After updating to R3.5.0 and the latest RStudio I'm having a similar issue (can't install github ggplot2 or even github tidyverse). I get the issue:
devtools::install_github('tidyverse/tidyverse')
Downloading GitHub repo tidyverse/tidyverse@master
from URL https://api.github.com/repos/tidyverse/tidyverse/zipball/master
Installing tidyverse
"C:/PROGRA~1/R/R-35~1.0/bin/x64/R" --no-site-file --no-environ --no-save --no-restore --quiet CMD INSTALL
"C:/Users/emily_ME/AppData/Local/Temp/RtmpQdeo0I/devtools318460497d12/tidyverse-tidyverse-83f6ec3" --library="C:/Users/emily_ME/OneDrive - Market
Economics Limited/Documents/R/win-library/3.5" --install-tests
- installing source package 'tidyverse' ...
** R
** tests
** byte-compile and prepare package for lazy loading
** help
*** installing help indices
converting help for package 'tidyverse'
finding HTML links ... done
tidyverse-package html
tidyverse_conflicts html
tidyverse_deps html
tidyverse_logo html
tidyverse_packages html
tidyverse_update html
*** copying figures
** building package indices
** installing vignettes
** testing if installed package can be loaded
*** arch - i386
Error: package or namespace load failed for 'tidyverse' in library.dynam(lib, package, package.lib):
DLL 'rlang' not found: maybe not installed for this architecture?
Error: loading failed
Execution halted
*** arch - x64
ERROR: loading failed for 'i386' - removing 'C:/Users/emily_ME/OneDrive - Market Economics Limited/Documents/R/win-library/3.5/tidyverse'
In R CMD INSTALL
Installation failed: Command failed (1)
But rlang installed and loads fine, and it's in the library path that shows when I look at .libPaths()
I tried removing and reinstalling rlang and devtools, and tried using the dev versions of both. None of this is working.
I've also tried with Rtools 3.4 and Rtools 3.5. This is super frustrating as I need the dev version of ggplot2 for geom_sf() and other features.