Prompted for "Selection"

Short summary of the problem:

When I run this code in R, it displays Selection: and I think it’s a prompt but I don’t know what it’s asking for. Output shown below.

library(brms)
library(tidyverse)
library(emdbook)

d <- emdbook::ReedfrogPred
detach(package:emdbook, unload = T)

d %>% glimpse()


(d <-
  d %>%
  mutate(tank = 1:nrow(d)))


b12.1 <-  brm(data = d, family = binomial,
      surv | trials(density) ~ 0 + factor(tank),
      prior(normal(0, 5), class = b),
      iter = 2000, warmup = 500, chains = 4, cores = 4,
      seed = 12, backend="rstan")


> source("R/check.R")
Loading required package: Rcpp
Loading 'brms' package (version 2.13.5). Useful instructions
can be found by typing help('brms'). A more detailed introduction
to the package is available through vignette('brms_overview').

Attaching package: ‘brms’

The following object is masked from ‘package:stats’:

    ar

── Attaching packages ─────────────────────────────────────── tidyverse 1.3.0 ──
✔ ggplot2 3.3.2     ✔ purrr   0.3.4
✔ tibble  3.0.3     ✔ dplyr   1.0.2
✔ tidyr   1.1.1     ✔ stringr 1.4.0
✔ readr   1.3.1     ✔ forcats 0.5.0
── Conflicts ────────────────────────────────────────── tidyverse_conflicts() ──
✖ dplyr::filter() masks stats::filter()
✖ dplyr::lag()    masks stats::lag()
Rows: 48
Columns: 5
$ density  <int> 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, …
$ pred     <fct> no, no, no, no, no, no, no, no, pred, pred, pred, pred, pred…
$ size     <fct> big, big, big, big, small, small, small, small, big, big, bi…
$ surv     <dbl> 9, 10, 7, 10, 9, 9, 10, 9, 4, 9, 7, 6, 7, 5, 9, 9, 24, 23, 2…
$ propsurv <dbl> 0.90, 1.00, 0.70, 1.00, 0.90, 0.90, 1.00, 0.90, 0.40, 0.90, …
Compiling Stan program...
Selection: 



Please also provide the following information in addition to your question:

  • Operating System: nixos unstable
  • brms Version: 2.13.5

This line of code gave me an error:

detach(package:emdbook, unload = T)

but otherwise things ran.

The latest version of brms is 2.14.4. I would first try just upgrading that and Rstan (2.21.2 is the latest there).