Missing "in_list" function from from_validation library

Hi, the function in_list is missing from the form_validation library and if you use it as a rule it generates "Unable to access an error message corresponding to your field" + it doesn't do anything.
Hope you solve this problem, thanks!

Update: the problem in gone in 3.0 RC2

It's not a problem gone in RC2, it's a feature that never existed prior to RC2.