IDEA-188554 Infer method return value immutability from source

java/java-analysis-impl/src/com/intellij/codeInsight/InferredAnnotationsManagerImpl.java

@@ -21,7 +21,8 @@ import static com.intellij.codeInspection.dataFlow.ControlFlowAnalyzer.ORG_JETBR
 
 public class InferredAnnotationsManagerImpl extends InferredAnnotationsManager {
   private static final Set<String> INFERRED_ANNOTATIONS =
-    ContainerUtil.set(NOT_NULL, NULLABLE, ORG_JETBRAINS_ANNOTATIONS_CONTRACT);
+    ContainerUtil.set(NOT_NULL, NULLABLE, ORG_JETBRAINS_ANNOTATIONS_CONTRACT, Mutability.UNMODIFIABLE_ANNOTATION,
+                      Mutability.UNMODIFIABLE_VIEW_ANNOTATION);
   private final Project myProject;
 
   public InferredAnnotationsManagerImpl(Project project) {
@@ -64,6 +65,10 @@ public class InferredAnnotationsManagerImpl extends InferredAnnotationsManager {
       return anno == null ? null : annotationFQN.equals(anno.getQualifiedName()) ? anno : null;
     }
 
+    if (Mutability.UNMODIFIABLE_ANNOTATION.equals(annotationFQN) || Mutability.UNMODIFIABLE_VIEW_ANNOTATION.equals(annotationFQN)) {
+      return getInferredMutabilityAnnotation(listOwner);
+    }
+
     if (listOwner instanceof PsiMethodImpl && ORG_JETBRAINS_ANNOTATIONS_CONTRACT.equals(annotationFQN)) {
       return getInferredContractAnnotation((PsiMethodImpl)listOwner);
     }
@@ -97,6 +102,17 @@ public class InferredAnnotationsManagerImpl extends InferredAnnotationsManager {
     return false;
   }
 
+  @Nullable
+  private PsiAnnotation getInferredMutabilityAnnotation(@NotNull PsiModifierListOwner owner) {
+    if (!(owner instanceof PsiMethod)) return null;
+    PsiModifierList modifiers = ((PsiMethod)owner).getModifierList();
+    if (modifiers.findAnnotation(Mutability.UNMODIFIABLE_ANNOTATION) != null ||
+        modifiers.findAnnotation(Mutability.UNMODIFIABLE_VIEW_ANNOTATION) != null) {
+      return null;
+    }
+    return Mutability.inferMutability(owner).asAnnotation(myProject);
+  }
+
   @Nullable
   private PsiAnnotation getInferredContractAnnotation(PsiMethodImpl method) {
     if (method.getModifierList().findAnnotation(ORG_JETBRAINS_ANNOTATIONS_CONTRACT) != null) {
@@ -214,6 +230,8 @@ public class InferredAnnotationsManagerImpl extends InferredAnnotationsManager {
       ContainerUtil.addIfNotNull(result, getInferredNullityAnnotation((PsiParameter)listOwner));
     }
 
+    ContainerUtil.addIfNotNull(result, getInferredMutabilityAnnotation(listOwner));
+
     return result.toArray(PsiAnnotation.EMPTY_ARRAY);
   }
 

java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/ContractInferenceIndex.kt

@@ -30,7 +30,7 @@ import java.util.*
  * @author peter
  */
 
-private val gist = GistManager.getInstance().newPsiFileGist("contractInference", 6, MethodDataExternalizer) { file ->
+private val gist = GistManager.getInstance().newPsiFileGist("contractInference", 7, MethodDataExternalizer) { file ->
   indexFile(file.node.lighterAST)
 }
 
@@ -61,7 +61,7 @@ private fun calcData(tree: LighterAST, method: LighterASTNode): MethodData? {
 
   val contracts = ContractInferenceInterpreter(tree, method, body).inferContracts(statements)
 
-  val nullityVisitor = NullityInference.NullityInferenceVisitor(tree, body)
+  val nullityVisitor = NullityInference.MethodReturnInferenceVisitor(tree, body)
   val purityVisitor = PurityInference.PurityInferenceVisitor(tree, body)
   for (statement in statements) {
     walkMethodBody(tree, statement) { nullityVisitor.visitNode(it); purityVisitor.visitNode(it) }
@@ -85,12 +85,12 @@ private fun walkMethodBody(tree: LighterAST, root: LighterASTNode, processor: (L
 
 private fun createData(body: LighterASTNode,
                        contracts: List<PreContract>,
-                       nullity: NullityInferenceResult?,
+                       methodReturn: MethodReturnInferenceResult?,
                        purity: PurityInferenceResult?,
                        notNullParams: BitSet): MethodData? {
-  if (nullity == null && purity == null && contracts.isEmpty() && notNullParams.isEmpty) return null
+  if (methodReturn == null && purity == null && contracts.isEmpty() && notNullParams.isEmpty) return null
 
