Silicon implementation of new backend-independent counterexample format

src/main/resources/z3config.smt2

@@ -25,6 +25,7 @@
 (set-option :smt.qi.eager_threshold 100)
 (set-option :smt.arith.solver 2)
 (set-option :model.v2 true)
+(set-option :model.partial true)
 
 ; We want unlimited multipatterns
 (set-option :smt.qi.max_multi_patterns 1000)

src/main/scala/rules/SymbolicExecutionRules.scala

@@ -8,11 +8,12 @@ package viper.silicon.rules
 
 import viper.silicon.debugger.DebugExp
 import viper.silicon.interfaces.{Failure, SiliconDebuggingFailureContext, SiliconFailureContext, SiliconMappedCounterexample, SiliconNativeCounterexample, SiliconVariableCounterexample}
+import viper.silicon.reporting.SiliconExtendedCounterexample
 import viper.silicon.state.State
 import viper.silicon.state.terms.{False, Term}
 import viper.silicon.verifier.Verifier
+import viper.silver.frontend.{ExtendedModel, IntermediateModel, MappedModel, NativeModel, VariablesModel}
 import viper.silver.ast
-import viper.silver.frontend.{MappedModel, NativeModel, VariablesModel}
 import viper.silver.verifier.errors.ErrorWrapperWithExampleTransformer
 import viper.silver.verifier.{Counterexample, CounterexampleTransformer, VerificationError}
 
@@ -69,6 +70,8 @@ trait SymbolicExecutionRules {
             SiliconVariableCounterexample(s.g, nativeModel)
           case MappedModel =>
             SiliconMappedCounterexample(s.g, s.h.values, s.oldHeaps, nativeModel, s.program)
+          case IntermediateModel => SiliconExtendedCounterexample(nativeModel, s.g, s.h.values, s.oldHeaps, s.program).imCE
+          case ExtendedModel => SiliconExtendedCounterexample(nativeModel, s.g, s.h.values, s.oldHeaps, s.program)
         }
         val finalCE = ceTrafo match {
           case Some(trafo) => trafo.f(ce)

src/test/scala/GeneralCounterexampleTests.scala

@@ -0,0 +1,26 @@
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+//
+// Copyright (c) 2011-2025 ETH Zurich.
+
+package viper.silicon.tests
+
+import viper.silicon.Silicon
+import viper.silver.testing.{CounterexampleTestInput, DefaultAnnotatedTestInput}
+
+import java.nio.file.Path
+
+class GeneralCounterexampleTests extends SiliconTests {
+  override val testDirectories: Seq[String] = Seq("counterexample_mapped", "counterexample_general")
+
+  override def configureVerifiersFromConfigMap(configMap: Map[String, Any]): Unit = {
+    val args = Silicon.optionsFromScalaTestConfigMap(prefixSpecificConfigMap(configMap).getOrElse("silicon", Map()))
+    val additionalArgs = Seq("--counterexample", "extended")
+
+    silicon.parseCommandLine(args ++ additionalArgs :+ Silicon.dummyInputFilename)
+  }
+
+  override def buildTestInput(file: Path, prefix: String): DefaultAnnotatedTestInput =
+    CounterexampleTestInput(file, prefix)
+}

src/test/scala/CounterexampleTests.scala → src/test/scala/MappedCounterexampleTests.scala

@@ -17,8 +17,8 @@ import viper.silver.verifier.{FailureContext, VerificationError}
 
 import java.nio.file.Path
 
-class CounterexampleTests extends SiliconTests {
-  override val testDirectories: Seq[String] = Seq("counterexamples")
+class MappedCounterexampleTests extends SiliconTests {
+  override val testDirectories: Seq[String] = Seq("counterexample_mapped")
 
   override def configureVerifiersFromConfigMap(configMap: Map[String, Any]): Unit = {
     val args = Silicon.optionsFromScalaTestConfigMap(prefixSpecificConfigMap(configMap).getOrElse("silicon", Map()))
@@ -53,7 +53,7 @@ class CounterexampleTests extends SiliconTests {
     override val outputIdPattern: String = "([^:]*)(:([^,]*))?"
 
     private def isExpectedCounterexample(annotation: String, file: Path, lineNr: Int): Option[TestAnnotation] = {
-      def parseExpectedCounterexample(id: OutputAnnotationId, expectedCounterexampleString: String): Option[ExpectedCounterexampleAnnotation] = {
+      def parseExpectedCounterexample(id: OutputAnnotationId, expectedCounterexampleString: String): Option[ExpectedMappedCounterexampleAnnotation] = {
         // in order to reuse as much of the existing Viper parser as possible, we have to initialize the `_file` and `_line_offset` fields:
         val fp = new FastParser()
         fp._file = file.toAbsolutePath
@@ -68,7 +68,7 @@ class CounterexampleTests extends SiliconTests {
         val cParser = new CounterexampleParser(fp)
         // now parsing is actually possible:
         fastparse.parse(expectedCounterexampleString, cParser.expectedCounterexample(_)) match {
-          case Parsed.Success(expectedCounterexample, _) => Some(ExpectedCounterexampleAnnotation(id, file, lineNr, expectedCounterexample))
+          case Parsed.Success(expectedCounterexample, _) => Some(ExpectedMappedCounterexampleAnnotation(id, file, lineNr, expectedCounterexample))
           case Parsed.Failure(_, _, extra) =>
             println(s"Parsing expected counterexample failed in file $file: ${extra.trace().longAggregateMsg}")
             None
@@ -88,7 +88,7 @@ class CounterexampleTests extends SiliconTests {
 }
 
 /** represents an expected output (identified by `id`) with an associated (possibly partial) counterexample model */
-case class ExpectedCounterexampleAnnotation(id: OutputAnnotationId, file: Path, forLineNr: Int, expectedCounterexample: ExpectedCounterexample) extends CustomAnnotation {
+case class ExpectedMappedCounterexampleAnnotation(id: OutputAnnotationId, file: Path, forLineNr: Int, expectedCounterexample: ExpectedCounterexample) extends CustomAnnotation {
   override def matches(actual: AbstractOutput): Boolean =
     id.matches(actual.fullId) && actual.isSameLine(file, forLineNr) && containsModel(actual)
 
@@ -164,5 +164,5 @@ case class ExpectedCounterexampleAnnotation(id: OutputAnnotationId, file: Path,
 
   override def notFoundError: TestError = TestCustomError(s"Expected the following counterexample on line $forLineNr: $expectedCounterexample")
 
-  override def withForLineNr(line: Int = forLineNr): ExpectedCounterexampleAnnotation = ExpectedCounterexampleAnnotation(id, file, line, expectedCounterexample)
+  override def withForLineNr(line: Int = forLineNr): ExpectedMappedCounterexampleAnnotation = ExpectedMappedCounterexampleAnnotation(id, file, line, expectedCounterexample)
 }