<?php
class A {
  public $foo = 'abc';
}
class B extends A {
  public $foo = 'cde';
  public function bar() {
    echo $this->foo;
    echo parent::$foo;
  }
}
$b = new B;
$b->bar();

cde
Fatal error: Access to undeclared static property:  A::$foo on line 9