title: PHP override error
body: <p>I'm trying to override a method but I get an error, that the function could not be found.
  Here's an example:</p>
  
  <pre><code>abstract class a {
      public function build(){
          $this._loadComponents();
          return $this;
      }
  
      abstract protected function _loadComponents();
  }
  
  class b extends a {
      protected function _loadComponents(){
          echo "test";
      }
  }
  $b = new B();
  $b-&gt;build();
  </code></pre>
  
  <p>Results in: Fatal error: Call to undefined function</p>
  
  <p>What am I doing wrong?</p>