@Nullable
  private static HighlightInfo checkCodeRefInner(GrCodeReferenceElement refElement) {
    if (PsiTreeUtil.getParentOfType(refElement, GroovyDocPsiElement.class) != null) return null;

    PsiElement nameElement = refElement.getReferenceNameElement();
    if (nameElement == null) return null;

    if (isResolvedStaticImport(refElement)) return null;

    GroovyResolveResult resolveResult = refElement.advancedResolve();
    final PsiElement resolved = resolveResult.getElement();

    if (!(refElement.getParent() instanceof GrPackageDefinition) && resolved == null) {
      String message = GroovyBundle.message("cannot.resolve", refElement.getReferenceName());
      HighlightInfo info =
          HighlightInfo.newHighlightInfo(HighlightInfoType.WRONG_REF)
              .range(nameElement)
              .descriptionAndTooltip(message)
              .create();

      // todo implement for nested classes
      HighlightDisplayKey displayKey = HighlightDisplayKey.find(SHORT_NAME);
      registerCreateClassByTypeFix(refElement, info, displayKey);
      registerAddImportFixes(refElement, info, displayKey);
      UnresolvedReferenceQuickFixProvider.registerReferenceFixes(
          refElement, new QuickFixActionRegistrarAdapter(info, displayKey));
      OrderEntryFix.registerFixes(new QuickFixActionRegistrarAdapter(info, displayKey), refElement);

      return info;
    }

    return null;
  }
  @Nullable
  private static HighlightInfo checkRefInner(GrReferenceExpression ref) {
    PsiElement refNameElement = ref.getReferenceNameElement();
    if (refNameElement == null) return null;

    boolean cannotBeDynamic = PsiUtil.isCompileStatic(ref) || isPropertyAccessInStaticMethod(ref);
    GroovyResolveResult resolveResult = getBestResolveResult(ref);

    if (resolveResult.getElement() != null) {
      if (!isInspectionEnabled(ref.getContainingFile(), ref.getProject())) return null;

      if (isStaticOk(resolveResult)) return null;
      String message = GroovyBundle.message("cannot.reference.non.static", ref.getReferenceName());
      return createAnnotationForRef(ref, cannotBeDynamic, message);
    }

    if (ResolveUtil.isKeyOfMap(ref) || isClassReference(ref)) {
      return null;
    }

    if (!cannotBeDynamic) {
      if (!isInspectionEnabled(ref.getContainingFile(), ref.getProject())) return null;
      GrUnresolvedAccessInspection inspection =
          getInstance(ref.getContainingFile(), ref.getProject());

      if (!inspection.myHighlightIfGroovyObjectOverridden && areGroovyObjectMethodsOverridden(ref))
        return null;
      if (!inspection.myHighlightIfMissingMethodsDeclared && areMissingMethodsDeclared(ref))
        return null;

      if (GroovySuppressableInspectionTool.isElementToolSuppressedIn(ref, SHORT_NAME)) return null;
    }

    if (cannotBeDynamic || shouldHighlightAsUnresolved(ref)) {
      HighlightInfo info =
          createAnnotationForRef(
              ref, cannotBeDynamic, GroovyBundle.message("cannot.resolve", ref.getReferenceName()));
      LOG.assertTrue(info != null);

      HighlightDisplayKey displayKey = HighlightDisplayKey.find(SHORT_NAME);
      if (ref.getParent() instanceof GrMethodCall) {
        registerStaticImportFix(ref, info, displayKey);
      } else {
        registerCreateClassByTypeFix(ref, info, displayKey);
        registerAddImportFixes(ref, info, displayKey);
      }

      registerReferenceFixes(ref, info, cannotBeDynamic, displayKey);
      UnresolvedReferenceQuickFixProvider.registerReferenceFixes(
          ref, new QuickFixActionRegistrarAdapter(info, displayKey));
      OrderEntryFix.registerFixes(new QuickFixActionRegistrarAdapter(info, displayKey), ref);
      return info;
    }

    return null;
  }
  private void doCheckRefs(final PsiElement value, final PsiReference[] references, int start) {
    for (int i = start; i < references.length; ++i) {
      PsiReference reference = references[i];
      ProgressManager.checkCanceled();
      if (reference == null) {
        continue;
      }
      if (!hasBadResolve(reference, false)) {
        continue;
      }
      String description = getErrorDescription(reference);

      final int startOffset = reference.getElement().getTextRange().getStartOffset();
      final TextRange referenceRange = reference.getRangeInElement();

      // logging for IDEADEV-29655
      if (referenceRange.getStartOffset() > referenceRange.getEndOffset()) {
        LOG.error(
            "Reference range start offset > end offset:  "
                + reference
                + ", start offset: "
                + referenceRange.getStartOffset()
                + ", end offset: "
                + referenceRange.getEndOffset());
      }

      HighlightInfoType type =
          getTagProblemInfoType(PsiTreeUtil.getParentOfType(value, XmlTag.class));
      if (value instanceof XmlAttributeValue) {
        PsiElement parent = value.getParent();
        if (parent instanceof XmlAttribute) {
          String name = ((XmlAttribute) parent).getName().toLowerCase();
          if (type.getSeverity(null).compareTo(HighlightInfoType.WARNING.getSeverity(null)) > 0
              && name.endsWith("stylename")) {
            type = HighlightInfoType.WARNING;
          } else if (name.equals("href")
              && type.getSeverity(null) == HighlightInfoType.WARNING.getSeverity(null)) {
            continue;
          }
        }
      }
      HighlightInfo info =
          HighlightInfo.createHighlightInfo(
              type,
              startOffset + referenceRange.getStartOffset(),
              startOffset + referenceRange.getEndOffset(),
              description);
      addToResults(info);
      if (reference instanceof QuickFixProvider)
        ((QuickFixProvider) reference).registerQuickfix(info, reference);
      UnresolvedReferenceQuickFixProvider.registerReferenceFixes(
          reference, new QuickFixActionRegistrarImpl(info));
    }
  }