Description:
------------
I just have seen this commit:

http://git.php.net/?p=php-src.git;a=commitdiff;h=8991ed016fa257c9f8ba42580c34568b3c2ce3e5

Could you also add $instance->class ?
Which operates on an already instanced Object. Would be for example useful to be able to handle internal and userland classes differently.

Test script:
---------------
function isInternalObject ($object) {
	if (!is_object($object))
		return false;
	return !file_exists("classes/$object.php");
}

// In the case where you name the files with the name of their class...

include 'classes/Foo.php';

$foo = new Foo();
$std = new stdClass;

var_dump(isInternalObject($foo));
var_dump(isInternalObject($std));

Expected result:
----------------
bool(false)
bool(true)

Actual result:
--------------
Notice: Undefined property: %s::$class in php shell code on line 1