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kotlinlang

Hello. Is there a way (contracts?), or will there ever be a way to do the following?
- mark a function as side-effect-free, so that the compiler can warn if we call the function and do nothing with what it returns?
- mark a class (I’m thinking of a JPA entity here) as only usable in a single thread, so that instance variables which have been checked as not null do not need to be used with `?.` or `!!`
Sorry if that has been asked before. It’s been a long time I haven’t been here :slightly_smiling_face:

<https://youtrack.jetbrains.net/issue/KT-18024>

And the second one: it's not even about threads, what if you call a function that happens to be able to access the instance and it sets a field to `null`?

Thanks. Upvoted! You’re right about the second case of course. I guess the compiler  could be able to check that, too, but I agree it’s probably not a good idea, since the code would break as soon as the object is used between the null check and the usage of the variable. Thanks again <@U5UU34LPK>