LaTeX.org

Here is a minimal working example. Most of it constist of latexdiff's untouched preamble additions:

%\RequirePackage[l2tabu]{nag}

\documentclass[11pt]{article}
\usepackage[backend=biber,bibencoding=utf8,style=numeric-comp]{biblatex}
\addbibresource{literature.bib}
%\usepackage{hyperref}

%DIF ...

Okay, we'll see if the developers can get wind of these two things and resolve them. Thanks for investigating!

But I use (an updated) MikTeX 2.9
(Edit: I meant 2.9 sorry)

Also, the conflict (in relation to the warning message) isn't between etoolbox and breqn; but between biblatex and breqn. With etoolbox the warning actually disappears.

Can you reproduce the errors resulting from using minipage, which ...

Exactly. There are many warnings that breqn is incompatible with a lot of other packages on other forums like TeX.sx.
I wonder if the minipage error was found ;)


I wouldn't think so: two of the maintainers, Will Robertson and Joseph Wright, are part of the LaTeX3 development team so they ...

breqn fiddles with catcodes and also uses the latex3 -syntax, which is still officially experimental (though it is considered inofficially as stable).
I am not experienced with LaTeX3 or catcodes.

If the maintainers do not answer, maybe someone else can provide a fix hack.
It seems eigher ...

Okay, since you seem interested in solving this, I tracked it down. ;)

It's a combination of LuaTeX compilation with the breqn , mathtools and unicode-math packages, and the minipage environment. These give an error:

Undefined control sequence \end{minipage}

See the following example ...

So I discovered yet another incompatibility with breqn : LuaTeX. My document doesn't compile with it, while it does with XeTeX. I don't know what's the reason this time. Maybe I'll hunt it down later. For now, this whole exercise in trying to automatically break equations has cost me more time than ...

While shifting things around in my preamble I discovered something funny. When you load the package etoolbox first then the warning disappears again:

\documentclass{article}
\usepackage{etoolbox}
\usepackage{breqn}
\usepackage[backend=biber]{biblatex}

\begin{document}
...
\end{document}

I guess ...

When I load the breqn package before the biblatex package it gives the following warning:

Package etoolbox Warning: Patching '\end' failed!
(etoolbox) '\AfterEndEnvironment' will not work.

This is using an updated MikTeX 1.9 and the driver used doesn't matter. Here's a small example ...

Forcing it to use Unicode works. The dash even shows up correctly in the pdf file. I think you actually solved the problem! (Even though we don't understand exactly what's going on. )