list-col vs tibble-col?

listcol_vs_tibble_col

library(tibble)
library(tidyr)

x <- tibble(a = 1,
            b = 1:2,
            c = 3:4)

x
#> # A tibble: 2 x 3
#>       a     b     c
#>   <dbl> <int> <int>
#> 1     1     1     3
#> 2     1     2     4

x <- x %>%
  nest(data = c(b, c))

x
#> # A tibble: 1 x 2
#>       a           data
#>   <dbl> <list<df[,2]>>
#> 1     1        [2 × 2]

# cool x has a list-col

y <- tibble(a = 1,
            data = tibble(b = 1:2,
                          c = 3:4))

y
#> # A tibble: 2 x 2
#>       a data$b    $c
#>   <dbl>  <int> <int>
#> 1     1      1     3
#> 2     1      2     4

str(y)
#> Classes 'tbl_df', 'tbl' and 'data.frame':    2 obs. of  2 variables:
#>  $ a   : num  1 1
#>  $ data:Classes 'tbl_df', 'tbl' and 'data.frame':    2 obs. of  2 variables:
#>   ..$ b: int  1 2
#>   ..$ c: int  3 4

# but how do i make y have one