Bug report

Trying to access DOMNamedNodeMap::$length throws an error:

Access to an undefined property DOMNamedNodeMap::$length.

However, according to the docs at https://www.php.net/manual/en/class.domnamednodemap.php, $length should be a public read-only property.

Code snippet that reproduces the problem

https://phpstan.org/r/f9ef8226-f1e0-41a1-94e9-995ac9841bd6

Expected output

For the above-linked case, no error should be produced.