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