f() { declare -p ${!var*} | grep ^var; declare -p var ; }

var[0]=X var[@]=Y f

unset -f f
unset -v var

typeset -A var

f() { declare -p ${!var*}; }

var[0]=X var[@]=Y
f

: ${THIS_SH:=./bash}
env 'v[0]=help' ${THIS_SH} -c 'printenv "v[0]"'

unset -v var

f() { test -v 'var[0]'; echo $?; }
var[0]=X f

unset -v var