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kotlinlang

The root cause is that `in` resolves to different `contains` with smart cast and without

The weird thing about this example here is that with two different call's to `thing` you are getting two different values.
```
    if (thing != null // This could evaluate to `true`
        &amp;&amp; 
        thing in list // `thing` can be null here.
        ) { // fails
        
    }
```
<@U092308M7>

yes, exactly, that’s why smart-cast doesn’t work

It's a convoluted use case and probably not what the developer means, but it should compile regardless.

It will be the same with a simple `var`, because it can be modified on a different thread

Yes, I don't know why I put that random thing there.

<https://youtrack.jetbrains.com/issue/KT-24621>