1. K. Rustan M. Leino RiSE, Microsoft Research Typing, Analysis and Verification of Heap-Manipulating Programs Dagstuhl, Germany 20 July 2009

2. Invariants Describes what holds of an object in its steady state When does an invariant hold? Frames Describes what is being modified or read Goals: Flexibility Conciseness

3. Ownership Various type systems JML Spec# Dynamic frames Kassios VeriCool Dafny Permissions, capabilities Boyland et al. Separation logic Chalice

4. .gigs.gt.gigs.gt.Level.Level Play() Strum() r g :RockBand :Guitar Invariants: 0 ≤ gigs 7 ≤ gt.Level Invariants: 0 ≤ gigs 7 ≤ gt.Level

5. Object invariant declarations Object state: Mutable Valid Consistent Committed Ownership System of owners, rep objects, and peers Enforced in logic modifies clauses say what fields of mutable and consistent objects are modified :Rock Band :Guitar:Guitar :GtString:GtString:GtString:GtString mutable consistent committed

6. Sets Functions Ghost state Style of specification Valid() – describes steady state footprint – set of objects in the aggregate (cf. valid/state paradigm in ESC/Modula-3)

7. Permissions guide what can be read and written Predicates and functions Valid *) language designed for concurrency

8. Spec# + Intuitive declarations naturally capture common situations; Readonly, frozen - Hard to break out of methodology Dafny + Simple language; Flexible - Verbose; Extension to concurrency? Chalice + Flexible - Simulatenous, different abstraction levels?; Mental overhead

9. Dafny, Chalice, Boogie available as open source: http://boogie.codeplex.com http://boogie.codeplex.com Spec# available in binary form: http://research.microsoft.com/specsharp http://research.microsoft.com/specsharp and soon also available as open source under academic license: http://specsharp.codeplex.com http://specsharp.codeplex.com

10. Spec# Vision paper (CASSIS), 2004 Spec# methodology (nee Boogie methodology), 2004 ff. Retrospective paper, 2009 Dafny Model and tutorial (Marktoberdorf), 2008 Chalice Model (ESOP), 2009 Tutorial (FOSAD), 2009 Boogie Boogie 1 architecture paper (FMCO), 2005 Boogie 2 type system and logic, 2009 Boogie 2 language reference manual, 2008 http://research.microsoft.com/~leino/papers.html

11. Spec#Spec# C with HAVOC specifications DafnyDafny C with VCC specifications ChaliceChalice Z3Z3SimplifySimplify SMT Lib BoogieBoogie Isabelle/ HOL