Looks like some deprecated keywords throw errors when searching with the REPL help
help?> abstract
ERROR: Invalid @var syntax `incomplete: premature end of input`.
help?> typealias
ERROR: Invalid @var syntax `incomplete: premature end of input`.
help?> type
ERROR: Invalid @var syntax `incomplete: premature end of input`.
help?> immutable
ERROR: Invalid @var syntax `incomplete: premature end of input`.