Attach (recommended) or Link to PDF file here:
PDF from #4106, https://mail.gnome.org/archives/evince-list/2013-November/pdfNC0hkVW67a.pdf.

Steps to reproduce the problem:
1. Open the PDF

What is the expected behavior?
![immagine](https://user-images.githubusercontent.com/1616846/121865567-67ca4200-ccfe-11eb-8673-1d6e863fc8d5.png)

What went wrong?
The PDF doesn't load, `TypeError: can't access property Symbol(), match is null` error is logged in the console.
XFAObject,
  XFAObjectArray,
  XmlObject,
} from "./xfa_object.js";
import { warn } from "../../shared/util.js";
const namePattern = /^[^.[]+/;
const indexPattern = /^[^\]]+/;
const operators = {
  dot: 0,
  dotDot: 1,
  dotHash: 2,
  dotBracket: 3,
  dotParen: 4,
};
const shortcuts = new Map([
  ["$data", (root, current) => root.datasets.data],
  ["$template", (root, current) => root.template],
  ["$connectionSet", (root, current) => root.connectionSet],
  ["$form", (root, current) => root.form],
  ["$layout", (root, current) => root.layout],
  ["$host", (root, current) => root.host],
  ["$dataWindow", (root, current) => root.dataWindow],
  ["$event", (root, current) => root.event],
  ["!", (root, current) => root.datasets],
  ["$xfa", (root, current) => root],
  ["xfa", (root, current) => root],
  ["$", (root, current) => current],
]);
const somCache = new WeakMap();
function parseIndex(index) {