Bug report

Accessing the public properties $f, $days and $invert of a class that extends DateInterval throws this error:

Access to private property $f of parent class DateInterval.

However, these properties have always been publicly accessible.

https://www.php.net/manual/en/class.dateinterval.php

Code snippet that reproduces the problem

https://3v4l.org/MkELZ

class NewInterval extends DateInterval
{
}

$i = new NewInterval('P1D');
$i->f = 0.1;
var_dump($i);

Expected output

I don't see any reason this should be considered private.

I am not sure where DateInterval properties are documented. There is a date.stub file, but that was added recently. Are properties defaulted to private or is there an actual mapping that is marking them private?