private void analyzeDfaWithNestedClosures(
      PsiElement scope,
      ProblemsHolder holder,
      StandardDataFlowRunner dfaRunner,
      Collection<DfaMemoryState> initialStates) {
    final DataFlowInstructionVisitor visitor = new DataFlowInstructionVisitor(dfaRunner);
    final RunnerResult rc =
        dfaRunner.analyzeMethod(scope, visitor, IGNORE_ASSERT_STATEMENTS, initialStates);
    if (rc == RunnerResult.OK) {
      createDescription(dfaRunner, holder, visitor);

      MultiMap<PsiElement, DfaMemoryState> nestedClosures = dfaRunner.getNestedClosures();
      for (PsiElement closure : nestedClosures.keySet()) {
        analyzeDfaWithNestedClosures(closure, holder, dfaRunner, nestedClosures.get(closure));
      }
    } else if (rc == RunnerResult.TOO_COMPLEX) {
      if (scope.getParent() instanceof PsiMethod) {
        PsiMethod method = (PsiMethod) scope.getParent();
        final PsiIdentifier name = method.getNameIdentifier();
        if (name != null) { // Might be null for synthetic methods like JSP page.
          holder.registerProblem(
              name,
              InspectionsBundle.message("dataflow.too.complex"),
              ProblemHighlightType.WEAK_WARNING);
        }
      }
    }
  }
 private void handleBranchingInstruction(
     ProblemsHolder holder,
     StandardInstructionVisitor visitor,
     Set<Instruction> trueSet,
     Set<Instruction> falseSet,
     HashSet<PsiElement> reportedAnchors,
     BranchingInstruction instruction,
     final boolean onTheFly) {
   PsiElement psiAnchor = instruction.getPsiAnchor();
   boolean underBinary = isAtRHSOfBooleanAnd(psiAnchor);
   if (instruction instanceof InstanceofInstruction
       && visitor.isInstanceofRedundant((InstanceofInstruction) instruction)) {
     if (visitor.canBeNull((BinopInstruction) instruction)) {
       holder.registerProblem(
           psiAnchor,
           InspectionsBundle.message("dataflow.message.redundant.instanceof"),
           new RedundantInstanceofFix());
     } else {
       final LocalQuickFix localQuickFix = createSimplifyBooleanExpressionFix(psiAnchor, true);
       holder.registerProblem(
           psiAnchor,
           InspectionsBundle.message(
               underBinary
                   ? "dataflow.message.constant.condition.when.reached"
                   : "dataflow.message.constant.condition",
               Boolean.toString(true)),
           localQuickFix == null ? null : new LocalQuickFix[] {localQuickFix});
     }
   } else if (psiAnchor instanceof PsiSwitchLabelStatement) {
     if (falseSet.contains(instruction)) {
       holder.registerProblem(
           psiAnchor, InspectionsBundle.message("dataflow.message.unreachable.switch.label"));
     }
   } else if (psiAnchor != null
       && !reportedAnchors.contains(psiAnchor)
       && !isFlagCheck(psiAnchor)) {
     boolean evaluatesToTrue = trueSet.contains(instruction);
     final PsiElement parent = psiAnchor.getParent();
     if (parent instanceof PsiAssignmentExpression
         && ((PsiAssignmentExpression) parent).getLExpression() == psiAnchor) {
       holder.registerProblem(
           psiAnchor,
           InspectionsBundle.message(
               "dataflow.message.pointless.assignment.expression",
               Boolean.toString(evaluatesToTrue)),
           createConditionalAssignmentFixes(
               evaluatesToTrue, (PsiAssignmentExpression) parent, onTheFly));
     } else if (!skipReportingConstantCondition(visitor, psiAnchor, evaluatesToTrue)) {
       final LocalQuickFix fix = createSimplifyBooleanExpressionFix(psiAnchor, evaluatesToTrue);
       String message =
           InspectionsBundle.message(
               underBinary
                   ? "dataflow.message.constant.condition.when.reached"
                   : "dataflow.message.constant.condition",
               Boolean.toString(evaluatesToTrue));
       holder.registerProblem(psiAnchor, message, fix == null ? null : new LocalQuickFix[] {fix});
     }
     reportedAnchors.add(psiAnchor);
   }
 }
  @Nullable
  private Collection<DfaMemoryState> createInitialStates(
      @NotNull PsiElement psiBlock, @NotNull InstructionVisitor visitor) {
    PsiElement container =
        PsiTreeUtil.getParentOfType(psiBlock, PsiClass.class, PsiLambdaExpression.class);
    if (container != null
        && (!(container instanceof PsiClass)
            || PsiUtil.isLocalOrAnonymousClass((PsiClass) container))) {
      final PsiElement parent = container.getParent();
      final PsiCodeBlock block = DfaPsiUtil.getTopmostBlockInSameClass(parent);
      if (block != null) {
        final RunnerResult result = analyzeMethod(block, visitor);
        if (result == RunnerResult.OK) {
          final Collection<DfaMemoryState> closureStates =
              myNestedClosures.get(DfaPsiUtil.getTopmostBlockInSameClass(psiBlock));
          if (!closureStates.isEmpty()) {
            return closureStates;
          }
        }
        return null;
      }
    }

