Subsetting fails with integer64 keys

[vspinu]

With git head:

require(data.table)
require(bit64)
tdf <- data.table(id = as.integer64(1:3), a = c("a", "b", "c"), key = "id")
# str(tdf)
# Classes ‘data.table’ and 'data.frame':    3 obs. of  2 variables:
#  $ id:Class 'integer64'  num [1:3] 4.94e-324 9.88e-324 1.48e-323
#  $ a : chr  "a" "b" "c"
#  - attr(*, "sorted")= chr "id"
#  - attr(*, ".internal.selfref")=<externalptr> 
tdf[.(2)]
# Empty data.table (0 rows) of 2 cols: id,a
tdf[, id := as.numeric(id)]
setkey(tdf, id)
tdf[.(2)]
#    id a
#1:  2 b

sessionInfo()
# R version 3.1.2 (2014-10-31)
# Platform: x86_64-redhat-linux-gnu (64-bit)

# locale:
#  [1] LC_CTYPE=en_US.utf8       LC_NUMERIC=C              LC_TIME=en_US.utf8        LC_COLLATE=en_US.utf8    
#  [5] LC_MONETARY=en_US.utf8    LC_MESSAGES=en_US.utf8    LC_PAPER=en_US.utf8       LC_NAME=C                
#  [9] LC_ADDRESS=C              LC_TELEPHONE=C            LC_MEASUREMENT=en_US.utf8 LC_IDENTIFICATION=C      

# attached base packages:
# [1] parallel  splines   stats     graphics  grDevices utils     datasets  methods   base     

# other attached packages:
#  [1] plotmo_2.2.1         gbm_2.1-06           lattice_0.20-29      survival_2.37-7      foreach_1.4.2       
#  [6] dplyr_0.4.1          plyr_1.8.1           Rcpp_0.11.3          lubridate_1.4.0.9000 bit64_0.9-4         
# [11] bit_1.1-12           ggplot2_1.0.0.99     data.table_1.9.5     devtools_1.7.0      

# loaded via a namespace (and not attached):
#  [1] assertthat_0.1   bitops_1.0-6     chron_2.3-45     codetools_0.2-9  colorspace_1.2-4 compiler_3.1.2  
#  [7] DBI_0.3.1        digest_0.6.8     evaluate_0.5.5   formatR_1.0      grid_3.1.2       gtable_0.1.2    
# [13] httr_0.6.1       iterators_1.0.7  knitr_1.9.1      labeling_0.3     magrittr_1.5     MASS_7.3-35     
# [19] munsell_0.4.2    proto_0.3-10     RCurl_1.95-4.5   reshape2_1.4.1   scales_0.2.4     stringr_0.6.2   
# [25] tools_3.1.2     

[vspinu]

The problem has to do with the type. The following works:

tdf <- data.table(id = as.integer64(1:3), a = c("a", "b", "c"), key = "id")
> tdf <- data.table(id = as.integer64(1:3), a = c("a", "b", "c"), key = "id")
> tdf[.(as.integer64(2))]
   id a
1:  2 b

Which makes it quite inconvenient to work with. I hope there is an easy fix for this.