address new warning in R-devel (#4986)
address new warning in R-devel (#4986)


Rdatatable/data.table,vlulla/data.table,Rdatatable/data.table,jangorecki/data.table,vlulla/data.table,jangorecki/data.table,Rdatatable/data.table,jangorecki/data.table,Rdatatable/data.table,vlulla/data.table,vlulla/data.table,jangorecki/data.table