fix

Author: samsonasik

rules/Php72/NodeFactory/AnonymousFunctionFactory.php

@@ -82,6 +82,7 @@ public function create(
     public function createAnonymousFunctionFromExpr(Expr $expr): ?Closure
     {
         $stringValue = $this->inlineCodeParser->stringify($expr);
+        $stringValue = $this->normalizeHexBackreferenceExpression($stringValue);
 
         $phpCode = '<?php ' . $stringValue . ';';
         $contentStmts = $this->simplePhpParser->parseString($phpCode);
@@ -125,6 +126,24 @@ public function createAnonymousFunctionFromExpr(Expr $expr): ?Closure
         return $anonymousFunction;
     }
 
+    private function normalizeHexBackreferenceExpression(string $stringValue): string
+    {
+        // Only rewrite when the expression has no quotes, to avoid mutating string literals.
+        if (str_contains($stringValue, "'") || str_contains($stringValue, '"')) {
+            return $stringValue;
+        }
+
+        return Strings::replace(
+            $stringValue,
+            '#0x(?<backreference>\\\d+|\$\d+)#',
+            static function (array $match): string {
+                $backreference = $match['backreference'];
+                $number = ltrim($backreference, '\\$');
+                return 'hexdec($matches[' . $number . '])';
+            }
+        );
+    }
+
     /**
      * @param Param[] $params
      * @return string[]

src/PhpParser/Parser/InlineCodeParser.php

@@ -52,6 +52,11 @@
      */
     private const string BACKREFERENCE_NO_DOUBLE_QUOTE_START_REGEX = '#(?<!")(?<backreference>\$\d+)#';
 
+    /**
+     * @see https://regex101.com/r/8Dk7Qn/1
+     */
+    private const string HEX_BACKREFERENCE_REGEX = '#0x(?<backreference>\\\d+|\$\d+)#';
+
     public function __construct(
         private BetterStandardPrinter $betterStandardPrinter,
         private SimplePhpParser $simplePhpParser,
@@ -81,6 +86,20 @@ public function parseString(string $fileContent): array
     public function stringify(Expr $expr): string
     {
         if ($expr instanceof String_) {
+            if (! str_contains($expr->value, "'") && ! str_contains($expr->value, '"') && StringUtils::isMatch(
+                $expr->value,
+                self::HEX_BACKREFERENCE_REGEX
+            )) {
+                return Strings::replace(
+                    $expr->value,
+                    self::HEX_BACKREFERENCE_REGEX,
+                    static function (array $match): string {
+                        $number = ltrim((string) $match['backreference'], '\\$');
+                        return 'hexdec($matches[' . $number . '])';
+                    }
+                );
+            }
+
             if (! StringUtils::isMatch($expr->value, self::BACKREFERENCE_NO_QUOTE_REGEX)) {
                 return Strings::replace(
                     $expr->value,