Description:
------------
self and parent as type hint in namespace must be prefixed with '::', but not is possible to use them as class name. So, i'm guessing that shouldn't be necessary the prefix.

Reproduce code:
---------------
<?php
namespace foobar;

class foo {
  // no namespace
  //public function baz(self $a) { }
  // with namespace
  public function baz(::self $a) { }
}

$foo = new foo;
$foo->baz($foo); // Ok!
//$foo->baz(new stdclass); // Error, ok!

Expected result:
----------------
Don't be necessary prefix in self/parent.

Actual result:
--------------
They must be prefixed.