a declaring

I'm not sure, but why this can work?

use strict;
use warnings;
use Data::Dumper;

my $y=0;
my @[EMAIL PROTECTED]
 =(1,2,3) if $y;
print Dumper \@[EMAIL PROTECTED]
 $y is false, it seems @[EMAIL PROTECTED]
 shouldn't be declared.
But why the last print can work?

-- 
J. Peng - QQMail Operation Team
eMail: peng.kyo@[EMAIL PROTECTED]
  AIM: JeffHua