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);
        }
      }
    }
  }
  @Override
  public CommonProblemDescriptor[] checkElement(
      @NotNull RefEntity refEntity,
      @NotNull AnalysisScope scope,
      @NotNull final InspectionManager manager,
      @NotNull final GlobalInspectionContext globalContext) {
    if (refEntity instanceof RefMethod) {
      RefMethod refMethod = (RefMethod) refEntity;
      if (!refMethod.isReferenced()) return null;
      if (hasNonInvertedCalls(refMethod)) return null;
      if (!refMethod.getSuperMethods().isEmpty()) return null;
      final PsiMethod psiMethod = (PsiMethod) refMethod.getElement();
      final PsiIdentifier psiIdentifier = psiMethod.getNameIdentifier();
      if (psiIdentifier != null) {
        final Collection<RefElement> inReferences = refMethod.getInReferences();
        if (inReferences.size() == 1) {
          final RefElement refElement = inReferences.iterator().next();
          final PsiElement usagesContainer = refElement.getElement();
          if (usagesContainer == null) return null;
          if (ReferencesSearch.search(psiMethod, new LocalSearchScope(usagesContainer))
              .forEach(
                  new Processor<PsiReference>() {
                    private final Set<PsiReference> myFoundRefs = new HashSet<>();

                    @Override
                    public boolean process(PsiReference reference) {
                      myFoundRefs.add(reference);
                      return myFoundRefs.size() < 2;
                    }
                  })) return null;
        }
        return new ProblemDescriptor[] {
          manager.createProblemDescriptor(
              psiIdentifier,
              InspectionsBundle.message("boolean.method.is.always.inverted.problem.descriptor"),
              (LocalQuickFix) getQuickFix(null),
              ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
              false)
        };
      }
    }
    return null;
  }