R CMD check: "..." used in a situation where it does not exist

I think this is bug in R CMD check code.  I get a similar error:

rule: possible error in paste0(...): ... used in a situation where it
  does not exist

for the simple:

rule <- function(..., pad = "-") {
  if (nargs() == 0) {
    title <- ""
  } else {
    title <- paste0(...)
  }
  width <- getOption("width") - nchar(title) - 1
  message(title, " ", paste(rep(pad, width, collapse = "")))
}

where ... clearly does exist.

I skimmed the commits for the last couple of days - the most relevant
would seem to be this one by Michael Lawrence:
https://github.com/wch/r-source/commit/d3a42dabccb23462aa1e0a1edad00450f0a6131c
(but I might've missed others - many of the commit messages are not
terribly explanatory)