Description:
------------
I try to do an array access wrapped with empty on a constant array and a notice is thrown. I expected that empty would simply return false in the case the key is not found.

Test script:
---------------
<?php
class Test
{
  const FOO = ["a" => 0, "b" => 1, "b" => 2, "d" => 3];    

  public function getTest()
  {
    $a = ["a" => 0, "b" => 1, "b" => 2, "d" => 3];
    var_dump(empty($a["not_found"]));

    $b = self::FOO;
    var_dump(empty($b["not_found"]));

    var_dump(empty(self::FOO["not_found"]));
  }
}


$a = new Test();
$a->getTest();

Expected result:
----------------
bool(true)
bool(true)
bool(true)

Actual result:
--------------
bool(true)
bool(true)
<br />
<b>Notice</b>:  Undefined index: vsqsc in <b>[...][...]</b> on line <b>9</b><br />
bool(true)