Refactoring, one of XP core practices, aims at keeping the software design simple and flexible. It assumes changing internal structure of the code without influencing its functionality [1]. However, since refactoring is a costly and complex process, researchers and practitioners try to automate or semi-automate it (e.g. [2]), having in mind both decreasing the cost and preventing it from introducing new errors to the code. The automation is usually based on syntactic verification of well-known conditions that must be met to successfully apply a given transformation. Unfortunately, only a few among refactorings catalogued by Martin [4] are subject to full automation.