Description:
------------
I've only just stated using the extension, but I'd have thought that the following would have raised warnings.

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

    $tainted = '1-Evil';
    taint($tainted);
    
    preg_match('/^1-(.*)/', $tainted, $matches);
    
    echo $matches[1] . "\n";
    echo str_ireplace('1-', '2-', $tainted) . "\n";
    echo preg_replace('/^1-/', '2-', $tainted) . "\n";

?>

Expected result:
----------------
Evil
2-Evil
2-Evil

Actual result:
--------------
<br />
<b>Warning</b>:  main() [echo]: Attempt to echo a string that might be tainted in <b>./index.php</b> on line <b>8</b><br />
1-Evil
<br />
<b>Warning</b>:  main() [echo]: Attempt to echo a string that might be tainted in <b>./index.php</b> on line <b>9</b><br />
2-Evil
<br />
<b>Warning</b>:  main() [echo]: Attempt to echo a string that might be tainted in <b>./index.php</b> on line <b>10</b><br />
2-Evil