using System;

public class Program

{

    static void foo_check(int inner) { }

    static void foo_check(float inner) { }

    static void foo_check(long inner) { }

​

    static void foo<T>(T outer) where T: struct, 

          IComparable, 

          IComparable<T>, 

          IConvertible, 

          IEquatable<T>, 

          IFormattable

    {

        foo_check(outer as dynamic);

        Console.WriteLine(outer);

    }

    public static void Main()

    {

        Console.WriteLine("Hello World");

        foo(123);

        foo(123.45f);

    }

}