Description:
------------
Using PHP Version 5.5.8 on macOSX 10.8.5

PCRE Library Version 8.33 2013-05-28


I may be wrong,
but I think there is a problem with the PCRE implementation in php.

The php test is here: http://ideone.com/NuORid
The perl equivalent test is here: http://ideone.com/RGHaLK


Now, I know perl and pcre are two different flavours, but in this case,
I was expecting the same behaviour.


About the php test:
I tried to use a condition on a recursion (which is supposed to always fail at the top level).
The condition has two alternatives: the yes condition and the no condition.
In the subject, there is no recursion at all, so the second alternative should be used,
and the first alternative ignored.

It seems that the pattern match only if the first alternative doesn't use a duplicate named subpattern,
or, alternatively, if a backreference to the named subpattern uses the numbered version of the
subpattern (and not the name).

Test script:
---------------
http://ideone.com/NuORid

Expected result:
----------------
The script http://ideone.com/NuORid should output "ok"

Actual result:
--------------
The script http://ideone.com/NuORid outputs "oops"