I use \setmainfont{CMU Serif} to change the font. But CMU Serif doesn’t support small caps emphasis font as you can see with the following MWE:
\documentclass[a5paper,10pt,twoside,french]{book}
\usepackage{fontenc}
\usepackage{fontspec}
\setmainfont{CMU Serif}
\begin{document}
\textsl{\textsc{gnu}'s not Unix} (\verb|\textsl{}|) \par
\textit{\textsc{gnu}'s not Unix} (\verb|\textit{}|) \par
\emph{GNU: \textsc{gnu}'s not Unix} (\verb|\emph{}|)
\end{document}
Witch produce the following rendering:
But the default font (witch seems to be European Computer Modern) produce a well render according to this tread.
So is theire a way to set European Computer Modern just for small caps inside emphasis context (or reverse)?




