Rstan won't compile

Summary:

Rstan won’t compile. Rstan worked fine until I upgraded to R4.0.1 and RTools4.0.

Description:

Here’s the error message I get when trying to compile:

Error in file(con, "r") : cannot open the connection
In addition: Warning messages:
1: In system(cmd, intern = !verbose) :
running command 'C:/PROGRA~1/R/R-4.0.1/bin/x64/R CMD SHLIB file2cd4445c123a.cpp 2> file2cd4445c123a.cpp.err.txt' had status 1
2: In file(con, "r") :
cannot open file 'file2cd4445c123a.cpp.err.txt': No such file or directory
Error in sink(type = "output") : invalid connection
Error in sink(type = "output") : invalid connection

Reproducible Steps:

See attached .

If you have a reproducible example, please include it.

Current Output:

If applicable, any relevant output from RStan.

Expected Output:

See error message above.

RStan Version:

rstan_2.19.3
StanHeaders_2.21.0-5

R Version:

R version 4.0.1 (2020-06-06)

Operating System:

Platform: x86_64-w64-mingw32/x64 (64-bit)
Running under: Windows 10 x64 (build 18363)

Simple_Regression1.zip

Start by reproducing the failure with Simple_Regression1.zip using RStan 2.19.3, StanHeaders 2.21.0-5, R 4.0.1, RTools4.0, and Windows 10. Inspect the R CMD SHLIB invocation and the generated compiler output; done means identifying the compatibility or build cause and confirming that the example compiles successfully.