Error messages regarding vector type check failures can be confusing #2061
Description
From: tidyverse/dplyr#7731
library(dplyr)
#>
#> Attaching package: 'dplyr'
#> The following objects are masked from 'package:stats':
#>
#> filter, lag
#> The following objects are masked from 'package:base':
#>
#> intersect, setdiff, setequal, union
classy_cars <- mtcars
class(classy_cars) <- c(class(classy_cars), "new_class")
class(classy_cars)
#> [1] "data.frame" "new_class"
classy_cars |>
select(mpg, cyl, disp)
#> Error in `eval_select_impl()`:
#> ! `x` must be a vector, not a <data.frame> object.
classy_cars |>
as_tibble() |>
select(mpg, cyl, disp)
#> # A tibble: 32 × 3
#> mpg cyl disp
#> <dbl> <dbl> <dbl>
#> 1 21 6 160
#> 2 21 6 160
#> 3 22.8 4 108
#> 4 21.4 6 258
#> 5 18.7 8 360
#> 6 18.1 6 225
#> 7 14.3 8 360
#> 8 24.4 4 147.
#> 9 22.8 4 141.
#> 10 19.2 6 168.
#> # ℹ 22 more rows
classy_cars |>
mutate(
foo = "foo"
)
#> Error in `mutate()`:
#> ℹ In argument: `foo = "foo"`.
#> Caused by error in `vec_size()`:
#> ! `x` must be a vector, not a <data.frame> object.
classy_cars |>
filter(
cyl > 10
)
#> Error in `vec_slice()`:
#> ! `x` must be a vector, not a <data.frame> object.
classy_cars |>
summarise(
total_mpg = sum(mpg)
)
#> total_mpg
#> 1 642.9Created on 2025-10-08 with reprex v2.1.1
Session info
sessioninfo::session_info()
#> ─ Session info ───────────────────────────────────────────────────────────────
#> setting value
#> version R version 4.4.0 (2024-04-24 ucrt)
#> os Windows 11 x64 (build 22621)
#> system x86_64, mingw32
#> ui RTerm
#> language (EN)
#> collate English_Australia.utf8
#> ctype English_Australia.utf8
#> tz Australia/Brisbane
#> date 2025-10-08
#> pandoc 3.2 @ C:/PROGRA~1/RStudio/RESOUR~1/app/bin/quarto/bin/tools/ (via rmarkdown)
#>
#> ─ Packages ───────────────────────────────────────────────────────────────────
#> package * version date (UTC) lib source
#> cli 3.6.5 2025-04-23 [1] CRAN (R 4.4.3)
#> digest 0.6.37 2024-08-19 [1] CRAN (R 4.4.1)
#> dplyr * 1.1.4.9000 2025-10-08 [1] Github (tidyverse/dplyr@2f9a846)
#> evaluate 1.0.3 2025-01-10 [1] CRAN (R 4.4.2)
#> fastmap 1.2.0 2024-05-15 [1] CRAN (R 4.4.1)
#> fs 1.6.5 2024-10-30 [1] CRAN (R 4.4.2)
#> generics 0.1.4 2025-05-09 [1] CRAN (R 4.4.0)
#> glue 1.8.0 2024-09-30 [1] CRAN (R 4.4.1)
#> htmltools 0.5.8.1 2024-04-04 [1] CRAN (R 4.4.1)
#> knitr 1.49 2024-11-08 [1] CRAN (R 4.4.2)
#> lifecycle 1.0.4 2023-11-07 [1] CRAN (R 4.4.1)
#> magrittr 2.0.4 2025-09-12 [1] CRAN (R 4.4.3)
#> pillar 1.11.1 2025-09-17 [1] CRAN (R 4.4.0)
#> pkgconfig 2.0.3 2019-09-22 [1] CRAN (R 4.4.1)
#> R6 2.6.1 2025-02-15 [1] CRAN (R 4.4.2)
#> reprex 2.1.1 2024-07-06 [1] CRAN (R 4.4.1)
#> rlang 1.1.6.9000 2025-10-08 [1] Github (r-lib/rlang@b351966)
#> rmarkdown 2.29 2024-11-04 [1] CRAN (R 4.4.2)
#> sessioninfo 1.2.2 2021-12-06 [1] CRAN (R 4.4.1)
#> tibble 3.3.0 2025-06-08 [1] CRAN (R 4.4.3)
#> tidyselect 1.2.1 2024-03-11 [1] CRAN (R 4.4.1)
#> vctrs 0.6.5.9000 2025-10-08 [1] Github (r-lib/vctrs@5b539da)
#> withr 3.0.2 2024-10-28 [1] CRAN (R 4.4.0)
#> xfun 0.50 2025-01-07 [1] CRAN (R 4.4.2)
#> yaml 2.3.10 2024-07-26 [1] CRAN (R 4.4.1)
#>
#> [1] C:/Users/msmcba/r_library/user_library_v4.4
#> [2] C:/Program Files/R/R-4.4.0/library
#>
#> ──────────────────────────────────────────────────────────────────────────────The error messages don't really identify the problem or what the user could do to fix it. Confusingly they claim x cannot be a data.frame which is incorrect. Per discussion in the original issue the object needs to be a subclass of a supported atomic type.