我刚刚通过 synaptic 包管理器（Ubuntu）安装了 texlive-full 包，但我似乎遇到了 expl3 的一些问题。
编译以下文档将返回“缺少 \begin{document}”错误：
\documentclass{article}
\usepackage{nomencl}
\begin{document}
test
\end{document}
记录如下。
This is pdfTeX, Version 3.14159265-2.6-1.40.21 (TeX Live 2020/Debian) (preloaded format=pdflatex 2021.1.19) 19 JAN 2021 12:50
entering extended mode
restricted \write18 enabled.
%&-line parsing enabled.
**test
(./test
LaTeX2e <2020-02-02> patch level 5
L3 programming layer <2020-07-17> (/home/fede/texmf/tex/latex/base/article.cls
Document Class: article 2020/04/10 v1.4m Standard LaTeX document class
(/home/fede/texmf/tex/latex/base/size10.clo
File: size10.clo 2020/04/10 v1.4m Standard LaTeX file (size option)
)
\c@part=\count168
\c@section=\count169
\c@subsection=\count170
\c@subsubsection=\count171
\c@paragraph=\count172
\c@subparagraph=\count173
\c@figure=\count174
\c@table=\count175
\abovecaptionskip=\skip47
\belowcaptionskip=\skip48
\bibindent=\dimen134
)
(/home/fede/texmf/tex/latex/nomencl/nomencl.sty
Package: nomencl 2020/12/29 v5.5 Nomenclature package
(/home/fede/texmf/tex/latex/xkeyval/xkeyval.sty
Package: xkeyval 2020/11/20 v2.8 package option processing (HA)
(/home/fede/texmf/tex/generic/xkeyval/xkeyval.tex
(/home/fede/texmf/tex/generic/xkeyval/xkvutils.tex
\XKV@toks=\toks15
\XKV@tempa@toks=\toks16
(/home/fede/texmf/tex/generic/xkeyval/keyval.tex))
\XKV@depth=\count176
File: xkeyval.tex 2014/12/03 v2.7a key=value parser (HA)
))
(/home/fede/texmf/tex/latex/base/ifthen.sty
Package: ifthen 2014/09/29 v1.1c Standard LaTeX ifthen package (DPC)
)
(/home/fede/texmf/tex/latex/koma-script/tocbasic.sty
Package: tocbasic 2020/09/21 v3.32 KOMA-Script package (handling toc-files)
(/home/fede/texmf/tex/latex/koma-script/scrbase.sty
Package: scrbase 2020/09/21 v3.32 KOMA-Script package (KOMA-Script-independent
basics and keyval usage)
(/home/fede/texmf/tex/latex/koma-script/scrlfile.sty
Package: scrlfile 2020/09/21 v3.32 KOMA-Script package (file load hooks)
(/home/fede/texmf/tex/latex/koma-script/scrlfile-patcholdlatex.sty
Package: scrlfile-patcholdlatex 2020/09/21 v3.32 KOMA-Script package (patching
old LaTeX kernels)
(/home/fede/texmf/tex/latex/koma-script/scrlogo.sty
Package: scrlogo 2020/09/21 v3.32 KOMA-Script package (logo)
))
(/home/fede/texmf/tex/latex/l3packages/xparse/xparse.sty
(/home/fede/texmf/tex/latex/l3kernel/expl3.sty
Package: expl3 2021-01-09 L3 programming layer (loader)
! LaTeX Error: Missing \begin{document}.
See the LaTeX manual or LaTeX Companion for explanation.
Type H <return> for immediate help.
...
l.77 \ExplLoaderFileDate{expl3.sty}}
%
?
! Emergency stop.
...
l.77 \ExplLoaderFileDate{expl3.sty}}
%
You're in trouble here. Try typing <return> to proceed.
If that doesn't work, type X <return> to quit.
Here is how much of TeX's memory you used:
758 strings out of 480906
11450 string characters out of 5910772
253744 words of memory out of 5000000
16402 multiletter control sequences out of 15000+600000
535088 words of font info for 29 fonts, out of 8000000 for 9000
1141 hyphenation exceptions out of 8191
63i,0n,54p,234b,36s stack positions out of 5000i,500n,10000p,200000b,80000s
! ==> Fatal error occurred, no output PDF file produced!
在上面的例子中，我使用了包命名法，但在我看来问题应该出在其他地方：如果我尝试使用 \NewDocumentCommand 或加载包 xparser，我会收到一堆错误。
这似乎与其他问题，但该解决方案（在评论中）对我来说似乎不起作用。
知道发生什么事了吗？