Struct inheritance test program in C# (related article on http://xoofx.com/blog/2015/09/27/struct-inheritance-in-csharp-with-roslyn-and-coreclr/)

HelloWorld.cs

using System;

public struct ValueBase
{
    public int A;

    public int B;

    public int Calculate()
    {
        return this.A + this.B;
    }
}

public struct ValueDerived : ValueBase
{
    public int C;

    public new int Calculate()
    {
        return base.Calculate() + C;
    }
}

public class Program
{
    public static int StaticCalculateByRefBase(ref ValueBase value)
    {
        return value.A + value.B;
    }

    public static int StaticCalculateOnBase(ValueBase value)
    {
        return value.A + value.B;
    }

    static void Assert(string context, int value, int expected)
    {
        Console.WriteLine(context + " = {0}, expect = {1}, {2}", value, expected, value == expected ? "Ok" : "Error");
    }

    public unsafe static void Main(string[] args)
    {
        var valueDerived = new ValueDerived();
        // Object initializer is not supported in this example, so we initialize fields directly
        valueDerived.A = 1;
        valueDerived.B = 3;
        valueDerived.C = 5;

        // Check memory layout.
        var ptr = (int*)&valueDerived;
        Assert("valueDerived.A", valueDerived.A, ptr[0]);
        Assert("valueDerived.B", valueDerived.B, ptr[1]);
        Assert("valueDerived.C", valueDerived.C, ptr[2]);

        // Call the Calculate method on derived struct
        Assert("valueDerived.Calculate()", valueDerived.Calculate(), 1 + 3 + 5);

        // Call the Calculate method on base struct
        var valueBase = (ValueBase)valueDerived;
        Assert("valueBase.Calculate()", valueBase.Calculate(), 1 + 3);

        // Call a static method with by ref to base type
        var result1 = StaticCalculateByRefBase(ref valueDerived);
        Assert("StaticCalculateByRefBase(ref valueDerived)", result1, 1 + 3);

        // Call a static method with cast to base type (no cast will generate an error)
        var result2 = StaticCalculateOnBase((ValueBase)valueDerived);
        Assert("StaticCalculateOnBase((ValueBase)valueDerived)", result2, 1 + 3);
    }
}