vars_select behavior with NA args

[MikeBadescu]

I would expect vars_select(c("a", "b"), NA_integer_) to return an error similar to using NA.

library(tidyselect)
vars_select(c("a", "b"), NA)
#> Error: `NA` must evaluate to column positions or names, not a logical vector
vars_select(c("a", "b"), NA_character_)
#> Error: Unknown column `NA`
vars_select(c("a", "b"), NA_integer_)
#>   a   b 
#> "a" "b"

Created on 2018-08-20 by the reprex package (v0.2.0).