@Nullable
 public static List<UnresolvableCollisionUsageInfo> removeConflictUsages(Set<UsageInfo> usages) {
   final List<UnresolvableCollisionUsageInfo> result =
       new ArrayList<UnresolvableCollisionUsageInfo>();
   for (Iterator<UsageInfo> iterator = usages.iterator(); iterator.hasNext(); ) {
     UsageInfo usageInfo = iterator.next();
     if (usageInfo instanceof UnresolvableCollisionUsageInfo) {
       result.add((UnresolvableCollisionUsageInfo) usageInfo);
       iterator.remove();
     }
   }
   return result.isEmpty() ? null : result;
 }
    private void addInaccessibilityDescriptions(
        Set<UsageInfo> usages, MultiMap<PsiElement, String> conflictDescriptions)
        throws IncorrectOperationException {
      PsiMethod method = myChangeInfo.getMethod();
      PsiModifierList modifierList = (PsiModifierList) method.getModifierList().copy();
      VisibilityUtil.setVisibility(modifierList, myChangeInfo.getNewVisibility());

      for (Iterator<UsageInfo> iterator = usages.iterator(); iterator.hasNext(); ) {
        UsageInfo usageInfo = iterator.next();
        PsiElement element = usageInfo.getElement();
        if (element != null) {
          if (element instanceof PsiQualifiedReference) {
            PsiClass accessObjectClass = null;
            PsiElement qualifier = ((PsiQualifiedReference) element).getQualifier();
            if (qualifier instanceof PsiExpression) {
              accessObjectClass =
                  (PsiClass) PsiUtil.getAccessObjectClass((PsiExpression) qualifier).getElement();
            }

            if (!JavaPsiFacade.getInstance(element.getProject())
                .getResolveHelper()
                .isAccessible(method, modifierList, element, accessObjectClass, null)) {
              String message =
                  RefactoringBundle.message(
                      "0.with.1.visibility.is.not.accessible.from.2",
                      RefactoringUIUtil.getDescription(method, true),
                      myChangeInfo.getNewVisibility(),
                      RefactoringUIUtil.getDescription(ConflictsUtil.getContainer(element), true));
              conflictDescriptions.putValue(method, message);
              if (!needToChangeCalls()) {
                iterator.remove();
              }
            }
          }
        }
      }
    }
  @Nullable
  private static PsiExpression createDefaultValue(
      JavaChangeInfo changeInfo,
      final PsiElementFactory factory,
      final JavaParameterInfo info,
      final PsiExpressionList list)
      throws IncorrectOperationException {
    if (info.isUseAnySingleVariable()) {
      final PsiResolveHelper resolveHelper =
          JavaPsiFacade.getInstance(list.getProject()).getResolveHelper();
      final PsiType type = info.getTypeWrapper().getType(changeInfo.getMethod(), list.getManager());
      final VariablesProcessor processor =
          new VariablesProcessor(false) {
            protected boolean check(PsiVariable var, ResolveState state) {
              if (var instanceof PsiField
                  && !resolveHelper.isAccessible((PsiField) var, list, null)) return false;
              if (var instanceof PsiLocalVariable
                  && list.getTextRange().getStartOffset() <= var.getTextRange().getStartOffset())
                return false;
              if (PsiTreeUtil.isAncestor(var, list, false)) return false;
              final PsiType varType = state.get(PsiSubstitutor.KEY).substitute(var.getType());
              return type.isAssignableFrom(varType);
            }

            public boolean execute(PsiElement pe, ResolveState state) {
              super.execute(pe, state);
              return size() < 2;
            }
          };
      PsiScopesUtil.treeWalkUp(processor, list, null);
      if (processor.size() == 1) {
        final PsiVariable result = processor.getResult(0);
        return factory.createExpressionFromText(result.getName(), list);
      }
      if (processor.size() == 0) {
        final PsiClass parentClass = PsiTreeUtil.getParentOfType(list, PsiClass.class);
        if (parentClass != null) {
          PsiClass containingClass = parentClass;
          final Set<PsiClass> containingClasses = new HashSet<PsiClass>();
          while (containingClass != null) {
            if (type.isAssignableFrom(factory.createType(containingClass, PsiSubstitutor.EMPTY))) {
              containingClasses.add(containingClass);
            }
            containingClass = PsiTreeUtil.getParentOfType(containingClass, PsiClass.class);
          }
          if (containingClasses.size() == 1) {
            return RefactoringUtil.createThisExpression(
                parentClass.getManager(),
                containingClasses.contains(parentClass)
                    ? null
                    : containingClasses.iterator().next());
          }
        }
      }
    }
    final PsiCallExpression callExpression =
        PsiTreeUtil.getParentOfType(list, PsiCallExpression.class);
    final String defaultValue = info.getDefaultValue();
    return callExpression != null
        ? info.getValue(callExpression)
        : defaultValue.length() > 0 ? factory.createExpressionFromText(defaultValue, list) : null;
  }