instanceof non funziona

[zacca94]

index.php

<?php
/** 
 * Set exception handler 
 */
set_exception_handler(array('system\bootstrap\Blind', 'exceptionHandler'));

/** 
 * Set php error handler 
 */
set_error_handler(array('system\bootstrap\Blind', 'errorHandler'), E_ALL);

// [...]

    public static final function exceptionHandler(\Exception $e) {            
      // var_dump($e);        
      if ($e instanceof IException) { 
        $e->show(); 
      }
    }
  
    public static final function errorHandler($errorNo, $message, $filename, $lineNo) {            
      throw new BlindException($errorNo, $message, $filename, $lineNo);
    }

includes/Error/BaseErrorHandler.php

<?php
namespace Error;

class BaseErrorHandler extends \Exception {
  // [...]
}

includes/Error/BlindException.php

<?php
namespace Error;

class BlindException extends BaseErrorHandler implements IException {
  public function show() {
    die("show");
  }
}

includes/Error/IException.php

<?php
namespace error;

interface IException {  
  public function show();
}

Perchè l'if ($e instanceof IException) ​non viene eseguito?