#!/usr/bin/perl 
use strict;
use warnings;  

sub mysub (\@) {

    my $arg = $_;
    print ref $arg."\n";

}

my (@array, %hash, $scalar);

mysub (\@array);
mysub (\%hash);
mysub (\$scalar);

mysub (@array);    # This is the only one which compiles
mysub (%hash);
mysub ($scalar);

mysub (qw(This is a list));

##</code><code>##

Type of arg 1 to main::mysub must be array (not reference constructor) at C:\gash.pl line 15, near "@array)"
Type of arg 1 to main::mysub must be array (not reference constructor) at C:\gash.pl line 16, near "%hash)"
Type of arg 1 to main::mysub must be array (not single ref constructor) at C:\gash.pl line 17, near "$scalar)"
Type of arg 1 to main::mysub must be array (not private hash) at C:\gash.pl line 20, near "%hash)"
Type of arg 1 to main::mysub must be array (not private variable) at C:\gash.pl line 21, near "$scalar)"
Type of arg 1 to main::mysub must be array (not list) at C:\gash.pl line 23, near "qw(This is a list))"
Execution of C:\gash.pl aborted due to compilation errors.