好好的点击其他页面，有时候就报这个，一天有个四五次了：

刷新下就又好了

Notice: Constant IN_DISCUZ already defined in /www/wwwroot/xxx/source/class/class_core.php on line 12

Notice: Constant DISCUZ_ROOT already defined in /www/wwwroot/xxx/source/class/class_core.php on line 13

Notice: Constant DISCUZ_CORE_DEBUG already defined in /www/wwwroot/xxx/source/class/class_core.php on line 14

Notice: Constant DISCUZ_TABLE_EXTENDABLE already defined in /www/wwwroot/xxx/source/class/class_core.php on line 15

Fatal error: Cannot declare class core, because the name is already in use in /www/wwwroot/xxx/source/class/class_core.php on line 28