vec_c(<empty named>, <empty named>) -> empty unnamed

[romainfrancois]

I would expect vec_c(x, x) to be named here. I believe this is the cause of tidyverse/dplyr#5523

library(vctrs)
x <- rlang::set_names(integer(), character())
vec_c(x, x)
#> integer(0)
vec_c(x)
#> named integer(0)

^{Created on 2020-09-17 by the reprex package (v0.3.0.9001)}

Session info

sessioninfo::session_info()
#> ─ Session info ───────────────────────────────────────────────────────────────
#>  setting  value                       
#>  version  R version 4.0.0 (2020-04-24)
#>  os       macOS Catalina 10.15.6      
#>  system   x86_64, darwin17.0          
#>  ui       X11                         
#>  language (EN)                        
#>  collate  en_US.UTF-8                 
#>  ctype    en_US.UTF-8                 
#>  tz       Europe/Paris                
#>  date     2020-09-17                  
#> 
#> ─ Packages ───────────────────────────────────────────────────────────────────
#>  package     * version    date       lib source                           
#>  assertthat    0.2.1      2019-03-21 [1] CRAN (R 4.0.0)                   
#>  backports     1.1.8      2020-06-17 [1] CRAN (R 4.0.0)                   
#>  cli           2.0.2      2020-02-28 [1] CRAN (R 4.0.0)                   
#>  crayon        1.3.4.9000 2020-07-01 [1] Github (r-lib/crayon@dcf6d44)    
#>  digest        0.6.25     2020-02-23 [1] CRAN (R 4.0.0)                   
#>  ellipsis      0.3.1      2020-05-15 [1] CRAN (R 4.0.1)                   
#>  evaluate      0.14       2019-05-28 [1] CRAN (R 4.0.0)                   
#>  fansi         0.4.1      2020-01-08 [1] CRAN (R 4.0.0)                   
#>  fs            1.4.2      2020-06-30 [1] CRAN (R 4.0.0)                   
#>  glue          1.4.1      2020-05-13 [1] CRAN (R 4.0.0)                   
#>  highr         0.8        2019-03-20 [1] CRAN (R 4.0.0)                   
#>  htmltools     0.5.0      2020-06-16 [1] CRAN (R 4.0.0)                   
#>  knitr         1.29       2020-06-23 [1] CRAN (R 4.0.0)                   
#>  lifecycle     0.2.0      2020-03-06 [1] CRAN (R 4.0.0)                   
#>  magrittr      1.5        2014-11-22 [1] CRAN (R 4.0.0)                   
#>  pillar        1.4.6      2020-07-10 [1] CRAN (R 4.0.0)                   
#>  pkgconfig     2.0.3      2019-09-22 [1] CRAN (R 4.0.0)                   
#>  purrr         0.3.4      2020-04-17 [1] CRAN (R 4.0.0)                   
#>  reprex        0.3.0.9001 2020-06-19 [1] Github (tidyverse/reprex@d898823)
#>  rlang         0.4.7      2020-07-09 [1] CRAN (R 4.0.0)                   
#>  rmarkdown     2.3        2020-06-18 [1] CRAN (R 4.0.0)                   
#>  rstudioapi    0.11       2020-02-07 [1] CRAN (R 4.0.0)                   
#>  sessioninfo   1.1.1      2018-11-05 [1] CRAN (R 4.0.0)                   
#>  stringi       1.4.6      2020-02-17 [1] CRAN (R 4.0.0)                   
#>  stringr       1.4.0      2019-02-10 [1] CRAN (R 4.0.0)                   
#>  styler        1.3.2      2020-02-23 [1] CRAN (R 4.0.0)                   
#>  tibble        3.0.3      2020-07-10 [1] CRAN (R 4.0.0)                   
#>  vctrs       * 0.3.4.9000 2020-09-17 [1] local                            
#>  withr         2.2.0      2020-04-20 [1] CRAN (R 4.0.0)                   
#>  xfun          0.16       2020-07-24 [1] CRAN (R 4.0.2)                   
#>  yaml          2.2.1      2020-02-01 [1] CRAN (R 4.0.0)                   
#> 
#> [1] /Users/romainfrancois/.R/library/4.0
#> [2] /Library/Frameworks/R.framework/Versions/4.0/Resources/library

[lionel-]

Names are not part of the common type so I'm not sure this is the expected behaviour.

[lionel-]

Common types don't have names, but as Davis points out this should still be named since we lazily alloc names for the output if any of the inputs are named.