#128 \not\SomeSymbolRepresentedByAMacro_{subscript} does not work

[Petros Travioli]

Consider the code

\documentclass{article}
\usepackage{unicode-math}%%% If running under lualatex or pdflatex
\newcommand{\pSymbol}{\prec}
\begin{document}
(\not\prec_a) (\not\pSymbol_a)
\end{document}

Under pdflatex (without unicode-math), both outputs coincide, giving an expected "does not precede" symbol with the subscript "a". Under xelatex, they don't; the second one is garbage.

[Petros Travioli]

Possibly a bug in unicode-math rather than in xetex. Needs to be checked.

[Just A. Man]

As of now, the second output looks bad (but is no longer garbage). Running xelatex on

\documentclass{article}
\pagestyle{empty}
\usepackage{unicode-math}
\newcommand{\pSymbol}{\prec}
\begin{document}
\(\not\prec_a\) \(\not\pSymbol_a\)
\end{document}

yields https://i.imgur.com/8SeM0hl.png .