css/css-variables/url-syntax-crash.html

<!doctype html>
<link rel="help" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1935471">
<style>
@property --my-url {
  syntax: "<url> | none";
  inherits: true;
  initial-value: none;
}
:root {
  --my-url: url(blah);
}

* {
  --foo: var(--my-url);
}
</style>
<body>
<script>
  // Get some styling off-thread.
  for (let i = 0; i < 10000; ++i) {
    document.body.appendChild(document.createElement("span"));
  }
</script>