Sorry, but the bug system is not the appropriate forum for asking
support questions. Your problem does not imply a bug in PHP itself.
For a list of more appropriate places to ask for help using PHP,
please visit http://www.php.net/support.php

Thank you for your interest in PHP.

It's a FEATURE REQUEST, not a support question.

Currently, PHP's error message when encountering:

class foo {

the SECOND time simply tells me it's "already defined".

While that would be useful if I was, say, including the same 
file twice, it's not particularly  useful when trying to 
integrate two (or more) object-oriented 3rd-party libraries.

The error message would be infinitely more useful if it 
included the __FILE__ and __LINE__ of the first:
class foo {

This is essentially the same problem/solution as the old 
"headers already sent" problem, which now explicitly states 
which line/file caused the original out

The engine can't always guarantee to be able to know
exactly where the class was defined.
For instance, the class might be an internal class (like
the Directory class) defined by an extension, or it might have been generated by an eval statement.

The definition location should be fairly easy to
store/recall - just add a field to zend_class_entry,
and tweak the parser so that the error message is more
meaningful.  I'll forward this on to some other developers
and we'll see what comes up.

Until this is implemented, you can use something like
this from your unix/cygwin shell prompt:
grep -ni 'class User' $(find -name '*.php')

The Reflection API in PHP5 can tell you where a class was defined. 

See http://www.sitten-polizei.de/php/reflection_api/docs/language.reflection.class.reflection_class.html for details.

So, with the Reflection API this is possible -> closing