Updated R to 3.6 and all hell broke loose

Summary:

Updated R and Rstudio, and all hell broke loose

Description:

I've been running the rethinking package, which uses rstan, for about 6 months - no problem. I updated R today, and all of a sudden things have gone haywire.

I uninstalled and re-installed rstan (and all other packages, for that matter), including updating Rtools. No luck. When I try to run the schools example directly from the Rstan "getting started" page, I get the error listed below

The C++ toolchain passes the test
I have also tried disabling the C++ toolchain configuration (which is noted to sometimes cause problems). No luck. Exact same issue.

I have de-installed and re-installed from scratch (R, then Rstan, then other toolboxes), but still no luck.

Any advice would be GREATLY appreciated. BTW - I'm just an ordinary scientist, not a developer or c-scientist ...so I would appreciate advice being "dummed down" as much as possible. TIA

Reproducible Steps:

Followed the steps on the Get Started page EXACTLY

Current Output:

Error in compileCode(f, code, language = language, verbose = verbose) :
Compilation ERROR, function(s)/method(s) not created! In file included from C:/Users/schwa/Documents/R/win-library/3.6/BH/include/boost/random/detail/integer_log2.hpp:19:0,
from C:/Users/schwa/Documents/R/win-library/3.6/BH/include/boost/random/detail/int_float_pair.hpp:26,
from C:/Users/schwa/Documents/R/win-library/3.6/BH/include/boost/random/exponential_distribution.hpp:27,
from C:/Users/schwa/Documents/R/win-library/3.6/BH/include/boost/random/gamma_distribution.hpp:25,
from C:/Users/schwa/Documents/R/win-library/3.6/StanHeaders/include/stan/math/prim/mat/prob/dirichlet_rng.hpp:5,
from C:/Users/schwa/Documents/R/win-library/3.6/StanHeaders/include/stan/math/prim/mat.hpp:276,
from C:/Users/schwa/Documents/R/win-library/3.6/StanHeaders/include/stan/math/rev/mat.hpp:12,
from C:/Users/schwa/Documents/R/win-library/3.6/StanHeaders/include/stan/math.hpp:4,

Error in sink(type = "output") : invalid connection

Expected Output:

RStan Version:

The version of RStan you are running (e.g., from packageVersion("rstan"))

R Version:

2.18.12

Operating System:

Windows 10

Commencez par reproduire l’exemple schools de la page RStan Get Started sous Windows 10, en utilisant les versions indiquées de R, RStan, Rtools et RStudio. Examinez la sortie du compilateur qui commence par les chemins de Boost et StanHeaders, puis comparez le résultat avec la configuration documentée de la toolchain. La tâche est terminée lorsque la divergence de l’environnement ou l’échec de compilation est identifié et qu’un exemple fonctionnel est confirmé.