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kotlinlang

Can someone explain to me, why <https://kotlinlang.slack.com/archives/C87V9MQFK/p1765112017893829?thread_ts=1765083605.966399&amp;cid=C87V9MQFK|this> behaves as it behaves?

`+2` is valid Kotlin code.
The code produces a warning btw, which is good. It should be even better with the return value checker, since this whole class of "bugs" gets completely elminated

I am not at pc right now, but I don't remember having warning in IDE.

I see warning in playground, but maybe it doesn't show in IDE. It'd definitely show up using the return value checker though
It's valid because unary plus is valid. It has some use cases with DSLs and such. It's just like `-2`, which is not a constant, but the unary minus operator applied to `2`

hm, I see. again I am not sure I remember correctly, but I think when I went to definition via ctrl + click on plus, I didn't end up on unaryPlus

&gt; It's just like `-2`, which is not a constant, but the unary minus operator applied to `2`
This bring some interesting behaviour. For example, the literal `-2147483648` is of type `Int`, even though `2147483648` doesn't fit in an `Int` and is therefore of type `Long`. In fact, even `-(<tel:2147483648|2147483648>)` is of type `Int`. And the value `Long.MIN_VALUE` is `-9223372036854775808` but if you try to use that as a literal you'll get a compiler error because the literal without the sign overflows `Long.MAX_VALUE`. In some other languages, the unary minus is taken as part of the literal itself, so this kind of behaviour doesn't arise.