-  return MethodData(nullity, purity, contracts, notNullParams, body.startOffset, body.endOffset)
+  return MethodData(methodReturn, purity, contracts, notNullParams, body.startOffset, body.endOffset)
 }
 
 fun getIndexedData(method: PsiMethodImpl): MethodData? = gist.getFileData(method.containingFile)?.get(JavaStubImplUtil.getMethodStubIndex(method))

java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/DfaFactType.java

@@ -84,12 +84,18 @@ public abstract class DfaFactType<T> extends Key<T> {
     }
   };
 
-  public static final DfaFactType<Mutability> MUTABILITY = new DfaFactType<Mutability>("Mutable") {
+  public static final DfaFactType<Mutability> MUTABILITY = new DfaFactType<Mutability>("Mutability") {
     @Override
     boolean isUnknown(@NotNull Mutability fact) {
       return fact == Mutability.UNKNOWN;
     }
 
+    @NotNull
+    @Override
+    Mutability unionFacts(@NotNull Mutability left, @NotNull Mutability right) {
+      return left.union(right);
+    }
+
     @NotNull
     @Override
     Mutability calcFromVariable(@NotNull DfaVariableValue value) {

java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/MethodDataExternalizer.kt

@@ -33,7 +33,7 @@ internal object MethodDataExternalizer : DataExternalizer<Map<Int, MethodData>>
   override fun read(input: DataInput) = readSeq(input) { readINT(input) to readMethod(input) }.toMap()
 
   private fun writeMethod(out: DataOutput, data: MethodData) {
-    writeNullable(out, data.nullity) { writeNullity(out, it) }
+    writeNullable(out, data.methodReturn) { writeNullity(out, it) }
     writeNullable(out, data.purity) { writePurity(out, it) }
     writeSeq(out, data.contracts) { writeContract(out, it) }
     writeBitSet(out, data.notNullParameters)
@@ -65,14 +65,16 @@ internal object MethodDataExternalizer : DataExternalizer<Map<Int, MethodData>>
     return BitSet.valueOf(bytes)
   }
 
-  private fun writeNullity(out: DataOutput, nullity: NullityInferenceResult) = when (nullity) {
-    is NullityInferenceResult.Predefined -> { out.writeByte(0); out.writeByte(nullity.value.ordinal) }
-    is NullityInferenceResult.FromDelegate -> { out.writeByte(1); writeRanges(out, nullity.delegateCalls) }
-    else -> throw IllegalArgumentException(nullity.toString())
+  private fun writeNullity(out: DataOutput, methodReturn: MethodReturnInferenceResult) = when (methodReturn) {
+    is MethodReturnInferenceResult.Predefined -> { out.writeByte(0); out.writeByte(methodReturn.value.ordinal) }
+    is MethodReturnInferenceResult.FromDelegate -> {
+      out.writeByte(1); out.writeByte(methodReturn.value.ordinal); writeRanges(out, methodReturn.delegateCalls)
+    }
+    else -> throw IllegalArgumentException(methodReturn.toString())
   }
-  private fun readNullity(input: DataInput): NullityInferenceResult = when (input.readByte().toInt()) {
-    0 -> NullityInferenceResult.Predefined(Nullness.values()[input.readByte().toInt()])
-    else -> NullityInferenceResult.FromDelegate(readRanges(input))
+  private fun readNullity(input: DataInput): MethodReturnInferenceResult = when (input.readByte().toInt()) {
+    0 -> MethodReturnInferenceResult.Predefined(Nullness.values()[input.readByte().toInt()])
+    else -> MethodReturnInferenceResult.FromDelegate(Nullness.values()[input.readByte().toInt()], readRanges(input))
   }
 
   private fun writeRanges(out: DataOutput, ranges: List<ExpressionRange>) = writeSeq(out, ranges) { writeRange(out, it) }

java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/Mutability.java

@@ -4,42 +4,85 @@
 package com.intellij.codeInspection.dataFlow;
 
