Description:
------------
Normally you can declare classes in any order inside of a php file. When one of your classes implements an interface, php will throw a fatal error about class not found if the class is declared in the wrong order.

If you remove the implements clause then order does not matter.

php bug http://bugs.php.net/bug.php?id=39758 also shows this and the reply from dmitry was:

PHP always declares classes those implement interfaces at run-time. So in your example you cannot declare "Bar" because "Foo" is not declared yet.
Your report may be categorised as "feature request", but it cannot be fixed in 5.2.* anyway, because of binary compatibility.


Just because the internals handle things in a certain order does not mean that php should exhibit contradicting behavior based on valid class definitions.

Test script:
---------------
test.php
<?php
class One extends Two {}
interface Three {}
class Two implements Three {}
?>

test2.php
<?php
class One extends Two {}
interface Three {}
class Two {}
?>

Expected result:
----------------
test.php:
no output

test2.php:
no output

Actual result:
--------------
jjohnston:~$ php test.php 
PHP Fatal error:  Class 'Two' not found in /Users/jjohnston/test.php on line 2

Fatal error: Class 'Two' not found in /Users/jjohnston/test.php on line 2

jjohnston:~$ php test2.php