Configurable

SimplifyUselessVariableRector

Removes useless variable assigns

 function () {
-    $a = true;
-    return $a;
+    return true;
 };

Configure your rector.php:

<?php

use Rector\CodeQuality\Rector\FunctionLike\SimplifyUselessVariableRector;
use Rector\Config\RectorConfig;

return RectorConfig::configure()
    ->withConfiguredRule(SimplifyUselessVariableRector::class, [
        'only_direct_assign' => true,
    ]);

 function () {
     $a = 'Hello, ';
-    $a .= 'World!';

-    return $a;
+    return $a . 'World!';
 };

Configure your rector.php:

<?php

use Rector\CodeQuality\Rector\FunctionLike\SimplifyUselessVariableRector;
use Rector\Config\RectorConfig;

return RectorConfig::configure()
    ->withConfiguredRule(SimplifyUselessVariableRector::class, [
        'only_direct_assign' => false,
    ]);
SETS:  Dead Code