Came across a similar crash today. In RulesListTable.class.php, line 49 we have
$rule = new (AutomaticProductCategories::instance()->ruleClass())();
… which my (old) PHP 7.3 does not seem to like. If I change this to
$_classname=AutomaticProductCategories::instance()->ruleClass();
$rule=new $_classname();
… it works