RequiredUseCheck/InvalidRequiredUse
  InvalidRequiredUse: version 0: failed parsing REQUIRED_USE: '|| ( )' is unparseable
  InvalidRequiredUse: version 1: failed parsing REQUIRED_USE: '?' is unparseable: flagged token- ?
  InvalidRequiredUse: version 2: failed parsing REQUIRED_USE: 'required?' is unparseable: flagged token- required?
