R version 4.0 was released on April 24. I would recommend that anyone who can update R do so. You have to reinstall all you packages, so do
install.packages("rstan", dependencies = TRUE)
And there are a few things that you may have to deal with.
You should uninstall previous versions of R and RTools. Then do,
file.rename(from = "~/.R/Makevars.win", to = "~/.R/Makevars_old") file.remove("~/.R/Makevars") cat("CXX14FLAGS += -mtune=native -march=native -Wno-ignored-attributes -Wno-deprecated-declarations", file = "~/.R/Makevars.win") pkgbuild::has_build_tools(debug = TRUE)
which will download Rtools40.
If that does not work, you can always hard-code the path to the C++ compiler by putting
CXX14 = C:\Rtools\mingw64\bin\g++ -m$(WIN)
in your ~/.R/Makevars.win file.
In R, call
and delete any line that you may have adding something like
/usr/local/clang? to the PATH.
If you use RStudio, there may be problems sampling in parallel from an interactive session, but a workaround is given here
There are no known new issues, but the most common old issue is trying to use a C++ compiler without C++14 support, particularly on RHEL and CentOS which need the RedHat developer toolset.
There are no new issues, but you have to use the GNU toolchain rather than the Oracle one.