use strict;
use warnings;

my %hash=(a=>1,b=>2,c=>4,d=>8);
local $,="\t";
local $\="\n";

print @hash{qw'a b c d'}; # This throws a warning!
print @hash{qw(a b c d)}; # This doesnt!

__END__
Scalar value @hash{qw'a b c d'} better written 
  as $hash{qw'a b c d'} at D:\temp\hashbug.pl line 8.
1	2	4	8
1	2	4	8


##</code><code>##

$ref=\%hash; 
print @{$ref}{qw'a b c'};