Merge pull request #774 from viperproject/meilers_fix_773

Fixing issue #773

Author: marcoeilers

src/main/scala/rules/Executor.scala

@@ -253,13 +253,8 @@ object executor extends ExecutionRules {
                   phase1data = phase1data :+ (s1,
                                               v1.decider.pcs.after(mark),
                                               v1.decider.freshFunctions /* [BRANCH-PARALLELISATION] */)
-                  v1.decider.prover.comment("Loop head block: Check well-definedness of edge conditions")
-                  edgeConditions.foldLeft(Success(): VerificationResult) {
-                    case (result, _) if !result.continueVerification => result
-                    case (intermediateResult, eCond) =>
-                      intermediateResult combine executionFlowController.locally(s1, v1)((s2, v2) => {
-                        eval(s2, eCond, WhileFailed(eCond), v2)((_, _, _) =>
-                          Success())})}})})
+                  Success()
+                })})
             combine executionFlowController.locally(s, v)((s0, v0) => {
                 v0.decider.prover.comment("Loop head block: Establish invariant")
                 consumes(s0, invs, LoopInvariantNotEstablished, v0)((sLeftover, _, v1) => {
@@ -276,8 +271,19 @@ object executor extends ExecutionRules {
                           Success()
                         else {
                           execs(s3, stmts, v2)((s4, v3) => {
+                            val edgeCondWelldefinedness = {
+                              v1.decider.prover.comment("Loop head block: Check well-definedness of edge conditions")
+                              edgeConditions.foldLeft(Success(): VerificationResult) {
+                                case (result, _) if !result.continueVerification => result
+                                case (intermediateResult, eCond) =>
+                                  intermediateResult combine executionFlowController.locally(s4, v3)((s5, v4) => {
+                                    eval(s5, eCond, WhileFailed(eCond), v4)((_, _, _) =>
+                                      Success())
+                                  })
+                              }
+                            }
                             v3.decider.prover.comment("Loop head block: Follow loop-internal edges")
-                            follows(s4, sortedEdges, WhileFailed, v3, joinPoint)(Q)})}})}})}))
+                            edgeCondWelldefinedness combine follows(s4, sortedEdges, WhileFailed, v3, joinPoint)(Q)})}})}})}))
 
           case _ =>
             /* We've reached a loop head block via an edge other than an in-edge: a normal edge or