Alloy as a Refactoring Checker?

Refactorings are systematic changes made to programs, models or specifications in order to improve their structure without changing the externally observable behaviour. We will examine how a constraint solver (the Alloy Analyzer) can be used to automatically check if refactorings, applied to a formal specification (written in Z), meet this requirement. Furthermore, we identify a class of refactorings for which the use of this tool is reasonable in general.