a[0]='/'
set -- /

# these should all result in the empty (null) string

recho "${a[0]%?}"
recho "${a[*]%?}"
recho "${a[@]%?}"

recho "${*%?}"
recho "${@%?}"

recho "${a[0]#?}"
recho "${a[*]#?}"
recho "${a[@]#?}"

recho "${*#?}"
recho "${@#?}"

recho "${a[0]/\//}"
recho "${a[*]/\//}"
recho "${a[@]/\//}"

recho "${*/\//}"
recho "${@/\//}"

recho "${a[0]:1:1}"
# these next four will all echo /

# arrays are zero-based
recho "${a[*]:0:1}"
recho "${a[@]:0:1}"
# but the positional parameters start at 1
recho "${*:1:1}"
recho "${@:1:1}"

a[0]=''
set -- ''

# arrays are zero-based
recho "${a[*]:0:1}"
recho "${a[@]:0:1}"

recho "${*:1:1}"
recho "${@:1:1}"

# these should all result in the empty (null) string, or quoted as such

recho "${a[0]@Q}"
recho "${a[*]@Q}"
recho "${a[@]@Q}"

recho "${*@Q}"
recho "${@@Q}"

recho "${a[0]@L}"
recho "${a[*]@L}"
recho "${a[@]@L}"

recho "${*@L}"
recho "${@@L}"

# examples from the bug report
unset -v a

a[0]='/'
for i in "${a[@]%/}"; do recho "$i"; done

a[0]=''
for i in "${a[@]}"; do recho "$i"; done

a[0]='/'
a[1]="//"
for i in "${a[@]%/}"; do recho "$i"; done

unset -v x y
x=('/')
y=("${x[@]%/}")

echo "${#x[@]}:${#y[@]}"