[Tex/LaTex] pdfTeX warning (ext4): destination with the same identifier (name{choice.1}) has been already used, duplicate ignored

examhyperrefpdftexwarnings

when compiling the following document:

\documentclass[11pt]{exam}

\usepackage{amsmath,amsbsy,amssymb,amsthm,cases,blkarray,mathrsfs,amsrefs,amsfonts,latexsym}
\usepackage{enumerate,enumitem,textcomp,stackengine,bbm}
\usepackage{setspace,xifthen,fullpage,ragged2e,multicol,multirow,makecell}
\usepackage[english]{babel}
\usepackage[usenames,dvipsnames,svgnames,table]{xcolor}% see http://ctan.org/pkg/xcolor
\definecolor{OliveGreen}{cmyk}{0.64,0,0.95,0.40}
\definecolor{CadetBlue}{cmyk}{0.62,0.57,0.23,0}
\definecolor{lightlightgray}{gray}{0.93}
\definecolor{darkblue}{rgb}{0,0,.6}
\definecolor{darkred}{rgb}{.7,0,0}
\definecolor{darkgreen}{rgb}{0,.6,0}
\definecolor{red}{rgb}{.98,0,0}
\usepackage{listings,acronym,bbding, pmboxdraw}
\usepackage{pgfplots,graphics,graphicx,longtable,sectsty}
\usepackage[colorlinks,pdfusetitle,urlcolor=darkblue,citecolor=darkblue,linkcolor=darkred,bookmarksnumbered,plainpages=false,pageanchor]{hyperref}
\usepackage{datetime}
\usepackage[font=small,skip=0pt]{caption}
\usepackage[T1]{fontenc}
\usepackage[english]{babel}
\usepackage{pstricks,pst-node,pst-tree,titlesec,extramarks,totcount}
\usepackage{pdfpages,bbding,grffile}
\usepackage{xspace,verbatim} % used to display code


\usepackage[inner=1.5cm,outer=1.5cm,top=2.5cm,bottom=2.5cm]{geometry} 
\usepackage{silence}
\usepackage{cleveref}

\printanswers    
\addpoints 



% For the exam package
\newcommand{\qs}{\question[1\half]}
\newcommand{\ch}{\choice}
\newcommand{\cc}{\CorrectChoice}
\CorrectChoiceEmphasis{\slshape\color{OliveGreen}} 
\renewcommand{\thechoice}{\alph{choice}}
\renewcommand{\choicelabel}{(\thechoice{})}

\pointpoints{mark}{marks} 
\pointpoints{}{} 
\hpword{Marks} 



\newcommand{\al}{\alpha}
\newcommand{\si}{\sigma}
\newcommand{\ybar}{\bar{y}} 
\newcommand{\xbar}{\bar{x}} 


\begin{document}

\begin{questions}


\qs Which one
\vskip0.02in
\begin{choices}
\cc According 
\ch For 
\ch IF 
\ch All 
\end{choices}


\qs Based on 
\vskip0.02in
\begin{choices}
\ch mou
\cc ske
\ch s
\ch un
\end{choices}

\qs Suppos
\vskip0.02in
\begin{oneparchoices}
\ch $0.67$
\cc $0.56$
\ch $0.48$
\ch $0.64$
\end{oneparchoices}

\qs You a
\vskip0.02in
\begin{oneparchoices}
\ch $-1/16$
\cc $-1/8$
\ch $-3/16$
\ch $-1/2$
\end{oneparchoices}
\end{questions}

\end{document}

I have tried find ways to get rid of this warning by searching in other places and I have read PDFTeX destination … ignored and the other question in this place pdfTeX warning: destination with same identifier has been already used, duplicate ignored (weird behaviour). What I get is this warning "pdftex warning (ext4): destination with the same identifier (name{choice.1}) has been already used, duplicate ignored" which occurs more than 48 times and different from the one already posted. All what I found has name{page.1} or name{theorem.1}

MWE (added by cfr based on Werner's example)

\documentclass{exam}
\usepackage{hyperref}
\printanswers
\addpoints
\begin{document}
\gradetable
\begin{questions}
  \question[1\half]
    Suppose
  \begin{oneparchoices}
    \choice $0.67$
    \CorrectChoice $0.56$
    \choice $0.48$
    \choice $0.64$
  \end{oneparchoices}
  \question[1\half]
    You a
  \begin{oneparchoices}
    \choice $-1/16$
    \choice $-3/16$
    \CorrectChoice $-1/8$
    \choice $-1/2$
  \end{oneparchoices}
\end{questions}

Best Answer

It seems that exam has poor compatibility with hyperref.

You just need to add a definition for \theHchoice, so hyperref will pick up this instead of \thechoice. Using \arabic{question}.\arabic{choice} will ensure a unique tag.

\documentclass{exam}
\usepackage{hyperref}

%% keep hyperref happy    
\newcommand{\theHchoice}{\arabic{question}.\arabic{choice}}

\printanswers
\addpoints
\begin{document}

\gradetable
\begin{questions}
  \question[1\half]
    Suppose
  \begin{oneparchoices}
    \choice $0.67$
    \CorrectChoice $0.56$
    \choice $0.48$
    \choice $0.64$
  \end{oneparchoices}
  \question[1\half]
    You a
  \begin{oneparchoices}
    \choice $-1/16$
    \choice $-3/16$
    \CorrectChoice $-1/8$
    \choice $-1/2$
  \end{oneparchoices}
\end{questions}

\end{document}
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