这通常不是行为人希望返回时的值。
This is generally not a behavior one wants when returning by value.
如果返回值不是由调用者使用的行为是不是不确定。
The behaviour is not undefined if the return value is not used by the caller.
如果未返回深层克隆，则运行时行为将不可确定。
If a deep clone is not returned, the run-time behavior is undefined.
如果未返回深层克隆，则运行时行为将不可确定。
If a deep clone is not returned, the run-time behavior is undefined.
应用推荐