RStudio : version 1.1.419
R version: 3.6.3 (win64)
Rstan: 2.19.3
When I run a stan model from rstan, I get --- twice --- a pop-up saying "Building R package from source requires installation of additional build tools". Even if I answer No to the question whether I want to install additional tools now, the stan program runs (and as far as I can tell, runs correctly). This does not happen under the Rgui, so it seems as if RStudio is failing to realize that something really is installed.
And if I answer Yes to the question, the next time I try to run a stan program from a restarted Rstudio, I get the same pop-ups, so it looks as if nothing is actually installed - or at least nothing that RStudio is aware of.
Has anyone else seen this, and is there fix?