bug in 4.4?

[L A Walsh]

If I set bash to complain about uninitialized variables
w/-u, I get inconsistent, and seemingly incorrect behavior:

>  echo $BASH_VERSION
4.4.5(1)-release
>  set -u
>  echo ${undefvar}
bash: undefvar: unbound variable
>  echo ${undefvar[@]}
                                    # no message about unbound var
>  echo ${undefvar}    
bash: undefvar: unbound variable     # -u is still in effect