Description:
------------
I noticed a slight change in the order some instructions   
get executed.   
  
The execution order of instructions for a code like 
$result[$base]=$base++;  
differs from PHP 5.1 to previous versions so that the 
$result variable also has different values as follows:  
   
PHP 4.3.10   : array(1) { [0]=> int(0) }     
PHP 5.0.3    : array(1) { [0]=> int(0) }     
PHP 5.1.0b3  : array(1) { [1]=> int(0) }    
PHP 5.1.0RC1 : array(1) { [1]=> int(0) }    

Reproduce code:
---------------
$base=0;
$result[$base]=$base++;
var_dump($result);


Expected result:
----------------
To keep compatibility with PHP 4.x and 5.0.x:   
   
array(1) { [0]=> int(0) }     

Actual result:
--------------
array(1) { [1]=> int(0) }