module Base : sig ... endpermissive_cnf query returns a simplified conjunctive normal form that is
more permissive and does not contain negated terms.
There are a couple of special cases to be aware of:
TrueNot is replaced by TrueFalse, and the whole
cnf will be rewritten to [ ] .val arg : t Core.Command.Arg_type.tval matches_message : t ‑> Async_smtp.Smtp_mail_log.Message.t ‑> bool