DOMNode::C14N when not using an $xpath doesn't work correctly with PHPStan on PHP 7.x. https://phpstan.org/r/5a2df335-43be-4ec2-8f64-6243d3ca60b9 This reports: Parameter #3 $xpath of method DOMNode::C14N() expects array, null given. However, the null is allowed there: ``` php --rf DOMNode::C14N Method [ <internal:dom> public method C14N ] { - Parameters [4] { Parameter #0 [ <optional> $exclusive ] Parameter #1 [ <optional> $with_comments ] Parameter #2 [ <optional> array or NULL $xpath ] Parameter #3 [ <optional> array or NULL $ns_prefixes ] } } ```