Description:
------------
class_exists with return appears to avoid setting a variable after a class definition.

Avoiding the return  inside the if block like work as expected:
<?
if(!class_exists('newclass')){
 class newclass(){
 }
}
$var_newclass = "newclass ok\n";
?>

But I couldn't find anything in the documentation explaining this behaviour.

Reproduce code:
---------------
"class.php"
<?
if(class_exists('newclass')){
    return;
}
class newclass{
    function newclass(){
        echo "hi\n";
    }
}
$var_newclass = "newclass ok\n";
?>

"test.php"
<?
include("class.php");
new newclass;
echo $var_newclass;
?>

Expected result:
----------------
hi
newclass ok


Actual result:
--------------
hi