Use arrow function syntax

Author: gapple

src/Serializer.php

@@ -209,12 +209,13 @@ private static function serializeString(string $value): string
 
     private static function serializeDisplayString(DisplayString $value): string
     {
-        $encodePattern = '/[%"\x00-\x1F\x7F-\xFF]/';
-        $encodeCallback = function ($matches) {
-            return strtolower(rawurlencode($matches[0]));
-        };
-
-        return '%"' . preg_replace_callback($encodePattern, $encodeCallback, (string) $value) . '"';
+        return '%"'
+        . preg_replace_callback(
+            '/[%"\x00-\x1F\x7F-\xFF]/',
+            fn($matches) => strtolower(rawurlencode($matches[0])),
+            (string) $value
+        )
+        . '"';
     }
 
     private static function serializeToken(Token $value): string

tests/ParsingRulesetTrait.php

@@ -15,9 +15,7 @@ public static function parseRulesetDataProvider(): array
     {
         return array_filter(
             static::rulesetDataProvider(),
-            function ($params) {
-                return !empty($params[0]->raw);
-            }
+            fn($params) => !empty($params[0]->raw)
         );
     }
 

tests/SerializingRulesetTrait.php

@@ -15,9 +15,7 @@ public static function serializeRulesetDataProvider(): array
     {
         return array_filter(
             static::rulesetDataProvider(),
-            function ($params) {
-                return !empty($params[0]->expected);
-            }
+            fn($params) => !empty($params[0]->expected)
         );
     }