Editing any C++ .cpp file results in the same list of errors for every key stroke entered.

The error appears when a C++ file is edited. This same error returns for every keystroke entered into the file.

CLANG INDEXING: /Users/rebrahimi/Desktop/_optim/primus.cpp
(Creating new index)
Apple clang version 11.0.0 (clang-1100.0.33.17)
Target: x86_64-apple-darwin19.3.0
Thread model: posix
InstalledDir: /Library/Developer/CommandLineTools/usr/bin
ignoring nonexistent directory "../inst/include"
ignoring nonexistent directory "/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/c++/v1"
ignoring nonexistent directory "/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/local/include"
ignoring nonexistent directory "/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/Library/Frameworks"
ignoring duplicate directory "/usr/local/include"
ignoring duplicate directory "/Library/Developer/CommandLineTools/usr/lib/clang/11.0.0/include"
as it is a non-system directory that duplicates a system directory
ignoring duplicate directory "/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include"
#include "..." search starts here:
#include <...> search starts here:
/usr/local/clang7/include/c++/v1
/usr/local/include
/usr/local/clang7/lib/clang/7.0.0/include
/Library/Frameworks/R.framework/Resources/include
/Users/rebrahimi/Library/R/3.6/library/Rcpp/include
/Users/rebrahimi/Library/R/3.6/library/RcppArmadillo/include
/Users/rebrahimi/Desktop/_optim
/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include
/Library/Developer/CommandLineTools/usr/bin/../include/c++/v1
/Library/Developer/CommandLineTools/usr/lib/clang/11.0.0/include
/Library/Developer/CommandLineTools/usr/include
/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/System/Library/Frameworks (framework directory)
End of search list.
/Users/rebrahimi/Library/R/3.6/library/RcppArmadillo/include/RcppArmadillo.h:27:6: error: "The file 'Rcpp.h' should not be included. Please correct to include only 'RcppArmadillo.h'."
TOTAL MEMORY: 138 mb (primus.cpp)
PERFORMANCE 2629 ms (primus.cpp)
CLANG INDEXING: /Users/rebrahimi/Desktop/_optim/primus.cpp
CLANG REMOVE INDEX: /Users/rebrahimi/Desktop/_optim/primus.cpp
(Creating new index)
Apple clang version 11.0.0 (clang-1100.0.33.17)
Target: x86_64-apple-darwin19.3.0
Thread model: posix
InstalledDir: /Library/Developer/CommandLineTools/usr/bin
ignoring nonexistent directory "../inst/include"
ignoring nonexistent directory "/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/c++/v1"
ignoring nonexistent directory "/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/local/include"
ignoring nonexistent directory "/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/Library/Frameworks"
ignoring duplicate directory "/usr/local/include"
ignoring duplicate directory "/Library/Developer/CommandLineTools/usr/lib/clang/11.0.0/include"
as it is a non-system directory that duplicates a system directory
ignoring duplicate directory "/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include"
#include "..." search starts here:
#include <...> search starts here:
/usr/local/clang7/include/c++/v1
/usr/local/include
/usr/local/clang7/lib/clang/7.0.0/include
/Library/Frameworks/R.framework/Resources/include
/Users/rebrahimi/Library/R/3.6/library/Rcpp/include
/Users/rebrahimi/Library/R/3.6/library/RcppArmadillo/include
/Users/rebrahimi/Desktop/_optim
/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include
/Library/Developer/CommandLineTools/usr/bin/../include/c++/v1
/Library/Developer/CommandLineTools/usr/lib/clang/11.0.0/include
/Library/Developer/CommandLineTools/usr/include
/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/System/Library/Frameworks (framework directory)
End of search list.
/Users/rebrahimi/Library/R/3.6/library/RcppArmadillo/include/RcppArmadillo.h:27:6: error: "The file 'Rcpp.h' should not be included. Please correct to include only 'RcppArmadillo.h'."
TOTAL MEMORY: 138 mb (primus.cpp)
PERFORMANCE 2461 ms (primus.cpp)

Additionally, running

.rs.setClangDiagnostics(2)

returns the following:

Attemping to load libclang for x86_64-apple-darwin15.6.0
/Applications/RStudio.app/Contents/MacOS/rsclang/libclang.dylib
(Not Found)
/Library/Developer/CommandLineTools/usr/lib/libclang.dylib
LOADED: 11.0.0

Restarting R session...

Is the error due to libclang.dylib (Not Found)? Everything has been broken after I updated to R version 3.6.2 and RStudio version 1.2.5033 on Mac OS Catalina 10.15.3. Any direction is greatly appreciated.

Do you also see this with RStudio v1.3? Can you provide a reproducible example?