php foreach行声明变量的作用范围问题

<?php

$arr1 = array(1,3,5,7,9);
$arr2 = array(10,30,50,70,90);

foreach ($arr1 as $k => &$v) {
        # do nothing
}

echo "================\n";
echo "$v\n";

foreach ($arr2 as $k => $v) {
        # do nothing
}

echo "================\n";
echo "$v\n";

echo "================\n";
var_export($arr1);
echo "\n================\n";
var_export($arr2);
echo "\n================\n";

# 最后运行结果如下：
# 说明：foreach行中的变量的作用范围涵盖foreach行外的部分
/*
$ php test_bug.php
================
9
================
90
================
array (
  0 => 1,
  1 => 3,
  2 => 5,
  3 => 7,
  4 => 90,
)
================
array (
  0 => 10,
  1 => 30,
  2 => 50,
  3 => 70,
  4 => 90,
)
================
**/

?>

结论：foreach行中声明的变量的作用范围涵盖foreach行外的部分，只有{}大括号内声明的变量才是语句块变量范围