\documentclass[12pt]{report}
\usepackage[]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{fullpage}
\usepackage{coqdoc}
\usepackage{amsmath,amssymb}
\usepackage{url}
\begin{document}
\coqlibrary{Coqdoc.bug5648}{Library }{Coqdoc.bug5648}

\begin{coqdoccode}
\coqdocnoindent
\coqdockw{Lemma} \coqdef{Coqdoc.bug5648.a}{a}{\coqdoclemma{a}} : \coqexternalref{True}{http://coq.inria.fr/stdlib/Coq.Init.Logic}{\coqdocinductive{True}}.\coqdoceol
\coqdocnoindent
\coqdockw{Proof}.\coqdoceol
\coqdocnoindent
\coqdoctac{auto}.\coqdoceol
\coqdocnoindent
\coqdockw{Qed}.\coqdoceol
\coqdocemptyline
\coqdocnoindent
\coqdockw{Variant} \coqdef{Coqdoc.bug5648.t}{t}{\coqdocinductive{t}} :=\coqdoceol
\coqdocnoindent
\ensuremath{|} \coqdef{Coqdoc.bug5648.A}{A}{\coqdocconstructor{A}} \ensuremath{|} \coqdef{Coqdoc.bug5648.Add}{Add}{\coqdocconstructor{Add}} \ensuremath{|} \coqdef{Coqdoc.bug5648.G}{G}{\coqdocconstructor{G}} \ensuremath{|} \coqdef{Coqdoc.bug5648.Goal}{Goal}{\coqdocconstructor{Goal}} \ensuremath{|} \coqdef{Coqdoc.bug5648.L}{L}{\coqdocconstructor{L}} \ensuremath{|} \coqdef{Coqdoc.bug5648.Lemma}{Lemma}{\coqdocconstructor{Lemma}} \ensuremath{|} \coqdef{Coqdoc.bug5648.P}{P}{\coqdocconstructor{P}} \ensuremath{|} \coqdef{Coqdoc.bug5648.Proof}{Proof}{\coqdocconstructor{Proof}} .\coqdoceol
\coqdocemptyline
\coqdocnoindent
\coqdockw{Definition} \coqdef{Coqdoc.bug5648.d}{d}{\coqdocdefinition{d}} \coqdocvar{x} :=\coqdoceol
\coqdocindent{1.00em}
\coqdockw{match} \coqdocvariable{x} \coqdockw{with}\coqdoceol
\coqdocindent{1.00em}
\ensuremath{|} \coqref{Coqdoc.bug5648.A}{\coqdocconstructor{A}} \ensuremath{\Rightarrow} 0\coqdoceol
\coqdocindent{1.00em}
\ensuremath{|} \coqref{Coqdoc.bug5648.Add}{\coqdocconstructor{Add}} \ensuremath{\Rightarrow} 1\coqdoceol
\coqdocindent{1.00em}
\ensuremath{|} \coqref{Coqdoc.bug5648.G}{\coqdocconstructor{G}} \ensuremath{\Rightarrow} 2\coqdoceol
\coqdocindent{1.00em}
\ensuremath{|} \coqref{Coqdoc.bug5648.Goal}{\coqdocconstructor{Goal}} \ensuremath{\Rightarrow} 3\coqdoceol
\coqdocindent{1.00em}
\ensuremath{|} \coqref{Coqdoc.bug5648.L}{\coqdocconstructor{L}} \ensuremath{\Rightarrow} 4\coqdoceol
\coqdocindent{1.00em}
\ensuremath{|} \coqref{Coqdoc.bug5648.Lemma}{\coqdocconstructor{Lemma}} \ensuremath{\Rightarrow} 5\coqdoceol
\coqdocindent{1.00em}
\ensuremath{|} \coqref{Coqdoc.bug5648.P}{\coqdocconstructor{P}} \ensuremath{\Rightarrow} 6\coqdoceol
\coqdocindent{1.00em}
\ensuremath{|} \coqref{Coqdoc.bug5648.Proof}{\coqdocconstructor{Proof}} \ensuremath{\Rightarrow} 7\coqdoceol
\coqdocindent{1.00em}
\coqdockw{end}.\coqdoceol
\end{coqdoccode}
\end{document}