Hi, This crash is reported with a user in 0.95
https://tex.stackexchange.com/questions/343599/how-do-i-resolve-the-assertion-failed-popups But I see a failure with a cygwin texlive build of 1.01 This is LuaTeX, Version 1.0.1 (TeX Live 2017/dev) restricted system commands enabled. (./ww114.texassertion "varmem[(p)].hh.v.RH!=null" failed: file "../../../source/texk/web2c/luatexdir/tex/mlist.w", line 4050, function: mlist_to_hlist Aborted (core dumped) The test file as plain tex \def\isomorphism{% \mathrel{% \mathpalette\xisomorphism{}% }% } \def\xisomorphism#1#2{% % Calculate the amount of moving \sim up as in \simeq \setbox0\hbox{$#1\simeq$}% \setbox2\hbox{$#1\sim$}% \dimen0=\ht0 % \advance\dimen0 by -\ht2 % %---------------------------- % Compose the two symbols %---------------------------- \setbox0\hbox{% \lower1.9\dimen0\hbox{% $#1\relbar\isomorphismxjoinrel\relbar$% }% }% \rlap{% \hbox to \wd0{% \hfill\raise\dimen0\hbox{$#1\sim$}\hfill }% }% \copy0 % } \def\isomorphismxjoinrel{% \mathrel{% \mkern-3.4mu % \mkern-1mu % \nonscript\mkern1mu % }% } $$ A \isomorphism B^{C \isomorphism D^{E \isomorphism F}} $$ \bye
