console.WriteLine("out");
//}

static void Main2()
{
    int a = 3;

    M1(a);
    M1(ref a);
//    M1(out a);

}

Ther only is a conflict between the ref and out versions. Comment out the out parameter method and it compiles and runs as expected: Output is val and ref .