use vars '$i';
$i = 123;

sub foo {
  my $arg = shift;
  print "$arg, $i\n";
}

foreach $i (0..2) {
  foo($i);
}
foo('x'); # obviously alias works only within the loop

# Prints,
# 0,0
# 1,1
# 2,2
# x,123

##</code><code>##

my $i;
$i = 123;

sub foo {
  my $arg = shift;
  print "$arg, $i\n";
}

foreach $i (0..2) {
  foo($i);
}
foo('x');

# Prints,
# 0,123
# 1,123
# 2,123
# x,123