title: Automapper unexpected behaviour with map between inherited types
body: <p>I have the following situation (C#):</p>
  
  <pre><code>public class A: B
  {
        public ComplexType MyCT {get;set;}
  
  }
  
  public class B: 
  {
        public string MyString {get;set;}
  
  }
  </code></pre>
  
  <p>I have an instance of A and I want to use Automapper to map it to an instance of B as after the mapping I do not need "MyCT" (this is a cut down version obviously).</p>
  
  <pre><code>B myB = Mapper.Map&lt;A, B&gt;(myA);
  </code></pre>
  
  <p>but when I try to do something with myB (I'm saving it into Azure which can't handle my complex type, hence trying to throw it away if you like) an exception is thrown telling my that MyCT is still hanging around the myB object.</p>
  
  <p>When I debug I can cast it to A and sure enough I have access to MyCT.</p>
  
  <p>What am missing, I feel like I'm fundamentally missing something here presumably to do with the inheritance between the two types.</p>