Description:
------------
extract() turns array elements back to references after they were once referenced and despite the reference was removed.
Tested on PHP 5.6.12 (works as expected), 7.0b3 (buggy) and git rev 2366a070c8 (buggy).


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

$array = ['key' => 'value'];

// create a reference to an element of the array
$ref = & $array['key'];

// make sure array element is a reference
var_dump($array);

// remove the $ref reference
unset($ref);

// make sure array elements are no longer references
var_dump($array);

extract($array);

// make sure array elements are still no references
var_dump($array);


Expected result:
----------------
array(1) {
  ["key"]=>
  &string(5) "value"
}
array(1) {
  ["key"]=>
  string(5) "value"
}
array(1) {
  ["key"]=>
  string(5) "value"
}


Actual result:
--------------
array(1) {
  ["key"]=>
  &string(5) "value"
}
array(1) {
  ["key"]=>
  string(5) "value"
}
array(1) {
  ["key"]=>
  &string(5) "value"   <=== reference again
}