2021/11/25/PHP documentation gripe

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The official PHP documentation says:

Covariance allows a child's method to return a more specific type than the return type of its parent's method. Whereas, contravariance allows a parameter type to be less specific in a child method, than that of its parent.

...and then goes on to note that both are supported in #PHP7.4 (which is what I am using).

However:

abstract class cClass1 {
    abstract function GetIt() : mixed;
}
abstract class cClass2 extends cClass1 {
    abstract function GetIt() : object;
}

PHP Fatal error: Declaration of cClass2::GetIt(): object must be compatible with cClass1::GetIt(): mixed in /home/htnet/site/git/ferreteria/base/tests/php2.php on line 6

...and also...

abstract class cClass1 {
    abstract function SetIt($v);
}
abstract class cClass2 extends cClass1 {
    abstract function SetIt(object $v);
}

PHP Fatal error: Declaration of cClass2::SetIt(object $v) must be compatible with cClass1::SetIt($v) in /home/htnet/site/git/ferreteria/base/tests/php2.php on line 6

So, kinda no.

The examples given in the documentation seem to be only about specificity of object types -- so I should be able to do this:

class cClassA {}
class cClassB extends cClassA {}
abstract class cClass1 {
    abstract function SetIt(cClassA $v);
}
abstract class cClass2 extends cClass1 {
    abstract function SetIt(cClassB $v);
}

...but, umm:

PHP Fatal error: Declaration of cClass2::SetIt(cClassB $v) must be compatible with cClass1::SetIt(cClassA $v) in /home/htnet/site/git/ferreteria/base/tests/php2.php on line 8

Looking at the actual example in the docs:

[in progress]