I think both should be identical. Probably there's a similar problem with [[<- . Happy to send a PR.
library(vctrs)
xx <- new_rcrd(list(x = 1:3, a = list(1, 2:3, 4:6)))
field(xx[3], "a")
#> [[1]]
#> [1] 4 5 6
field(xx[[3]], "a")
#> [1] 4 5 6
Created on 2020-08-03 by the reprex package (v0.3.0)
I think both should be identical. Probably there's a similar problem with
[[<-. Happy to send a PR.Created on 2020-08-03 by the reprex package (v0.3.0)