如果用户试图访问不允许的类型或属性时，会出现警告，但操作可以继续进行。

If the user tries to access types or attributes that are deprecated, a warning is logged, but the operation is allowed to proceed.

youdao

如果客户端代码尝试使用某个约束所不允许的类型来实例化类，则会产生编译时错误。

If client code tries to instantiate your class by using a type that is not allowed by a constraint, the result is a compile-time error.

youdao

它可以很复杂，但是我们决定不允许某些类型的内容在苹果商店中出现……我们将拒绝任何包含越界内容或行为的应用程序。

It can get complicated, but we have decided to not allow certain kinds of content in the App Store... we will reject Apps for any content or behavior that we believe is over the line.

youdao

You can bring any calculator you want, we don't actually have restrictions for calculator types here, but what you can't do, is you can't program any relevant chemical or information about constants in there.

你可以带你想用的任何一种计算器，我们并不限制计算器的类型，但是有一点是不允许的，那就是你不能使用编程的功能来记录,相关的化学常数或其它信息。

麻省理工公开课 - 化学原理课程节选