Description:
------------
When using function date_diff or DateTime::diff, next operation (math, print etc.) 
with variable type float fails. I got results as float(>.J), but only for first 
operation. This issue can persists to next script process(first contains date_diff 
function, next contains operation with float variable)

PHP ver 5.3.1

Test script:
---------------
$a = 141.4;

var_dump($a);

$datetime1 = new DateTime('2009-10-11');
$datetime2 = new DateTime('2009-10-13');
$datetime1->diff($datetime2);

var_dump($a);
var_dump($a);

Expected result:
----------------
float(141.4) float(141.4) float(141.4)

Actual result:
--------------
float(141.4) float(>.J) float(141.4)