Description:
------------
As shown in this example, the elements of $a become a references during "for" cycle, although there are not have any aliases to their values.
If we make a copy ($b=$a) of an array, it becomes an array of references too.
And only if we unset the copy ($b), engine founds that $a elements are not really referenced by another vars.

The same result we can get with foreach($a), (because foreach works with a copy of an array as noted in Bug #24486)

BTW, how can I make a really clean COPY of an array, including all of it elements? And it should be useful to have a method to test if variable have a reference(s).

Reproduce code:
---------------
$a = array(1, 2, 3);

for ($i = 0; $i < count($a); $i++) {
    $x =& $a[$i];
}
$x=&$nowhere;

print "Dump 1 =>"; var_dump($a);
$b=$a;
$b['0']=6; $b['1']=7; $b['2']=8;

print "Dump 2 =>"; var_dump($a);

unset($b); 

print "Dump 3 =>"; var_dump($a);



Expected result:
----------------
I don't know what to expect at all now =)

Before today I should expect all dumps like this:
Dump * =>array(3) {
  [0]=>
  int(1)
  [1]=>
  int(2)
  [2]=>
  int(3)
}


Actual result:
--------------
Dump 1 =>array(3) {
  [0]=>
  &int(1)
  [1]=>
  &int(2)
  [2]=>
  &int(3)
}
Dump 2 =>array(3) {
  [0]=>
  &int(6)
  [1]=>
  &int(7)
  [2]=>
  &int(8)
}
Dump 3 =>array(3) {
  [0]=>
  int(6)
  [1]=>
  int(7)
  [2]=>
  int(8)
}