D:\>perl -MData::Dumper -e "sub x{1 for 1..5};@y=x();print 'ha' if defined @y"
ha

##</code><code>##

$ perl -MData::Dumper -e 'sub x{1 for 1..5};@y=x();print Dumper(\@y)'
$VAR1 = [
          ''
        ];

##</code><code>##

$ perl -wle 'sub x{};@y=x(); print "array" if @y'
(nothing)
$ perl -wle 'sub x{};%y=x();print "hash" if %y'
(nothing)
$ perl -wle 'sub x{1..3};@y=x(); print "array" if @y'
array
$ perl -wle 'sub x{a => 1};%y=x();print "hash" if %y'
hash