using System;

using System.Reflection.Emit;

​

public class Program

{

    int Size(Type type)

    {

        var dynamicMethod = new DynamicMethod("SizeOf", typeof (int), Type.EmptyTypes);

        var generator = dynamicMethod.GetILGenerator();

        generator.Emit(OpCodes.Sizeof, type);

        generator.Emit(OpCodes.Ret);

        var function = (Func<int>)dynamicMethod.CreateDelegate(typeof (Func<int>));

        return function();

    }

​

    public void Main()

    {

        Size(typeof (S<G<A>>)).Dump();

        System.Runtime.InteropServices.Marshal.SizeOf(default (S<G<A>>)).Dump();

    }

​

    struct S<T>

    {

        T Value;

    }

    class G<T> 

    {

        public int X;

    }

​

    struct A

    {

        int X;

        int Y;

        int Z;

    }

}