Error in re-building vignettes:
  ...
You are recommended to install the tinytex package to build PDF.FALSE
Latexmk: This is Latexmk, John Collins, 1 January 2015, version: 4.41.
Rule 'pdflatex': File changes, etc:
   Changed files, or newly in use since previous run(s):
      'RcppClassic-intro.aux'
   Non-existent destination files:
      'RcppClassic-intro.pdf'
------------
Run number 1 of rule 'pdflatex'
------------
------------
Running 'pdflatex  -halt-on-error -interaction=batchmode -recorder  "RcppClassic-intro.tex"'
------------
Latexmk: applying rule 'pdflatex'...
This is pdfTeX, Version 3.14159265-2.6-1.40.19 (TeX Live 2018/Debian) (preloaded format=pdflatex)
 restricted \write18 enabled.
entering extended mode
Latexmk: List of undefined refs and citations:
  Citation `CRAN:Rcpp' on page 1 undefined on input line 63
  Citation `Eddelbuettel:2013:Rcpp' on page 1 undefined on input line 63
  Citation `PeerJ:Rcpp' on page 1 undefined on input line 63
  Reference `mdf@pagelabel-1' on page 1 undefined on input line 94
  Reference `mdf@pagelabel-2' on page 1 undefined on input line 108
  Reference `mdf@pagelabel-3' on page 1 undefined on input line 127
  Reference `mdf@pagelabel-4' on page 1 undefined on input line 139
  Reference `mdf@pagelabel-5' on page 1 undefined on input line 164
  Reference `mdf@pagelabel-6' on page 1 undefined on input line 172
Latexmk: Summary of warnings:
  Latex failed to resolve 6 reference(s)
  Latex failed to resolve 4 citation(s)
Collected error summary (may duplicate other messages):
  pdflatex: Command for 'pdflatex' gave return code 256
Latexmk: Use the -f option to force complete processing,
 unless error was exceeding maximum runs of latex/pdflatex.
Latexmk: Errors, so I did not complete making targets

Latexmk, John Collins, 1 January 2015. Version 4.41
Warning: Your latexmk version seems to be too low. You may need to update the latexmk package or your LaTeX distribution.
! LaTeX Error: Lonely \item--perhaps a missing list environment.

Error: processing vignette ‘RcppClassic-intro.Rmd’ failed with diagnostics:
Failed to compile RcppClassic-intro.tex. See RcppClassic-intro.log for more info.
Execution halted