Upgrading magento 2.3.6 to 2.4.5 its running in php8.1

Already run the setup:upgrade command it’s working fine,
but now when I am running the setup:di:compile command, it’s giving the below error message.

Repositories code generation… 1/9 [===>————————]
11% < 1 sec 48.0 MiBsyntax error, unexpected token “”, expecting
variable#0 /home/site/www/vendor/composer/ClassLoader.php(322):
ComposerAutoloadincludeFile()

please provide your suggestion and guidelines.