    return Collections.singletonList(createMemoryState());
  }
 private static SimplifyBooleanExpressionFix createIntention(PsiElement element, boolean value) {
   if (!(element instanceof PsiExpression)) return null;
   final PsiExpression expression = (PsiExpression) element;
   while (element.getParent() instanceof PsiExpression) {
     element = element.getParent();
   }
   final SimplifyBooleanExpressionFix fix = new SimplifyBooleanExpressionFix(expression, value);
   // simplify intention already active
   if (!fix.isAvailable()
       || SimplifyBooleanExpressionFix.canBeSimplified((PsiExpression) element)) {
     return null;
   }
   return fix;
 }
  private static boolean isAtRHSOfBooleanAnd(PsiElement expr) {
    PsiElement cur = expr;

    while (cur != null && !(cur instanceof PsiMember)) {
      PsiElement parent = cur.getParent();

      if (parent instanceof PsiBinaryExpression
          && cur == ((PsiBinaryExpression) parent).getROperand()) {
        return true;
      }

      cur = parent;
    }

    return false;
  }
  private void reportNullableReturns(
      DataFlowInstructionVisitor visitor,
      ProblemsHolder holder,
      Set<PsiElement> reportedAnchors,
      @NotNull PsiElement block) {
    final PsiMethod method = getScopeMethod(block);
    if (method == null || NullableStuffInspectionBase.isNullableNotInferred(method, true)) return;

    boolean notNullRequired = NullableNotNullManager.isNotNull(method);
    if (!notNullRequired && !SUGGEST_NULLABLE_ANNOTATIONS) return;

    PsiType returnType = method.getReturnType();
    // no warnings in void lambdas, where the expression is not returned anyway
    if (block instanceof PsiExpression
        && block.getParent() instanceof PsiLambdaExpression
        && returnType == PsiType.VOID) return;

    // no warnings for Void methods, where only null can be possibly returned
    if (returnType == null || returnType.equalsToText(CommonClassNames.JAVA_LANG_VOID)) return;

    for (PsiElement statement : visitor.getProblems(NullabilityProblem.nullableReturn)) {
      assert statement instanceof PsiExpression;
      final PsiExpression expr = (PsiExpression) statement;
      if (!reportedAnchors.add(expr)) continue;

      if (notNullRequired) {
        final String text =
            isNullLiteralExpression(expr)
                ? InspectionsBundle.message("dataflow.message.return.null.from.notnull")
                : InspectionsBundle.message("dataflow.message.return.nullable.from.notnull");
        holder.registerProblem(expr, text);
      } else if (AnnotationUtil.isAnnotatingApplicable(statement)) {
        final NullableNotNullManager manager =
            NullableNotNullManager.getInstance(expr.getProject());
        final String defaultNullable = manager.getDefaultNullable();
        final String presentableNullable = StringUtil.getShortName(defaultNullable);
        final String text =
            isNullLiteralExpression(expr)
                ? InspectionsBundle.message(
                    "dataflow.message.return.null.from.notnullable", presentableNullable)
                : InspectionsBundle.message(
                    "dataflow.message.return.nullable.from.notnullable", presentableNullable);
        final LocalQuickFix[] fixes =
            PsiTreeUtil.getParentOfType(expr, PsiMethod.class, PsiLambdaExpression.class)
                    instanceof PsiLambdaExpression
                ? LocalQuickFix.EMPTY_ARRAY
                : new LocalQuickFix[] {
                  new AnnotateMethodFix(
                      defaultNullable, ArrayUtil.toStringArray(manager.getNotNulls())) {
                    @Override
                    public int shouldAnnotateBaseMethod(
                        PsiMethod method, PsiMethod superMethod, Project project) {
                      return 1;
                    }
                  }
                };
        holder.registerProblem(expr, text, fixes);
      }
    }
  }
 private static boolean onTheLeftSideOfConditionalAssignment(final PsiElement psiAnchor) {
   final PsiElement parent = psiAnchor.getParent();
   if (parent instanceof PsiAssignmentExpression) {
     final PsiAssignmentExpression expression = (PsiAssignmentExpression) parent;
     if (expression.getLExpression() == psiAnchor) return true;
   }
   return false;
 }
  private static boolean isCompileConstantInIfCondition(PsiElement element) {
    if (!(element instanceof PsiReferenceExpression)) return false;
    PsiElement resolved = ((PsiReferenceExpression) element).resolve();
    if (!(resolved instanceof PsiField)) return false;
    PsiField field = (PsiField) resolved;

