【请教】在函数里面定义函数后，调用，为什么会报错？
<?php
function test5(){
function test6(){
echo 'this is test6';
return 888;
}
echo 123;
return test6();
}
test5();
echo '<hr />';
var_dump(test5());上面这段代码报错：
Fatal error: Cannot redeclare test6() (previously declared in E:\xampp\htdocs\test\testecho.php:4) in E:\xampp\htdocs\test\testecho.php on line 4
