in src/exceptions/AttributeNotSupportedException.hack [15:30]
public function __construct(x\node $that, string $attr) {
parent::__construct(
'Attribute "'.
$attr.
'" is not supported in class '.
'"'.
self::getElementName($that).
'"'.
"\n\n".
$that->__getSourcePositionWithErrorDefaultForNull().
"\n\n".
'Please check for typos in your attribute. If you are creating a new '.
'attribute on this element define it with the "attribute" keyword'.
"\n\n",
);
}