private static boolean isAppendedRepeatedly(PsiExpression expression) {
      PsiElement parent = expression.getParent();
      while (parent instanceof PsiParenthesizedExpression || parent instanceof PsiPolyadicExpression) {
        parent = parent.getParent();
      }
      if (!(parent instanceof PsiAssignmentExpression assignmentExpression)) {
        return false;
      }
      PsiExpression lhs = PsiUtil.skipParenthesizedExprDown(assignmentExpression.getLExpression());
      if (!(lhs instanceof PsiReferenceExpression referenceExpression)) {
        return false;
      }
      if (assignmentExpression.getOperationTokenType() == JavaTokenType.PLUSEQ) {
        return true;
      }
      final PsiElement element = referenceExpression.resolve();
      if (!(element instanceof PsiVariable)) {
        return false;
      }
      final PsiExpression rhs = assignmentExpression.getRExpression();
      return isAppended(referenceExpression, rhs);
    }
private static boolean isAppendedRepeatedly(PsiExpression expression)