append.md
In tidyr: Tidy Messy Data

after must be integer or character

Code
  (expect_error(df_append(df1, df2, after = 1.5)))
Output
  <error/rlang_error>
  Error in `df_append()`:
  ! `after` must be a whole number, not the number 1.5.
  i This is an internal error that was detected in the tidyr package.
    Please report it at <https://github.com/tidyverse/tidyr/issues> with a reprex (<https://https://tidyverse.org/help/>) and the full backtrace.