Fatal error: Argument 2 passed to hash_pbkdf2() must be an instance of string, null given in /srv/mediawiki/php-1.24wmf22/includes/password/Pbkdf2Password.php on line 57
Happens when trying to create an account for another person while logged in.
Only happens with HHVM because our version of php5 doesn't have hash_pbkdf2().
Version: unspecified
Severity: normal