Is this behaviour documented anywhere? Why does re...

# announcements

[Joris PZ]

Is this behaviour documented anywhere? Why does reallyReallyReallyLong become zero? Does the result after multiplication simply get truncated to 64 bits?

[Dmitry Kandalov]

If the result is greater than Long.MAX_VALUE, it will silently overflow just like long in java. Documented Somewhat documented here https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html for JVM and I assume it works in a similar way on other platforms. It might be a good idea to have more documentation to make adoption by non-java programmers easier.

[Joris PZ]

I have been programming Java for 15 years, have seen integer and long multiplication roll over into the negatives all the time, and yet somehow when I ran into the case above I immediately forgot all that and wondered why it didn't throw an exception... Thanks @Dmitry Kandalov and @karelpeeters

[elizarov]

It actually gives you a warning in IDEA.

[Joris PZ]

Oh that's neat! I tested this on play.kotlinlang.org and I don't recall seeing such a warning there

[elizarov]

Generally, programming in IDEA is way better that in any online editor or other kind of editor. You get much more insight into your code.