using System;

using System.Runtime.CompilerServices;

public class Program

{   

    static string Stringify(object obj, [CallerArgumentExpression("obj")] string expr = "")

    {

        return expr;

    }

    public class Foo {

        public string Bar = "bar";

    }

    public static Foo FooSingleton = new();

    public static void Main()

    {

        var expr = Stringify(FooSingleton.Bar);

        Console.WriteLine(expr); // prints "FooSingleton.Bar"

        expr = Stringify(FooSingleton.Bar + FooSingleton.Bar);

        Console.WriteLine(expr); // prints "FooSingleton.Bar + FooSingleton.Bar"

    }

}