[git/perl] unusual syntax?

Hi,

i noticed that this doesn't work for me (Perl 5.10):

sub _close_hash_and_insert_object {
	my ($self) = @_;

	return unless defined($self->{hash_object_pid});

	my @vars = map { 'hash_object_' . $_ } qw(pid in out ctx);

	command_close_bidi_pipe($self->{@vars});
	delete $self->{@vars};
}

$self->{@vars} evaluates to undef. i can't find any mention of using arrays to dereference objects in the manual and elsewhere; is this a mistake?