 import com.intellij.codeInsight.AnnotationUtil;
+import com.intellij.openapi.project.Project;
+import com.intellij.openapi.util.Key;
+import com.intellij.openapi.util.ModificationTracker;
+import com.intellij.openapi.util.RecursionManager;
 import com.intellij.psi.*;
-import com.intellij.psi.util.PsiTreeUtil;
-import com.intellij.psi.util.PsiUtil;
+import com.intellij.psi.impl.source.PsiMethodImpl;
+import com.intellij.psi.util.*;
+import com.intellij.testFramework.LightVirtualFile;
 import com.intellij.util.ObjectUtils;
+import com.siyeh.ig.psiutils.ClassUtils;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 import java.util.Collections;
 
+import static com.intellij.codeInspection.bytecodeAnalysis.ProjectBytecodeAnalysis.INFERRED_ANNOTATION;
+
 public enum Mutability {
   /**
    * Mutability is not known; probably value can be mutated
    */
-  UNKNOWN,
+  UNKNOWN("Unknown", null),
   /**
    * A value is known to be mutable (e.g. elements are sometimes added to the collection)
    */
-  MUTABLE,
+  MUTABLE("Modifiable", null),
   /**
    * A value is known to be immutable. For collection no elements could be added, removed or altered (though if collection
    * contains mutable elements, they still could be mutated).
    */
-  UNMODIFIABLE,
+  UNMODIFIABLE("Unmodifiable", "org.jetbrains.annotations.Unmodifiable"),
   /**
    * A value is known to be an immutable view over a possibly mutable value: it cannot be mutated directly using this
    * reference; however subsequent reads (e.g. {@link java.util.Collection#size}) may return different results if the
    * underlying value is mutated by somebody else.
    */
-  UNMODIFIABLE_VIEW;
+  UNMODIFIABLE_VIEW("Unmodifiable view", "org.jetbrains.annotations.UnmodifiableView");
 
-  public static final String UNMODIFIABLE_ANNOTATION = "org.jetbrains.annotations.Unmodifiable";
-  public static final String UNMODIFIABLE_VIEW_ANNOTATION = "org.jetbrains.annotations.UnmodifiableView";
+  public static final @NotNull String UNMODIFIABLE_ANNOTATION = UNMODIFIABLE.myAnnotation;
+  public static final @NotNull String UNMODIFIABLE_VIEW_ANNOTATION = UNMODIFIABLE_VIEW.myAnnotation;
+  private final String myName;
+  private final String myAnnotation;
+  private final Key<CachedValue<PsiAnnotation>> myKey;
+
+  Mutability(String name, String annotation) {
+    myName = name;
+    myAnnotation = annotation;
+    myKey = annotation == null ? null : Key.create(annotation);
+  }
+
+  @Override
+  public String toString() {
+    return myName;
+  }
 
   public boolean isUnmodifiable() {
     return this == UNMODIFIABLE || this == UNMODIFIABLE_VIEW;
   }
 
