This starts to tickle one of my sore points with Perl. In DBM::Deep, there is a lot of code that says something like:

my $r = Scalar::Util::reftype( $thing );
my $tied;
if ( $r eq 'ARRAY' ) {
    $tied = tied @$r;
}
elsif ( $r eq 'HASH' ) {
    $tied = tied %$r;
}
else { die "How did we get '$r'??\n"; }
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There's a number of those problems, but arrays and hashes being so different sucks for me. Frankly, I don't care (nor want to care) about how they're implemented. If I want to ask, I'll ask and each should be able to answer is_hash() and is_array(). But, I shouldn't be forced to deference like that. It sucks.