    if (!field.hasModifierProperty(PsiModifier.FINAL)) return false;
    if (!field.hasModifierProperty(PsiModifier.STATIC)) return false;

    PsiElement parent = element.getParent();
    if (parent instanceof PsiPrefixExpression
        && ((PsiPrefixExpression) parent).getOperationTokenType() == JavaTokenType.EXCL) {
      element = parent;
      parent = parent.getParent();
    }
    return parent instanceof PsiIfStatement && ((PsiIfStatement) parent).getCondition() == element;
  }
 @Nullable
 private static PsiMethod getScopeMethod(PsiElement block) {
   PsiElement parent = block.getParent();
   if (parent instanceof PsiMethod) return (PsiMethod) parent;
   if (parent instanceof PsiLambdaExpression)
     return LambdaUtil.getFunctionalInterfaceMethod(
         ((PsiLambdaExpression) parent).getFunctionalInterfaceType());
   return null;
 }
 @Override
 public void applyFix(@NotNull Project project, @NotNull ProblemDescriptor descriptor) {
   if (!FileModificationService.getInstance()
       .preparePsiElementForWrite(descriptor.getPsiElement())) return;
   final PsiElement psiElement = descriptor.getPsiElement();
   if (psiElement instanceof PsiInstanceOfExpression) {
     try {
       final PsiExpression compareToNull =
           JavaPsiFacade.getInstance(psiElement.getProject())
               .getElementFactory()
               .createExpressionFromText(
                   ((PsiInstanceOfExpression) psiElement).getOperand().getText() + " != null",
                   psiElement.getParent());
       psiElement.replace(compareToNull);
     } catch (IncorrectOperationException e) {
       LOG.error(e);
     }
   }
 }
  private void reportNullableArgumentsPassedToNonAnnotated(
      DataFlowInstructionVisitor visitor, ProblemsHolder holder, Set<PsiElement> reportedAnchors) {
    for (PsiElement expr :
        visitor.getProblems(NullabilityProblem.passingNullableArgumentToNonAnnotatedParameter)) {
      if (reportedAnchors.contains(expr)) continue;

      final String text =
          isNullLiteralExpression(expr)
              ? "Passing <code>null</code> argument to non annotated parameter"
              : "Argument <code>#ref</code> #loc might be null but passed to non annotated parameter";
      LocalQuickFix[] fixes =
          createNPEFixes((PsiExpression) expr, (PsiExpression) expr, holder.isOnTheFly());
      final PsiElement parent = expr.getParent();
      if (parent instanceof PsiExpressionList) {
        final int idx = ArrayUtilRt.find(((PsiExpressionList) parent).getExpressions(), expr);
        if (idx > -1) {
          final PsiElement gParent = parent.getParent();
          if (gParent instanceof PsiCallExpression) {
            final PsiMethod psiMethod = ((PsiCallExpression) gParent).resolveMethod();
            if (psiMethod != null
                && psiMethod.getManager().isInProject(psiMethod)
                && AnnotationUtil.isAnnotatingApplicable(psiMethod)) {
              final PsiParameter[] parameters = psiMethod.getParameterList().getParameters();
              if (idx < parameters.length) {
                final AddNullableAnnotationFix addNullableAnnotationFix =
                    new AddNullableAnnotationFix(parameters[idx]);
                fixes =
                    fixes == null
                        ? new LocalQuickFix[] {addNullableAnnotationFix}
                        : ArrayUtil.append(fixes, addNullableAnnotationFix);
                holder.registerProblem(expr, text, fixes);
                reportedAnchors.add(expr);
              }
            }
          }
        }
      }
    }
  }
 private static boolean isAssertionEffectively(PsiElement psiAnchor, boolean evaluatesToTrue) {
   PsiElement parent = psiAnchor.getParent();
   if (parent instanceof PsiAssertStatement) {
     return evaluatesToTrue;
   }
   if (parent instanceof PsiIfStatement && psiAnchor == ((PsiIfStatement) parent).getCondition()) {
     PsiStatement thenBranch = ((PsiIfStatement) parent).getThenBranch();
     if (thenBranch instanceof PsiThrowStatement) {
       return !evaluatesToTrue;
     }
     if (thenBranch instanceof PsiBlockStatement) {
       PsiStatement[] statements = ((PsiBlockStatement) thenBranch).getCodeBlock().getStatements();
       if (statements.length == 1 && statements[0] instanceof PsiThrowStatement) {
         return !evaluatesToTrue;
       }
     }
   }
   return false;
 }
  private void createDescription(
      StandardDataFlowRunner runner, ProblemsHolder holder, DataFlowInstructionVisitor visitor) {
    Pair<Set<Instruction>, Set<Instruction>> constConditions =
        runner.getConstConditionalExpressions();
    Set<Instruction> trueSet = constConditions.getFirst();
    Set<Instruction> falseSet = constConditions.getSecond();