+  @NotNull
+  public Mutability union(Mutability other) {
+    if (this == other) return this;
+    if (this == MUTABLE || other == MUTABLE) return MUTABLE;
+    if (this == UNKNOWN || other == UNKNOWN) return UNKNOWN;
+    if (this == UNMODIFIABLE_VIEW || other == UNMODIFIABLE_VIEW) return UNMODIFIABLE_VIEW;
+    return UNMODIFIABLE;
+  }
+
+  @Nullable
+  public PsiAnnotation asAnnotation(Project project) {
+    if (myAnnotation == null) return null;
+    return CachedValuesManager.getManager(project).getCachedValue(project, myKey, () -> {
+      PsiAnnotation annotation = JavaPsiFacade.getElementFactory(project).createAnnotationFromText("@" + myAnnotation, null);
+      annotation.putUserData(INFERRED_ANNOTATION, Boolean.TRUE);
+      ((LightVirtualFile)annotation.getContainingFile().getViewProvider().getVirtualFile()).setWritable(false);
+      return CachedValueProvider.Result.create(annotation, ModificationTracker.NEVER_CHANGED);
+    }, false);
+  }
+
   /**
    * Returns a mutability of the supplied element, if known. The element could be a method
    * (in this case the return value mutability is returned), a method parameter
@@ -84,9 +127,35 @@ public enum Mutability {
       PsiExpression initializer = PsiUtil.skipParenthesizedExprDown(((PsiField)owner).getInitializer());
       if (initializer instanceof PsiMethodCallExpression) {
         PsiMethod method = ((PsiMethodCallExpression)initializer).resolveMethod();
-        return method == null ? UNKNOWN : getMutability(method);
+        if (method == null) {
+          return UNKNOWN;
+        }
+        if (ClassUtils.isImmutable(method.getReturnType())) return UNMODIFIABLE;
+        return getMutability(method);
       }
     }
-    return UNKNOWN;
+    return inferMutability(owner);
+  }
+
+  public static Mutability inferMutability(PsiModifierListOwner owner) {
+    if (!(owner instanceof PsiMethodImpl)) return UNKNOWN;
+    PsiMethodImpl method = (PsiMethodImpl)owner;
+    if (!InferenceFromSourceUtil.shouldInferFromSource(method)) {
+      return UNKNOWN;
+    }
+
+    PsiType type = method.getReturnType();
+    if (type == null || ClassUtils.isImmutable(type)) {
+      return UNKNOWN;
+    }
+
+    return CachedValuesManager.getCachedValue(method, () -> {
+      MethodData data = ContractInferenceIndexKt.getIndexedData(method);
+      MethodReturnInferenceResult result = data == null ? null : data.getMethodReturn();
+      Mutability mutability = result == null ? null : RecursionManager
+        .doPreventingRecursion(method, true, () -> result.getMutability(method, data.methodBody(method)));
+      if (mutability == null) mutability = UNKNOWN;
+      return CachedValueProvider.Result.create(mutability, method, PsiModificationTracker.JAVA_STRUCTURE_MODIFICATION_COUNT);
+    });
   }
 }

java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/NullityInference.java

@@ -60,7 +60,7 @@ public class NullityInference {
 
     return CachedValuesManager.getCachedValue(method, () -> {
       MethodData data = ContractInferenceIndexKt.getIndexedData(method);
-      NullityInferenceResult result = data == null ? null : data.getNullity();
+      MethodReturnInferenceResult result = data == null ? null : data.getMethodReturn();
       Nullness nullness = result == null ? null : RecursionManager.doPreventingRecursion(method, true, () -> result.getNullness(method, data.methodBody(method)));
       if (nullness == null) nullness = Nullness.UNKNOWN;
       return CachedValueProvider.Result.create(nullness, method, PsiModificationTracker.JAVA_STRUCTURE_MODIFICATION_COUNT);
@@ -90,7 +90,7 @@ public class NullityInference {
     });
   }
 
-  static class NullityInferenceVisitor {
+  static class MethodReturnInferenceVisitor {
     private final LighterAST tree;
     private final LighterASTNode body;
     private boolean hasErrors;
@@ -101,7 +101,7 @@ public class NullityInference {
     Set<String> assignments = ContainerUtil.newHashSet();
     Set<String> returnedCheckedVars = ContainerUtil.newHashSet();
 
-    NullityInferenceVisitor(LighterAST tree, LighterASTNode body) {
+    MethodReturnInferenceVisitor(LighterAST tree, LighterASTNode body) {
       this.tree = tree;
       this.body = body;
     }
@@ -193,15 +193,15 @@ public class NullityInference {
     private boolean isNonNullCondition(@Nullable LighterASTNode expr, LighterASTNode var) {
       expr = skipParenthesesCastsDown(tree, expr);
       if (expr == null) return false;
-      
+
       IElementType type = expr.getTokenType();
       if (type == BINARY_EXPRESSION || type == POLYADIC_EXPRESSION) {
         List<LighterASTNode> operands = getExpressionChildren(tree, expr);
         if (firstChildOfType(tree, expr, JavaTokenType.NE) != null) {
           return operands.size() == 2 && isNullLiteral(operands.get(1)) && isReferenceTo(operands.get(0), var);
         }
-        
-        return firstChildOfType(tree, expr, JavaTokenType.ANDAND) != null && ContainerUtil.exists(operands, e -> isNonNullCondition(e, var)); 
+
+        return firstChildOfType(tree, expr, JavaTokenType.ANDAND) != null && ContainerUtil.exists(operands, e -> isNonNullCondition(e, var));
       }
 
       return type == INSTANCE_OF_EXPRESSION && isReferenceTo(expr, var);
@@ -209,8 +209,8 @@ public class NullityInference {
 
     private boolean isReferenceTo(@NotNull LighterASTNode expr, @NotNull LighterASTNode var) {
       LighterASTNode operand = skipParenthesesCastsDown(tree, findExpressionChild(tree, expr));
-      if (operand == null || 
-          operand.getTokenType() != REFERENCE_EXPRESSION || 
+      if (operand == null ||
+          operand.getTokenType() != REFERENCE_EXPRESSION ||
           !Objects.equals(getNameIdentifierText(tree, operand), getNameIdentifierText(tree, operand))) {
         return false;
       }
@@ -222,7 +222,7 @@ public class NullityInference {
     }
 
