Code snippet for the blog post https://sriramsakthivel.wordpress.com/2014/12/27/breaking-the-clr-type-safety/

breaking-the-clr-type-safety.cs

[StructLayout(LayoutKind.Explicit)]
public struct Union
{
    [FieldOffset(0)]
    public StringBuilder Builder;
 
    [FieldOffset(0)]
    public string Text;
}
 
internal class Program
{
    private static void Main(string[] args)
    {
        Union union = new Union
        {
            Builder = new StringBuilder()
        };
 
        //text is not a string, it is StringBuilder. What the heck??
        string text = union.Text;
 
        //Prints some number, when I run it happens to be 25306168
        Console.WriteLine(text.Length);
 
        //GetType() returns System.Text.StringBuilder correctly because .net
        //stores metadata about object in itself.
        Console.WriteLine(text.GetType());
 
        Console.ReadLine();
    }
}