protected boolean checkErrors(@NotNull PsiClass targetClass) {
    String fieldName = settings.getName();
    String errorString = check(targetClass, fieldName);

    if (errorString != null) {
      String message = RefactoringBundle.getCannotRefactorMessage(errorString);
      CommonRefactoringUtil
        .showErrorMessage(GroovyBundle.message("introduce.constant.title"), message, HelpID.INTRODUCE_CONSTANT, context.getProject());
      return true;
    }

    PsiField oldField = targetClass.findFieldByName(fieldName, true);
    if (oldField != null) {
      String message = RefactoringBundle.message("field.exists", fieldName, oldField.getContainingClass().getQualifiedName());
      int answer = Messages
        .showYesNoDialog(context.getProject(), message, GroovyBundle.message("introduce.constant.title"), Messages.getWarningIcon());
      if (answer != Messages.YES) {
        return true;
      }
    }
    return false;
  }
protected boolean checkErrors(@NotNull PsiClass targetClass)