Does n_distinct fail with numeric variables?

[emiliotorres]

Dear Sir,
It seems to me that n_distinct() fails with numeric variables.
Best regards
Emilio

library(hflights)
library(dplyr)

## OK
x <- hflights$ArrDelay
class(x) # integer
length(unique(x)) # 464
n_distinct(x) # 464

## WRONG
x <- as.numeric(hflights$ArrDelay)
class(x) # numeric
length(unique(x)) # 464
n_distinct(x) # 4085

sessionInfo()
R version 3.0.2 (2013-09-25)
Platform: x86_64-pc-linux-gnu (64-bit)

locale:
 [1] LC_CTYPE=es_ES.UTF-8       LC_NUMERIC=C              
 [3] LC_TIME=es_ES.UTF-8        LC_COLLATE=es_ES.UTF-8    
 [5] LC_MONETARY=es_ES.UTF-8    LC_MESSAGES=es_ES.UTF-8   
 [7] LC_PAPER=es_ES.UTF-8       LC_NAME=C                 
 [9] LC_ADDRESS=C               LC_TELEPHONE=C            
[11] LC_MEASUREMENT=es_ES.UTF-8 LC_IDENTIFICATION=C       

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

other attached packages:
[1] dplyr_0.1.3  hflights_0.1

loaded via a namespace (and not attached):
[1] assertthat_0.1 Rcpp_0.11.1    tools_3.0.2 
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