    ArrayList<Instruction> allProblems = new ArrayList<Instruction>();
    allProblems.addAll(trueSet);
    allProblems.addAll(falseSet);
    allProblems.addAll(runner.getCCEInstructions());
    allProblems.addAll(StandardDataFlowRunner.getRedundantInstanceofs(runner, visitor));

    HashSet<PsiElement> reportedAnchors = new HashSet<PsiElement>();
    for (PsiElement element : visitor.getProblems(NullabilityProblem.callNPE)) {
      if (reportedAnchors.add(element)) {
        reportCallMayProduceNpe(holder, (PsiMethodCallExpression) element, holder.isOnTheFly());
      }
    }
    for (PsiElement element : visitor.getProblems(NullabilityProblem.fieldAccessNPE)) {
      if (reportedAnchors.add(element)) {
        PsiElement parent = element.getParent();
        PsiElement fieldAccess =
            parent instanceof PsiArrayAccessExpression || parent instanceof PsiReferenceExpression
                ? parent
                : element;
        reportFieldAccessMayProduceNpe(holder, element, (PsiExpression) fieldAccess);
      }
    }

    for (Instruction instruction : allProblems) {
      if (instruction instanceof TypeCastInstruction
          && reportedAnchors.add(
              ((TypeCastInstruction) instruction).getCastExpression().getCastType())) {
        reportCastMayFail(holder, (TypeCastInstruction) instruction);
      } else if (instruction instanceof BranchingInstruction) {
        handleBranchingInstruction(
            holder,
            visitor,
            trueSet,
            falseSet,
            reportedAnchors,
            (BranchingInstruction) instruction);
      }
    }

    reportNullableArguments(visitor, holder, reportedAnchors);
    reportNullableAssignments(visitor, holder, reportedAnchors);
    reportUnboxedNullables(visitor, holder, reportedAnchors);
    if (!runner.isInNullableMethod()
        && runner.isInMethod()
        && (runner.isInNotNullMethod() || SUGGEST_NULLABLE_ANNOTATIONS)) {
      reportNullableReturns(runner, visitor, holder, reportedAnchors);
    }
    if (SUGGEST_NULLABLE_ANNOTATIONS) {
      reportNullableArgumentsPassedToNonAnnotated(visitor, holder, reportedAnchors);
    }

    if (REPORT_CONSTANT_REFERENCE_VALUES) {
      reportConstantReferenceValues(holder, visitor, reportedAnchors);
    }
  }
  @NotNull
  final RunnerResult analyzeMethod(
      @NotNull PsiElement psiBlock,
      @NotNull InstructionVisitor visitor,
      boolean ignoreAssertions,
      @NotNull Collection<DfaMemoryState> initialStates) {
    if (PsiTreeUtil.findChildOfType(psiBlock, OuterLanguageElement.class) != null)
      return RunnerResult.NOT_APPLICABLE;

    try {
      final ControlFlow flow =
          new ControlFlowAnalyzer(myValueFactory, psiBlock, ignoreAssertions).buildControlFlow();
      if (flow == null) return RunnerResult.NOT_APPLICABLE;
      int[] loopNumber = LoopAnalyzer.calcInLoop(flow);

      int endOffset = flow.getInstructionCount();
      myInstructions = flow.getInstructions();
      myNestedClosures.clear();

