use Types::Standard qw( ArrayRef HashRef ScalarRef );

my ( @thing1, %thing2, $thing3 );

my $union = ArrayRef | HashRef;

$union->check( \@thing1 );   # true
$union->check( \%thing1 );   # true
$union->check( \$thing1 );   # false

( ArrayRef | HashRef | ScalarRef )->check( \$thing1 );   # true