title: How to force classes derived from an abstract class to implement GetHashCode
body: <p>I have a base class</p>
  
  <pre><code>public abstract class MyBaseClass()
  {
      // ...
  }
  </code></pre>
  
  <p>and I want to ensure that derived classes implement their own custom <code>GetHashCode</code> method. Is</p>
  
  <pre><code>public abstract class MyBaseClass()
  {
      // ...
  
      public abstract override int GetHashCode();
  }
  </code></pre>
  
  <p>the way to do it, or is the entire idea code smell?</p>