ArraySpreadInsteadOfArrayMergeRector

Find another rule

Change array_merge() to spread operator

 class SomeClass
 {
     public function run($iter1, $iter2)
     {
-        $values = array_merge(iterator_to_array($iter1), iterator_to_array($iter2));
+        $values = [...$iter1, ...$iter2];

         // Or to generalize to all iterables
-        $anotherValues = array_merge(
-            is_array($iter1) ? $iter1 : iterator_to_array($iter1),
-            is_array($iter2) ? $iter2 : iterator_to_array($iter2)
-        );
+        $anotherValues = [...$iter1, ...$iter2];
     }
 }

Configure your rector.php:

<?php

use Rector\CodingStyle\Rector\FuncCall\ArraySpreadInsteadOfArrayMergeRector;
use Rector\Config\RectorConfig;

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