public static Set<String> suggestExpressionOfType(
      final PsiClassType type, final PsiLiteralExpression context) {
    PsiVariable[] variables = MacroUtil.getVariablesVisibleAt(context, "");
    Set<String> result = new LinkedHashSet<String>();
    for (PsiVariable var : variables) {
      PsiType varType = var.getType();
      if (type == null || type.isAssignableFrom(varType)) {
        result.add(var.getNameIdentifier().getText());
      }
    }

    PsiExpression[] expressions = MacroUtil.getStandardExpressionsOfType(context, type);
    for (PsiExpression expression : expressions) {
      result.add(expression.getText());
    }
    if (type != null) {
      addAvailableMethodsOfType(type, context, result);
    }
    return result;
  }
  @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;
  }
  @Nullable
  private static GrExpression createDefaultValue(
      GroovyPsiElementFactory factory,
      JavaChangeInfo changeInfo,
      JavaParameterInfo info,
      final GrArgumentList list) {
    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) {
            @Override
            protected boolean check(PsiVariable var, ResolveState state) {
              if (var instanceof PsiField
                  && !resolveHelper.isAccessible((PsiField) var, list, null)) return false;
              if (var instanceof GrVariable
                  && PsiUtil.isLocalVariable(var)
                  && list.getTextRange().getStartOffset() <= var.getTextRange().getStartOffset()) {
                return false;
              }
              if (PsiTreeUtil.isAncestor(var, list, false)) return false;
              final PsiType _type =
                  var instanceof GrVariable ? ((GrVariable) var).getTypeGroovy() : var.getType();
              final PsiType varType = state.get(PsiSubstitutor.KEY).substitute(_type);
              return type.isAssignableFrom(varType);
            }

            @Override
            public boolean execute(@NotNull PsiElement pe, @NotNull ResolveState state) {
              super.execute(pe, state);
              return size() < 2;
            }
          };
      ResolveUtil.treeWalkUp(list, processor, false);
      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>();
          final PsiElementFactory jfactory = JavaPsiFacade.getElementFactory(list.getProject());
          while (containingClass != null) {
            if (type.isAssignableFrom(jfactory.createType(containingClass, PsiSubstitutor.EMPTY))) {
              containingClasses.add(containingClass);
            }
            containingClass = PsiTreeUtil.getParentOfType(containingClass, PsiClass.class);
          }
          if (containingClasses.size() == 1) {
            return factory.createThisExpression(
                containingClasses.contains(parentClass)
                    ? null
                    : containingClasses.iterator().next());
          }
        }
      }
    }

    final String value = info.getDefaultValue();
    return !StringUtil.isEmpty(value) ? factory.createExpressionFromText(value, list) : null;
  }