Can't use the method return value in write context

you can check this by method_exists() function

if (method_exists($this->session->userdata('lastUrl')) && $this->session->userdata('lastUrl') != $this->router->class) {     echo 'new controller';}

php codeigniter uri user-data

isset is a special language construct that can only be used on variables or array keys, not methods. This should have the same functionality:

$this->session->userdata('lastUrl') !== null && ...

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