use static closure

Author: samsonasik

rector.php

@@ -1,5 +1,6 @@
 <?php
 
+use Rector\CodingStyle\Rector\Closure\StaticClosureRector;
 use Rector\Php81\Rector\FuncCall\NullToStrictStringFuncCallArgRector;
 use Rector\Config\RectorConfig;
 
@@ -11,4 +12,7 @@
     ->withImportNames(removeUnusedImports: true)
     ->withSkip([
         NullToStrictStringFuncCallArgRector::class,
+    ])
+    ->withRules([
+        StaticClosureRector::class,
     ]);

spec/Filter/NamingSpec.php

@@ -4,11 +4,11 @@
 
 use Naming\Filter\Naming;
 
-describe('Naming', function (): void {
+describe('Naming', static function (): void {
 
-    describe('filter()', function (): void {
+    describe('filter()', static function (): void {
 
-        it('set striptags, trim, and strip double space with ucwords with set lower first, upper after apostrophe and hyphen', function (): void {
+        it('set striptags, trim, and strip double space with ucwords with set lower first, upper after apostrophe and hyphen', static function (): void {
 
             $maps = [
                 ''                  => '',

src/Filter/Naming.php

@@ -38,7 +38,7 @@ public function filter(mixed $value): string
         // Ensure the letter after apostrophe/hyphen is uppercase (Unicode-safe)
         $value = preg_replace_callback(
             "/(?<=^|\s)(\p{L}+'?)(\p{Ll})/u",
-            function ($matches) {
+            static function ($matches): string {
                 // only uppercase if it's single-letter prefix like D' or O'
                 if (mb_strlen($matches[1], 'UTF-8') === 2 && str_ends_with($matches[1], "'")) {
                     return $matches[1] . mb_strtoupper($matches[2], 'UTF-8');