LaTeX reader: handle `##` macro arguments properly.

These turn into regular `#` arguments when expanded.

Closes #8243.

1 files changed, 23 insertions, 0 deletions

diff --git a/test/command/8243.md b/test/command/8243.md
new file mode 100644
index 000000000..87c800973
--- /dev/null
+++ b/test/command/8243.md
@@ -0,0 +1,23 @@
+```
+% pandoc -f latex
+\newenvironment{topics}{
+\newcommand{\topic}[2]{ \item{##1 / ##2} }
+Topics:
+\begin{itemize}
+}
+{
+\end{itemize}
+}
+
+\begin{topics}
+\topic{Foo}{Bar}
+\topic{Baz}{Bim}
+\end{topics}
+^D
+<p>Topics:</p>
+<ul>
+<li><p><span>Foo / Bar</span></p></li>
+<li><p><span>Baz / Bim</span></p></li>
+</ul>
+```
+