一般フォーラム

\documentclass[titlepage]{article}
\usepackage[utf8]{inputenc}

\newcommand{\maru}[1]{\ooalign{
\hfil\resizebox{.8\width}{\height}{#1}\hfil
\crcr
\raise.1ex\hbox{\large$\bigcirc$}}}%encircle
\usepackage{fancybox}%about frame
\usepackage{luatexja}%japanese
\usepackage{tikz}
\usetikzlibrary{positioning}
\usetikzlibrary{cd}%tikzcd
\usetikzlibrary{decorations.pathmorphing}
\usepackage{xcolor}
\usepackage{graphics}%reverse
%$\usepackage[margin=15mm]{geometry}%Make margin small
\usepackage{graphicx}%about scalebox
\usepackage{amsmath,amsfonts,amsthm,amssymb,amscd,ascmac}%in order to higher formula and mathfrak and so on.
\usepackage{latexsym, mathtools}%arrow
\usepackage[T1]{fontenc}%※
\usepackage{textcomp}%※
\usepackage{bussproofs}%prooftree
\usepackage{pifont}
\usepackage{subfigure}
\usepackage{lscape}%%revolve
\usepackage{stmaryrd}%bracket
\usepackage{cancel}%diagonal line on a letter
\usepackage{hyperref}%
\usepackage{comment}

\newtheorem*{defi}{Definition}
\newtheorem*{thm}{Theorem}
\newtheorem*{prop}{Proposition}
\newtheorem*{lem}{Lemma}
\newtheorem*{exa}{Example}
\newtheorem*{cla}{Claim}
\newtheorem*{exe}{Exercise}
\newtheorem*{cor}{Corollary}
\newtheorem*{rem}{Remark}

\newcommand{\red}[1]{\textcolor{red}{#1}}

\renewcommand{\baselinestretch}{1.3}%Leave a space between lines

%\usepackage{fancyhdr}

%\pagestyle{fancy}
%\rhead{\thepage}%
%\parindent = 0pt%no indent

\begin{document}

\begin{prooftree}
\AxiomC{$\mathcal{G}_{\neg A}\left(
\parbox{.2\linewidth}{
\begin{prooftree}
\alwaysNoLine
\AxiomC{$\mathcal{D'}$}
\UnaryInfC{$A,\Gamma\Rightarrow$}
\end{prooftree}}\right)$}
\RightLabel{$(An)$}
\UnaryInfC{$\Gamma\Rightarrow\neg A$}
\end{prooftree}

\end{document}

の様に入力したのですが以下のようなエラーが発生し出力されません

main.tex
line 1022
! Proof tree badly specified..
\DisplayProof ...age {Proof tree badly specified.}
\fi \edef \curBox {\thecur...
\end{prooftree}}\right)$}

cloudlatexでやっています。

やりたいことは証明図の一部を括弧で覆いその左横に文字を出力したいです。

よろしければご教授お願いします。