Description:
------------
Could not catch exception throw from error_handler function.
I couldn't do it only in this situation, other works well.
order of errors: 
  NOTICE: Undefined variable ...
  FATAL: Class name must be a ...

Reproduce code:
---------------
<?php
error_reporting( E_ALL );
set_error_handler( 'error_handler' );

function error_handler( $errno, $errstr, $errfile, $errline )
{
    echo "($errno) $errstr\n";
    throw new Exception( $errstr, $errno );
}

class someClass { /*....*/ }

unset( $test );

$o = new $test;
?>

Expected result:
----------------
Uncaughted exception message ... with trace.

Actual result:
--------------
non-readable core dump or smth like this.