use strict;
use warnings;
use feature 'say';
no autovivification;
use Data::Dump qw/pp/;
my @ary;
pp exists $::{non};
pp exists $::{other};
pp exists (&non) ;

push @ary,  exists (&non) ;
say scalar(@ary)

##</code><code>##

1     # *non exists after compilation of &non
""       # *other doesn't exist
()       # sub &non doesn't exist but empty list returned
0        # @ary has consequently no elements 

##</code><code>##

 1
""
""
1