How can I change math font with \setmathfont inside a group?

Question

Consider the following test file and compile it with LuaTeX (TeXLive 2016):

\documentclass{article}
\usepackage[math-style = TeX]{unicode-math}

\setmainfont{texgyretermes}[
  Extension = .otf,
  UprightFont = *-regular,
  BoldFont = *-bold,
  ItalicFont = *-italic,
  BoldItalicFont = *-bolditalic,
  ]

\setsansfont{texgyreadventor}[
  Extension = .otf,
  UprightFont = *-regular,
  BoldFont = *-bold,
  ItalicFont = *-italic,
  BoldItalicFont = *-bolditalic,
  ]

\setmathfont{Latin Modern Math}

\begin{document}

\begin{equation}
  \int_{t = 0}^{x^2} t dt
\end{equation}

\setmathfont[range=up/{greek,Greek,latin,Latin,num}]{texgyreadventor-regular}
\setmathfont[range=it/{greek,Greek,latin,Latin,num}]{texgyreadventor-italic}
\setmathfont[range = {}]{Latin Modern Math}

\begin{equation}
  \int_{t = 0}^{x^2} t dt
\end{equation}

\setmathfont{Latin Modern Math}

\begin{equation}
  \int_{t = 0}^{x^2} t dt
\end{equation}

% {
%   \setmathfont[range=up/{greek,Greek,latin,Latin,num}]{texgyreadventor-regular}
%   \setmathfont[range=it/{greek,Greek,latin,Latin,num}]{texgyreadventor-italic}
%   \setmathfont[range = {}]{Latin Modern Math}

%   \begin{equation}
%     \int_{t = 0}^{x^2} t dt
%   \end{equation}
% }

\end{document}

If I uncomment the last lines, LuaTeX hangs forever. How can I change math font inside a group?

---

EDIT

I'm well aware that I should not use a non math font to do math but, unfortunately, a sans serif math font does not yet exist, AFAIK.

The problem does not appear to be linked with the fact that I use a non math font.

\documentclass{article}
\usepackage[math-style = TeX]{unicode-math}

\setmathfont{Latin Modern Math}

\begin{document}

\begin{equation}
  \int_{t = 0}^{x^2} t dt
\end{equation}

\setmathfont{Asana-Math}

\begin{equation}
  \int_{t = 0}^{x^2} t dt
\end{equation}

\setmathfont{Latin Modern Math}

\begin{equation}
  \int_{t = 0}^{x^2} t dt
\end{equation}


% {
%   \setmathfont{Asana-Math}

%   \begin{equation}
%     \int_{t = 0}^{x^2} t dt
%   \end{equation}
% }


\end{document}

However, as @cfr suggested, I should use \mathversion: the following works.

\documentclass{article}
\usepackage[math-style = TeX]{unicode-math}

\setmathfont[version=lm]{Latin Modern Math}
\setmathfont[version=asana]{Asana-Math}

\mathversion{lm}

\begin{document}

\begin{equation}
  \int_{t = 0}^{x^2} t dt
\end{equation}

\mathversion{asana}

\begin{equation}
  \int_{t = 0}^{x^2} t dt
\end{equation}

\mathversion{lm}

\begin{equation}
  \int_{t = 0}^{x^2} t dt
\end{equation}


{
  \mathversion{asana}

  \begin{equation}
    \int_{t = 0}^{x^2} t dt
  \end{equation}
}

\end{document}

Answer 1

There are really two problems here.

The first is that unicode-math really wants opentype fonts with a proper math table. It only works with fonts lacking this at all, as I understand it, because the configuration falls through to setting the applicable range to up, despite the font lacking anything which usually enables the setting of ranges etc.

The usual way to set an alternative set of maths fonts is to declare an alternative maths version e.g. bold versus normal. unicode-math supports this. This basically works, as your example shows.

However, the second problem is that it seems to be impossible to combine the use of range with version. Setting a range affects all maths versions rather than just the specified one, as I demonstrate in this question.