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.
index = index.trim();
  if (index === "*") {
    return Infinity;
  }
  return parseInt(index, 10) || 0;
}
function parseExpression(expr, dotDotAllowed) {
  let match = expr.match(namePattern);
  if (!match) {
    return null;
  }
  let [name] = match;
  const parsed = [
    {
      name,
      cacheName: "." + name,
      index: 0,
      js: null,
      formCalc: null,
      operator: operators.dot,
    },
  ];