Problem with breqn and mathtools

[Volker-Weissmann]

The following code does not compile:

\documentclass{article}
\usepackage{breqn}
\usepackage{mathtools}
\begin{document}\end{document}

but the following code compiles just fine

\documentclass{article}
\usepackage{mathtools}
\usepackage{breqn}
\begin{document}\end{document}

It would be a nice improvement, if you could either make sure that the first version also compiles or outputs an error message that says that you should switch the order of the usepackages.

[FrankMittelbach]

see also https://github.com/latex3/latex2e/issues/209 (closed there)

[wspr]

Ah, this isn't anything to do with mathtools; here is a further reduced minimal example:

\documentclass{article} \usepackage{breqn} \AtBeginDocument{\RequirePackage{graphicx}} \begin{document}\end{document}

I guess I could fix this just by loading graphicx inside of breqn!