diff --git a/src/Composer/Autoload/ClassMapGenerator.php b/src/Composer/Autoload/ClassMapGenerator.php
index cc2598596..4b38565eb 100644
--- a/src/Composer/Autoload/ClassMapGenerator.php
+++ b/src/Composer/Autoload/ClassMapGenerator.php
@@ -271,7 +271,7 @@ class ClassMapGenerator
                 if ($name[0] === ':') {
                     // This is an XHP class, https://github.com/facebook/xhp
                     $name = 'xhp'.substr(str_replace(array('-', ':'), array('_', '__'), $name), 1);
-                } elseif ($matches['type'][$i] === 'enum') {
+                } elseif (strtolower($matches['type'][$i]) === 'enum') {
                     // something like:
                     //   enum Foo: int { HERP = '123'; }
                     // The regex above captures the colon, which isn't part of
diff --git a/tests/Composer/Test/Autoload/Fixtures/php8.1/enum_backed.php b/tests/Composer/Test/Autoload/Fixtures/php8.1/enum_backed.php
index bab09e31b..3954c43e8 100644
--- a/tests/Composer/Test/Autoload/Fixtures/php8.1/enum_backed.php
+++ b/tests/Composer/Test/Autoload/Fixtures/php8.1/enum_backed.php
@@ -1,6 +1,6 @@
 <?php
 
-enum RolesBackedEnum:string {
+EnUm RolesBackedEnum:string {
     case Admin = 'Administrator';
     case Guest = 'Guest';
     case Moderator = 'Moderator';