A unified framework for verification techniques for object invariants — ecoop’08 full paper. Available from http://www.doc.ic.ac.uk/∼ajs300m/papers/ frameworkFull.pdf

Abstract. Object invariants define the consistency of objects. They have subtle semantics because of call-backs, multi-object invariants and subclassing. Several visible-state verification techniques for object in-variants have been proposed. It is difficult to compare these techniques and ascertain their soundness because of differences in restrictions on programs and invariants, in the use of advanced type systems (e.g., own-ership types), in the meaning of invariants, and in proof obligations. We develop a unified framework for such techniques. We distil seven pa-rameters that characterise a verification technique, and identify sufficient conditions on these parameters which guarantee soundness. We instanti-ate our framework with three verification techniques from the literature, and use it to assess soundness and compare expressiveness.