Pattern: Use of !!
Issue: -
This rule checks for uses of double negation (!!) to convert something
to a boolean value. As this is both cryptic and usually redundant, it
should be avoided.
Please note that when something is a boolean value !!something and !something.nil? are not the same thing. As you're unlikely to write code that can accept values of any type this is rarely a problem in practice.
# bad
!!something
# good
!something.nil?