\documentclass[12pt,,a5paper,]{article} \usepackage{amsmath} \usepackage{unicode-math} \renewcommand{\vec}[1] {\overrightarrow{#1}} \begin{document} \section*{} \begin{equation*} -\vec{\nabla} \end{equation*} \end{document} reliably hangs xelatex. For some reason, renewcommand is just breaking things here. Actually, this is more of a question of whether is there a way to install updated versions of latex packages within portage, but it's possible, that the problem is still reproducible upstream. The original issue was \vec not putting the arrows in the right position with STIXGeneral and unicode-math.
well, here it doesnt hang... you'll need to attach the .log file and possibly a gdb run of xelatex. i get a pdf document with two dashes though.
