$ perl -le '@x = qw(1 2 3); $x = 1; *y = *x; undef @x; print "$y [@y]"'
1 []

##</code><code>##

$ perl -le '@x = qw(1 2 3); $x = 1; *y = *x; undef *x; print "$y [@y]"'
1 [1 2 3]