     @Nullable
-    NullityInferenceResult getResult() {
+    MethodReturnInferenceResult getResult() {
       if (!returnedCheckedVars.isEmpty()) {
         if (ContainerUtil.exists(returnedCheckedVars, name -> !assignments.contains(name))) {
           hasNotNulls = true;
@@ -230,19 +230,25 @@ public class NullityInference {
           hasUnknowns = true;
         }
       }
-      
+
+      List<ExpressionRange> delegateCalls = null;
+      if (delegates.size() == 1) {
+        delegateCalls = ContainerUtil.newArrayList(delegates.get(delegates.keySet().iterator().next()));
+      }
       if (hasNulls) {
-        return new NullityInferenceResult.Predefined(Nullness.NULLABLE);
+        return delegateCalls == null || hasNotNulls || hasErrors || hasUnknowns
+               ? new MethodReturnInferenceResult.Predefined(Nullness.NULLABLE)
+               : new MethodReturnInferenceResult.FromDelegate(Nullness.NULLABLE, delegateCalls);
       }
       if (hasErrors || hasUnknowns || delegates.size() > 1) {
         return null;
       }
-      if (delegates.size() == 1) {
-        return new NullityInferenceResult.FromDelegate(ContainerUtil.newArrayList(delegates.get(delegates.keySet().iterator().next())));
+      if (delegateCalls != null) {
+        return new MethodReturnInferenceResult.FromDelegate(hasNotNulls ? Nullness.NOT_NULL : Nullness.UNKNOWN, delegateCalls);
       }
 
       if (hasNotNulls) {
-        return new NullityInferenceResult.Predefined(Nullness.NOT_NULL);
+        return new MethodReturnInferenceResult.Predefined(Nullness.NOT_NULL);
       }
       return null;
     }

java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/inferenceResults.kt

@@ -25,6 +25,7 @@ import com.intellij.psi.util.CachedValueProvider
 import com.intellij.psi.util.CachedValuesManager
 import com.intellij.psi.util.PsiTreeUtil
 import com.intellij.psi.util.PsiUtil
+import com.siyeh.ig.psiutils.ClassUtils
 import java.util.*
 
 /**
@@ -89,11 +90,12 @@ data class PurityInferenceResult(internal val mutatedRefs: List<ExpressionRange>
 }
 
 
-interface NullityInferenceResult {
+interface MethodReturnInferenceResult {
   fun getNullness(method: PsiMethod, body: () -> PsiCodeBlock): Nullness
+  fun getMutability(method: PsiMethod, body: () -> PsiCodeBlock): Mutability = Mutability.UNKNOWN
 
   @Suppress("EqualsOrHashCode")
-  data class Predefined(internal val value: Nullness) : NullityInferenceResult {
+  data class Predefined(internal val value: Nullness) : MethodReturnInferenceResult {
     override fun hashCode() = value.ordinal
     override fun getNullness(method: PsiMethod, body: () -> PsiCodeBlock) = when {
       value == Nullness.NULLABLE && InferenceFromSourceUtil.suppressNullable(method) -> Nullness.UNKNOWN
@@ -101,10 +103,33 @@ interface NullityInferenceResult {
     }
   }
 
