title: PHP's static member and instance member seems no different. Why PHP does so(Without warning)?
body: <pre><code>&lt;?php
  class A {
    public function instanceFunc() {
      echo "instance";
    }
  
    public static function staticFunc() {
      echo "static";
    }
  }
  
  A::instanceFunc(); // instance
  $a = new A();
  $a-&gt;staticFunc(); // static
  </code></pre>
  
  <p>This means in PHP static method and instance method have no different at all.
  Zend doesn't even complain about it(WITHOUT WARNING).</p>
  
  <p>In Zend Engine. both static method and instance method all saved in zend_class_entry.function_table.</p>
  
  <p>Why PHP behave like this? It's a bug or feature?</p>