Submitted by: brodie gaslam; Assigned to: Arun ; R-Forge link
Right now, it's perfectly possible to create POSIXlt columns in data tables, leading to understandable confusion when bizarre behavior ensues. To the extent this is not supported, constructors for data table should throw errors or warning. References:
http://stackoverflow.com/questions/21487614/error-creating-r-data-table-with-date-time-posixlt
Also, another one that I can't find now where there were weird errors when attempting to head or print a data table with such columns.