Description:
------------
When overriden, calling the constructor of class Exception 
ignores the default arguments, if the properties $code and 
$message are already set.

From looking at the implementation of the constructor[1], 
the behavior is to be expected, because when the default 
values are passed for $code and $message, zend_update_property_*()
is not called.

I am fully aware that the given test script shows a bad 
programming practise, but it would work for user defined 
classes, and the unusual behavior of the Exception constructor 
doesn't seem to be documented.  At least this should be done, IMHO.

[1] <http://lxr.php.net/xref/PHP_5_5/Zend/zend_exceptions.c#223>

Test script:
---------------
// cf. <http://3v4l.org/3Ylvi#v430>

class MyException extends Exception
{
    function __construct()
    {
        $this->code = 42;
        $this->message = "foo";
        parent::__construct();
    }
}

try {
    throw new MyException();
} catch (MyException $e) {
    var_dump($e->getCode());
    var_dump($e->getMessage());
}


Expected result:
----------------
int(0)
string(0) ""

Actual result:
--------------
int(42)
string(3) "foo"