<?php  class A {     protected function pro()     {         return "pro";     }      public function pub()     {         return "pub";     } }  $a = new A(); $ext = function () {     var_dump($this);     // var_dump($this->pro()); //Error: Call to protected method A::pro()      var_dump($this->pub()); }; $ext = $ext->bindTo($a);  var_dump($ext());