Rule source on GitHub

DowngradeListReferenceAssignmentRector

Convert the list reference assignment to its equivalent PHP 7.2 code

 class SomeClass
 {
     public function run($string)
     {
         $array = [1, 2, 3];
-        list($a, &$b) = $array;
+        list($a) = $array;
+        $b =& $array[1];

-        [&$c, $d, &$e] = $array;
+        [$c, $d, $e] = $array;
+        $c =& $array[0];
+        $e =& $array[2];

-        list(&$a, &$b) = $array;
+        $a =& $array[0];
+        $b =& $array[1];
     }
 }

Configure your rector.php:

<?php

use Rector\Config\RectorConfig;
use Rector\DowngradePhp73\Rector\List_\DowngradeListReferenceAssignmentRector;

return RectorConfig::configure()
    ->withRules([
        DowngradeListReferenceAssignmentRector::class,
    ]);