title: Accessing parent with late static binding
body: <p>I'd like to be able to get the late static binded class's parent.  I've written a non-functioning code example to clarify what I mean:</p>
  
  <pre><code>class A
  {
      public static function getCombinedProperties()
      {
          $a = static::$properties; // Late static binding means this will work
          if(isset(static::parent::$properties))  // Calling static::parent obviously does not work
              $a = array_merge_recursive($a, static::parent::$properties);
          return $a;
      }
  }
  
  class B extends A
  {
      public static $properties = ['fruits' =&gt; ['pineapple', 'mango']];
  }
  
  class C extends B
  {
      public static $properties = ['fruits' =&gt; ['apple', 'banana'], 'vegetables' =&gt; ['carrot', 'pea']];
  }
  
  B::getCombinedProperties(); //desired output ['fruits' =&gt; ['pineapple', 'mango']]
  C::getCombinedProperties(); //desired output ['fruits' =&gt; ['apple', 'banana', 'pineapple', 'mango'], 'vegetables' =&gt; ['carrot', 'pea']]
  </code></pre>
  
  <p>Is it possible for class A get access to the $properties attribute of class B when the method is called from class C?</p>