Description:
------------
The following behaviour seems incorrect.

PHP founds the abstract class if it doesn't implement an interface, but doen't found it if it implements an interface.

Reproduce code:
---------------
<?php

interface MyInterface { }

class MyClass extends MyAbstractClass { }

abstract class MyAbstractClass implements MyInterface { }

?>

<?php

interface MyInterface { }

class MyClass extends MyAbstractClass implements MyInterface { }

abstract class MyAbstractClass { }

?>

Expected result:
----------------
First :
- Should work

Second :
- Should work

Actual result:
--------------
First :

Fatal error: Class 'MyAbstractClass' not found in /www/test.php on line 5

Second :
- Work