Description:
------------
Depending on context, references can have 3 different behaviours:
1. Reference to element of an array. Element becomes reference automatically until that reference exist. 
1a. Whole array is passed 'by value' and keys of array copy can be modified independently
1b. Element of an array can not be passed 'by value'. It is forced to be passed by reference.
2. Reference to regular variable. Variable does not become reference and can be passed 'by value'

Reproduce code:
---------------
<?php
function bla1($param){ $param['k1']="new!"; }
function bla2($param){ $param="new!";}

$a['k1']='foo';;
echo var_dump($a);
echo "<hr>";
$v=&$a['k1'];
echo var_dump($a);
echo "<hr>";
bla2($a['k1']);
echo var_dump($a);
echo "<hr>";
bla1($a);
echo var_dump($a);
echo "<hr>";
unset($v);
echo var_dump($a);

echo "<hr>";

$k1='foo';
echo var_dump($k1);
echo "<hr>";
$v=&$k1;
echo var_dump($k1);
echo "<hr>";
bla2($k1);
echo var_dump($k1);
echo "<hr>";
unset($v);
echo var_dump($k1);

?>

Expected result:
----------------
any predictable output

Actual result:
--------------
array(1) { ["k1"]=> string(3) "foo" } 
array(1) { ["k1"]=> &string(3) "foo" } 
array(1) { ["k1"]=> &string(3) "foo" } 
array(1) { ["k1"]=> &string(4) "new!" } 
array(1) { ["k1"]=> string(4) "new!" } 
--------------
string(3) "foo" 
string(3) "foo" 
string(3) "foo" 
string(3) "foo"