Description:
------------
When creating a datetime object from a string that includes timezone offset information (like "10:00:00+02:00"), the timezone object's name can not be used for creating new timezone objects or setting the default timezone. In effect, it's an "impossible object": there's no way to recreate an object like that yourself.

This also means you would get unexpected results when using, for example, strftime(). If you use date_default_timezone_set to change the timezone to the object's timezone and print the date info, it will give you the wrong output.

Reproduce code:
---------------
<?php
date_default_timezone_set('UTC');
echo "Before: ".date_default_timezone_get()."\n";
$foo = new datetime('10:00:00+02:00');
$name = $foo->getTimeZone()->getName();
echo "Setting timezone: $name\n";
date_default_timezone_set($name);
echo "After: ".date_default_timezone_get()."\n";
echo "strftime: ".strftime('%H:%M:%S', $foo->format('U'))."\n";

$bar = new datetimezone($name);
echo "datetimezone object name: ".$bar->getName();
?>

Expected result:
----------------
Before: UTC
Setting timezone: GMT+02
After: GMT+02
strftime: 10:00:00
datetimezone object name: GMT+02

(not sure if GMT+02 is the correct timezone name. In any case, it should be some timezone name that's accepted by other timezone-related functions/classes)

Actual result:
--------------
Before: UTC
Setting timezone: +02:00
After: UTC
strftime: 08:00:00

PHP Fatal error:  Uncaught exception 'Exception' with message 'DateTimeZone::__construct(): Unknown or bad timezone (+02:00)' in /path/to/index.php:10