using System;

​

X a = new(3), b = new(2);

X c = a + b;

Console.Write(c);

​

class X

{

    int Val{ get; init; }

    public X (int val) { Val = val; }

    /*public*/ static X operator+(X x0, X x1) => new(x0.Val + x1.Val);

    public override string ToString() => $"{Val}";

}

​