      Set<Instruction> joinInstructions = ContainerUtil.newHashSet();
      for (int index = 0; index < myInstructions.length; index++) {
        Instruction instruction = myInstructions[index];
        if (instruction instanceof GotoInstruction) {
          joinInstructions.add(myInstructions[((GotoInstruction) instruction).getOffset()]);
        } else if (instruction instanceof ConditionalGotoInstruction) {
          joinInstructions.add(
              myInstructions[((ConditionalGotoInstruction) instruction).getOffset()]);
        } else if (instruction instanceof MethodCallInstruction
            && !((MethodCallInstruction) instruction).getContracts().isEmpty()) {
          joinInstructions.add(myInstructions[index + 1]);
        }
      }

      if (LOG.isDebugEnabled()) {
        LOG.debug("Analyzing code block: " + psiBlock.getText());
        for (int i = 0; i < myInstructions.length; i++) {
          LOG.debug(i + ": " + myInstructions[i]);
        }
      }
      // for (int i = 0; i < myInstructions.length; i++) System.out.println(i + ": " +
      // myInstructions[i].toString());

      Integer tooExpensiveHash = psiBlock.getUserData(TOO_EXPENSIVE_HASH);
      if (tooExpensiveHash != null && tooExpensiveHash == psiBlock.getText().hashCode()) {
        LOG.debug("Too complex because hasn't changed since being too complex already");
        return RunnerResult.TOO_COMPLEX;
      }

      final StateQueue queue = new StateQueue();
      for (final DfaMemoryState initialState : initialStates) {
        queue.offer(new DfaInstructionState(myInstructions[0], initialState));
      }

      MultiMap<BranchingInstruction, DfaMemoryState> processedStates = MultiMap.createSet();
      MultiMap<BranchingInstruction, DfaMemoryState> incomingStates = MultiMap.createSet();

      long msLimit =
          shouldCheckTimeLimit()
              ? Registry.intValue("ide.dfa.time.limit.online")
              : Registry.intValue("ide.dfa.time.limit.offline");
      WorkingTimeMeasurer measurer = new WorkingTimeMeasurer(msLimit * 1000 * 1000);
      int count = 0;
      while (!queue.isEmpty()) {
        List<DfaInstructionState> states = queue.getNextInstructionStates(joinInstructions);
        for (DfaInstructionState instructionState : states) {
          if (count++ % 1024 == 0 && measurer.isTimeOver()) {
            LOG.debug("Too complex because the analysis took too long");
            psiBlock.putUserData(TOO_EXPENSIVE_HASH, psiBlock.getText().hashCode());
            return RunnerResult.TOO_COMPLEX;
          }
          ProgressManager.checkCanceled();

          if (LOG.isDebugEnabled()) {
            LOG.debug(instructionState.toString());
          }
          // System.out.println(instructionState.toString());

          Instruction instruction = instructionState.getInstruction();

          if (instruction instanceof BranchingInstruction) {
            BranchingInstruction branching = (BranchingInstruction) instruction;
            Collection<DfaMemoryState> processed = processedStates.get(branching);
            if (processed.contains(instructionState.getMemoryState())) {
              continue;
            }
            if (processed.size() > MAX_STATES_PER_BRANCH) {
              LOG.debug("Too complex because too many different possible states");
              return RunnerResult.TOO_COMPLEX; // Too complex :(
            }
            if (loopNumber[branching.getIndex()] != 0) {
              processedStates.putValue(branching, instructionState.getMemoryState().createCopy());
            }
          }

          DfaInstructionState[] after = acceptInstruction(visitor, instructionState);
          for (DfaInstructionState state : after) {
            Instruction nextInstruction = state.getInstruction();
            if (nextInstruction.getIndex() >= endOffset) {
              continue;
            }
            handleStepOutOfLoop(
                instruction,
                nextInstruction,
                loopNumber,
                processedStates,
                incomingStates,
                states,
                after,
                queue);
            if (nextInstruction instanceof BranchingInstruction) {
              BranchingInstruction branching = (BranchingInstruction) nextInstruction;
              if (processedStates.get(branching).contains(state.getMemoryState())
                  || incomingStates.get(branching).contains(state.getMemoryState())) {
                continue;
              }
              if (loopNumber[branching.getIndex()] != 0) {
                incomingStates.putValue(branching, state.getMemoryState().createCopy());
              }
            }
            queue.offer(state);
          }
        }
      }

      psiBlock.putUserData(TOO_EXPENSIVE_HASH, null);
      LOG.debug("Analysis ok");
      return RunnerResult.OK;
    } catch (ArrayIndexOutOfBoundsException e) {
      LOG.error(psiBlock.getText(), e);
      return RunnerResult.ABORTED;
    } catch (EmptyStackException e) {
      LOG.error(psiBlock.getText(), e);
      return RunnerResult.ABORTED;
    }
  }