I found an issue recently where phpcs (PHP Code Sniffer) was taking ages and times out on a directory. After tracking the issue down to a single file, I found that the line of code causing the issue was a comment.
/**
*
* bla
* @code $params = ['message' => 'Email body', subject' => 'Email subject']
* bla
*/
I have no idea why this happens but took this line of code out and it started working fine.