Description:
------------
Each closure instance should have its own set of static variables. This works perfectly with non-generator closures (replace yield by return array in the test script), but not with generator closures (run the test script), where static variables seem to behave like a normal local variables.


Test script:
---------------
<?php

function new_closure_gen() {
  return function() { 
    static $foo = 0; 
    //return array(++$foo);
    yield ++$foo; 
  };
}

$closure1 = new_closure_gen();
$closure2 = new_closure_gen();

$gen1 = $closure1();
$gen2 = $closure1();
$gen3 = $closure2();

foreach (array($gen1, $gen2, $gen3) as $gen) {
  foreach ($gen as $val) {
    print "$val\n";
  }
}


Expected result:
----------------
1
2
1


Actual result:
--------------
1
1
1