From Prof Ripley

This is new this version of data.table, but there is much new code in
R-devel, and as this seems to be (NA_INTEGER - 1) I suspect the latter.
Please take a look.

https://www.stats.ox.ac.uk/pub/bdr/memtests/clang-UBSAN/data.table/

(t <- as.ITime("10:45"))
/data/gannet/ripley/R/svn/R-devel/src/main/datetime.c:244:5: runtime
error: signed integer overflow: -2147483648 - 1 cannot be represented in
type 'int'
#0 0x5612872940eb in set_w_yday
/data/gannet/ripley/R/svn/R-devel/src/main/datetime.c:244:5
#1 0x56128729273e in do_balancePOSIXlt
/data/gannet/ripley/R/svn/R-devel/src/main/datetime.c:1477:2