`PHPCompatibility` does not resolve namespaced class name or function name. For example,
```lang=php,name=test.php
use MyNamespace\CURLFile;
new CURLFile();
```
```
$ arc lint test.php
Error (XHP45) PHP Compatibility
This codebase targets PHP 5.2.3, but `CURLFile` was not introduced until
PHP 5.5.0.
2
3 use MyNamespace\CURLFile;
4
>>> 5 new CURLFile();
```
Clearly the code is using `\MyNamespace\CURLFile` instead of `\CURLFIle`.