This is one of the times I'm want to see some rationale as to why the bug is with `callable` and not with everything else. You are statically using child's symbol but statically referring to the parent method? If it was dynamic there *might* be a use-case for that but at least directly as written I don't see the value. Is there some use I'm missing?

I can't see any real use case for this. However, my point is that type-hinting against a callable should ensure that the argument is a function/method, so there is a problem in the pseudo-type checking mechanism indeed.

> which is a perfectly valid form of callable.

Other than, "it kind of works some of the time", what's the justification for saying that it's a valid form of callable? i.e. is it in the manual anywhere?

From manual: http://php.net/manual/en/language.types.callable.php


// Type 5: Relative static class method call (As of PHP 5.3.0)
class A {
    public static function who() {
        echo "A\n";
    }
}

class B extends A {
    public static function who() {
        echo "B\n";
    }
}

call_user_func(array('B', 'parent::who')); // A

Also note that not only `parent::` is_callable() , but actually
any parent class of the class designated by the first array
element. E.g. <https://3v4l.org/QULq6>.  In my opionion that's
rather dubious, but we may not be able to change this for BC
reasons.

https://wiki.php.net/rfc/deprecate_partially_supported_callables would resolve this inconsistency by dropping support.