Asterisk (*) in listings environment becomes lower

[stone-zeng]

Consider the following code:

\documentclass{article}
\usepackage{listings,fontspec}

\newfontfamily\CodeFont{Source Code Pro}
\setmonofont{Source Code Pro}

\begin{document}

{CodeFont: \CodeFont emph*}

{ttfamily: \ttfamily emph*}

\begin{lstlisting}[basicstyle=\CodeFont]
\CodeFont:
\emph*{hello}
\end{lstlisting}

\begin{lstlisting}[basicstyle=\ttfamily]
\ttfamily:
\emph*{hello}
\end{lstlisting}

\end{document}

The result is

Notice that the asterisk is lower when using \CodeFont, but it's normal for \ttfamily.

I have tried other fonts. This issue appears when using Fira Code, Libertinus Mono etc, but doesn't show for CMU Typewriter.

Another test for Lucida Sans Unicode, however, shows that the asterisk (U+002A) becomes math asterisk (U+2217) improperly:

[qinglee]

AFAIK this issue has nothing to do with fontspec. It is the black magic of the listings package.

We can see the following code fragment in listings.sty:

\lst@CCPutMacro
    ...
    \lst@ProcessOther {"2A}{\lst@ttfamily*\textasteriskcentered}
    ...
    \@empty\z@\@empty
\def\lst@ttfamily#1#2{\ifx\f@family\ttdefault#1\relax\else#2\fi}

The definition of \textasteriskcentered is located in the file tuenc.def:

\DeclareTextCommand{\textasteriskcentered}\UnicodeEncodingName{%
  \iffontchar\font"2217 \char"2217 \else
    \begingroup
      \fontsize
       {\the\dimexpr1.2\dimexpr\f@size pt\relax}%
       {\f@baselineskip}%
      \selectfont
      \raisebox{-0.6ex}[\dimexpr\height-0.6ex][0pt]{*}%
    \endgroup
  \fi
}

[stone-zeng]

Everything goes OK after loading the xunicode package. I guess that this problem appears because fontspec and ctex all become independent of xunicode recently.

[qinglee]

\textasteriskcentered is exactly the same as * (U+002A) in xunicode:

\DeclareUTFcharacter[\UTFencname]{x002A}{\textasteriskcentered}

[wspr]

Interesting discussion but I agree this isn't a fontspec issue.