New WARN on CRAN

[rstub]

CRAN sees a new WARN on some machines, c.f. https://cran.r-project.org/web/checks/check_results_tikzDevice.html:

Version: 0.12.4
Check: re-building of vignette outputs
Result: WARN
    Error(s) in re-building vignettes:
    --- re-building ‘tikzDevice.Rnw’ using knitr
    Error: processing vignette 'tikzDevice.Rnw' failed with diagnostics:
    Running 'texi2dvi' on 'tikzDevice.tex' failed.
    LaTeX errors:
    ! LaTeX Error: Unknown float option `\'.

    See the LaTeX manual or LaTeX Companion for explanation.
    Type H <return> for immediate help.
     ...
    ! Emergency stop.
     ...

    l.238 \begin{figure}[!hb]

    ! ==> Fatal error occurred, no output PDF file produced!
    --- failed re-building ‘tikzDevice.Rnw’

    SUMMARY: processing the following file failed:
     ‘tikzDevice.Rnw’

    Error: Vignette re-building failed.
    Execution halted 

This started a few days ago with R-devel and up-to-date(?) LaTeX.

[rstub]

It looks like a conflict between float.sty and memoir.cls, since the error can be re-produced by using:

\documentclass{memoir}
\usepackage{float}
\begin{document}
\begin{figure}
  abc
\end{figure}
\end{document}