(fileBasedMailboxType: StringAdd).self
(fileBasedMailboxType: StringFormat).self
(fileBasedMailboxType: ArrowAssoc[FileBasedMailboxType]).x
(Since version 2.10.0) Use leftOfArrow
instead
(fileBasedMailboxType: Ensuring[FileBasedMailboxType]).x
(Since version 2.10.0) Use resultOfEnsuring
instead