Description:
------------
function not always return data

Reproduce code:
---------------
class a {
  function a1() {
    $a = 5;
    $b = 10;
    $c = $a + $b;
    echo "$c\n";
    return array('a' => $a, 'b' => $b, 'c' => $c);
  }
}
class b {
  function b1() {
    $a = a::a1();
    echo $a['c'];
  }
}
b::b1();
  

Expected result:
----------------
15
15

Actual result:
--------------
15