SDK 8.2, 8.3, 8.4: Value not available in all function scopes

(:glance)
class P {
    protected function f() as Void {}

    function g() as Void {
        f(); // Value 'f' not available in all function scopes.
    }
}

class C extends P {
    function initialize() {
        P.initialize();
    }

    protected function f() as Void {}
}

It works in 6.x, 7.x, 8.1.1 and is broken in 8.2.3, 8.3.0, 8.4.0. Strict type checking is enabled.