# Altered marginpar conflicts with biblatex citation

Consider the MWE below:

\documentclass[10pt,twoside,onecolumn,openright,draft]{memoir}
\usepackage{fontspec}
\usepackage{filecontents}
\usepackage{calc}
\usepackage[french]{babel}
\usepackage{mparhack}
\usepackage{csquotes}
\usepackage[authordate,strict,backend=biber,babel=other]{biblatex-chicago}

%\let\oldmarginpar\marginpar
%\renewcommand\marginpar[1]{\-\oldmarginpar[\raggedleft\footnotesize\hspace{0pt}#1]%
%{\raggedright\footnotesize\hspace{0pt}#1}}

\begin{filecontents}{references.bib}
@book{Thomsen:SL,
author = {Thomsen, Marie-Louise},
title = {The Sumerian Language},
subtitle = {An Introduction to its History and Grammatical Structure},
shorttitle = {Sumerian Language},
shorthand = {SL},
edition = {2},
series = {Mesopotamia Copehagen Studies in Assyriology},
number = {10},
location = {Copenhagen},
date = {1987},
year = {1987}
}
\end{filecontents}
\bibliography{references.bib}

\begin{document}
Texte\marginpar{\cite[§228]{Thomsen:SL}} et encore.
\end{document}


This compiles fine. However, when I uncomment the redefinition of marginpar (which I've used successfully for a few years), I get

./minimal:33: Argument of \blx@citeargs@i has an extra }


Either the redefinition is problematic or else this causes a conflict of some kind with biblatex-chicago.

Any thoughts?

-

You hit a problem if there is ever a ] in the argument as then parsing for the optional argument goes wrong, so you need a {} group to hide the inner ]:
\let\oldmarginpar\marginpar