auctex 11.86 in emacs 24: Don't know how to compile nil

I run emacs 24.2.50.1 and auctex 11.86 on debian stable. When i open a tex file with

``````\$ emacs text.tex
``````

Emacs shows the following line 38 times in the Compile-Log buffer

``````../../../../.emacs.d/elpa/auctex-11.86/font-latex.elc:Error: Don't know how to compile nil
``````

My complete emacs configuration can be found online

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I'm also running Emacs 24.2.50.1 on Debian stable (Squeeze) and I have the same issue. The difference is that I'm using AUCTeX 11.85 from the Debian repository, while you're using 11.86 from the ELPA.

I don't think your configuration is the issue, rather, it seems there is a bug in the `font-latex` package, which is part of AUCTeX, which recent versions of Emacs have stopped silently ignoring. There is a thread on the bug-gnu-emacs mailing list that describes the issue in more detail.

The solution offered there is to upgrade `font-latex`. Unfortunately, the latest version of the `auctex` package in the Debian stable repository does not include the patch for this bug, nor does 11.86, which is the latest version in ELPA. So, I'm not sure there's a solution which will keep either your Debian or ELPA packages consistent.

You might try directly installing a newer version of `auctex` from either Debian `testing` or `unstable`. However, there might be dependency issues, so you could also try apt pinning, which will help resolve the dependencies for you.

My solution was to download the latest version of `font-latex.el`, byte-compile it, and replace the local files:

``````cd /tmp
wget 'http://cvs.savannah.gnu.org/viewvc/*checkout*/auctex/auctex/font-latex.el'
emacs -batch -f batch-byte-compile font-latex.el
sudo cp font-latex.* /usr/share/emacs/24.2.50/site-lisp/auctex/
``````

Note that your path in the final command will be different, since I'm using the version of AUCTeX from the Debian package.

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the compilation fails. Will i need more files? /tmp\$ emacs -batch -f batch-byte-compile font-latex.el [...] In toplevel form: font-latex.el:44:1:Error: Cannot open load file: tex –  Jonas Stein Oct 27 '12 at 16:44
It sounds like it's having trouble locating the file `tex.el`. You might try using `M-x byte-compile-file` from within Emacs instead, to ensure that your `load-path` is complete. Then point it to the `font-latex.el` file you downloaded in `/tmp`. This will produce the `font-latex.elc` file you need. –  Jason Blevins Oct 27 '12 at 17:01
1) Thanks to Jason! BTW, the problem still apparent in emacs 24.3 which has been released ~ 10 days ago. 2) I had the same problem as Jonas, and indeed, byte compiling "inside emacs" was easy and worked. –  Martin Mächler Mar 25 '13 at 9:12