Description:
------------
For traditional OOP code it's possible to add an "extra" optional arguments to the method defined somewhere in interface without violating it:

interface TestInterface {
    public function foo();
}
class Test implements TestInterface {
    public function foo($extraArgs=null) {}
}

$obj = new Test;
$obj->foo();

For PHP5.6 variadics can be used nicely for that, but this results in the segfault. See: http://3v4l.org/9bcEJ

Test script:
---------------
interface TestInterface {
    public function foo();
}

class Test implements TestInterface {
    public function foo(...$extraArgs) {

    }
}

$obj = new Test;
$obj->foo();

Expected result:
----------------
Normal termination of script

Actual result:
--------------
Exit code 139, Segmentation fault