#!/usr/bin/perl -w
use strict;

sub ten { 10 }

print "9 .. 10 - 1 with constant\n";
for my $i (9 .. ten - 1) {
  print $i, "\n";
}
print "-> unexpected\n\n";

##</code><code>##

corion@outerlimits:~/Projekte$ perl -MO=Deparse tmp.pl 
BEGIN { $^W = 1; }
use strict;
sub ten {
    10;
}
print "9 .. 10 - 1 with constant\n";
foreach my $i (9 .. ten(-1)) {
    print $i, "\n";
}
print "-> unexpected\n\n";
tmp.pl syntax OK

##</code><code>##

sub ten() { 10 };

##</code><code>##

use constant ten => 10;