Is that really?
I tested it.
```
> php -v
PHP 5.4.13 (cli) (built: Mar 15 2013 02:07:14)
Copyright (c) 1997-2013 The PHP Group
Zend Engine v2.4.0, Copyright (c) 1998-2013 Zend Technologies
    with Xdebug v2.2.2, Copyright (c) 2002-2013, by Derick Rethans

```
```php
<?php
var_dump((false instanceof \StdClass));

```
raises
PHP Fatal error:  instanceof expects an object instance, constant given in - on line 2

Please try it.