No warning for calling protected function from unrelated class

[php4fan]

There's no warning whatsoever for calling a protected method from an unrelated class. In reality this will throw an error at runtime.

Example code:

<?php

class Test1 {
    protected function doWhatever() {

    }
}

class Test2 {
    public function doSomething() {
        $test = new Test1();
        $test->doWhatever(); // <<<<<<<<<<<<<<<<<< this should trigger a warning
    }
}

$test2 = new Test2();
$test2->doSomething();

https://3v4l.org/8iUK4

Fatal error: Uncaught Error: Call to protected method Test1::doWhatever() from scope Test2 in /tmp/preview:12
Stack trace:
#0 /tmp/preview(17): Test2->doSomething()
#1 {main}
  thrown in /tmp/preview on line 12