What leads the first element of a printed list to be enclosed with backticks in R v3.5.1?

Question

Recently I updated R to 3.5.1 on may Windows 10 with RStudio v1.1.453. I am interested why the first element of a printed list is now always enclosed in backticks? Even if i

Answer 1

I've encountered the same problem here and have used the workaround:

foo = list('asdf'=NA) # Dummy initial entry
for (listname in c('a','b','c')){
  foo[[listname]] = 1
}

Answer 2

This is a bug in R 3.5.1 only on Windows. It has been fixed in r-devel as of 17 August 2018.