list() cannot split string directly anymore, use str_split()
-list($foo) = "string";
+list($foo) = str_split("string");Configure your rector.php:
<?php
use Rector\Config\RectorConfig;
use Rector\Php70\Rector\Assign\ListSplitStringRector;
return RectorConfig::configure()
->withRules([
ListSplitStringRector::class,
]);