-  data class FromDelegate(internal val delegateCalls: List<ExpressionRange>) : NullityInferenceResult {
-    override fun getNullness(method: PsiMethod, body: () -> PsiCodeBlock) = when {
-      delegateCalls.all { range -> isNotNullCall(range, body()) } -> Nullness.NOT_NULL
-      else -> Nullness.UNKNOWN
+  data class FromDelegate(internal val value: Nullness, internal val delegateCalls: List<ExpressionRange>) : MethodReturnInferenceResult {
+    override fun getNullness(method: PsiMethod, body: () -> PsiCodeBlock): Nullness {
+      if (value == Nullness.NULLABLE) {
+        return if (InferenceFromSourceUtil.suppressNullable(method)) Nullness.UNKNOWN else Nullness.NULLABLE
+      }
+      return when {
+        delegateCalls.all { range -> isNotNullCall(range, body()) } -> Nullness.NOT_NULL
+        else -> Nullness.UNKNOWN
+      }
+    }
+
+    override fun getMutability(method: PsiMethod, body: () -> PsiCodeBlock): Mutability {
+      if (value == Nullness.NOT_NULL) {
+        return Mutability.UNKNOWN
+      }
+      return delegateCalls.stream().map { range -> getDelegateMutability(range, body()) }.reduce(Mutability::union).orElse(
+        Mutability.UNKNOWN)
+    }
+
+    private fun getDelegateMutability(delegate: ExpressionRange, body: PsiCodeBlock): Mutability {
+      val call = delegate.restoreExpression(body) as PsiMethodCallExpression
+      val target = call.resolveMethod()
+      return when {
+        target == null -> Mutability.UNKNOWN
+        ClassUtils.isImmutable(target.returnType) -> Mutability.UNMODIFIABLE
+        else -> Mutability.getMutability(target)
+      }
     }
 
     private fun isNotNullCall(delegate: ExpressionRange, body: PsiCodeBlock): Boolean {
@@ -118,7 +143,7 @@ interface NullityInferenceResult {
 }
 
 data class MethodData(
-    val nullity: NullityInferenceResult?,
+    val methodReturn: MethodReturnInferenceResult?,
     val purity: PurityInferenceResult?,
     val contracts: List<PreContract>,
     val notNullParameters: BitSet,

java/java-tests/testData/inspection/dataFlow/fixture/MutabilityInferred.java

@@ -0,0 +1,37 @@
+import java.util.*;
+import org.jetbrains.annotations.*;
+
+public class MutabilityInferred {
+  @Nullable
+  static List<String> getListNullOrImmutable(int x) {
+    if(x == 0) return null;
+    return Collections.singletonList("foo");
+  }
+
+  static List<String> getListImmutable(int x) {
+    if(x == 0) return Collections.singletonList("bar");
+    return Collections.singletonList("foo");
+  }
+
+  static List<String> getListImmutableOrMutable(int x) {
+    if(x == 0) return new ArrayList<>();
+    return Collections.singletonList("foo");
+  }
+
+  static native List<String> getListUnknown(int x);
+
+  @Nullable
+  static List<String> getListVar(boolean b) {
+    List<String> list = getListUnknown(0);
+    if (list != null) return list;
+    if (b) return Collections.singletonList("xyz");
+    return null;
+  }
+
+  void test() {
+    getListNullOrImmutable(0).<warning descr="Immutable object is modified"><warning descr="Method invocation 'add' may produce 'java.lang.NullPointerException'">add</warning></warning>("a");
+    getListImmutable(0).<warning descr="Immutable object is modified">add</warning>("b");
+    getListImmutableOrMutable(0).add("c");
+    getListVar(false).<warning descr="Method invocation 'add' may produce 'java.lang.NullPointerException'">add</warning>("d");
+  }
+}

java/java-tests/testSrc/com/intellij/java/codeInspection/DataFlowInspection8Test.java

@@ -213,9 +213,8 @@ public class DataFlowInspection8Test extends DataFlowInspectionTestCase {
     doTest();
   }
 
-  public void testMutabilityJdk() {
-    doTest();
-  }
+  public void testMutabilityJdk() { doTest(); }
+  public void testMutabilityInferred() { doTest(); }
 
   public void testPrimitiveGetters() { doTest(); }
   public void testUnknownOnStack() { doTest(); }

plugins/InspectionGadgets/InspectionGadgetsAnalysis/src/com/siyeh/ig/psiutils/ClassUtils.java

@@ -116,7 +116,8 @@ public class ClassUtils {
     return integralTypes.contains(type);
   }
 
-  public static boolean isImmutable(PsiType type) {
+  @Contract("null -> false")
+  public static boolean isImmutable(@Nullable PsiType type) {
     if (TypeConversionUtil.isPrimitiveAndNotNull(type)) {
       return true;
     }
@@ -124,7 +125,8 @@ public class ClassUtils {
     if (aClass == null) {
       return false;
     }
-    if (immutableTypes.contains(aClass.getQualifiedName())) {
+    String qualifiedName = aClass.getQualifiedName();
+    if (immutableTypes.contains(qualifiedName) || (qualifiedName != null && qualifiedName.startsWith("com.google.common.collect.Immutable"))) {
       return true;
     }
     return JCiPUtil.isImmutable(aClass);