$ php-5.6.3 6-parent.php 
C::C
 A::__construct
B::B
PHP Fatal error:  Call to undefined method B::A() in /home/cweiske/Dev/pear/test/165/6-parent.php on line 15

Fatal error: Call to undefined method B::A() in /home/cweiske/Dev/pear/test/165/6-parent.php on line 15