function f1() {
  typeset -n ref;
  f2;
}

function f2() {
  local var=$0;
  ref=var;
  echo "$0: ref=$ref";
  f3;
  echo "$0: ref=$ref";
}

function f3() {
  echo "$0: ref=$ref";
  local var=$0;
  echo "$0: ref=$ref";
  f4;
  echo "$0: ref=$ref";
}

function f4() {
  echo "$0: ref=$ref";
  local var=$0;
  echo "$0: ref=$ref";
  f5;
  echo "$0: ref=$ref";
}

function f5() {
  echo "$0: ref=$ref";
}

f1;