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kotlinlang

Just ran across this, which throws an `UnsupportedOperationException`:
```val list = listOf(1, 2)
if (list is MutableList) list.add(3)```
<https://pl.kotl.in/_jfhJy6is>

Why is that? I mean, I get that the list is immutable, but why then can it be cast to MutableList?

<https://stackoverflow.com/questions/52580173/listof-returns-mutablelist>

I see, thanks! So the terrible blunders of the old Java world live on in Kotlin (JVM) :slightly_smiling_face: