Is there a fundamental difference between `IntArra...

# announcements

[bdawg.io]

Is there a fundamental difference between IntArray and Array<Int>? If so, is there a reason why the compiler doesn’t treat them as type aliases?

[diesieben07]

Yes, there is. Array<Int> is an array of boxed values (like java.lang.Integer). IntArray is an optimized array of primitive values.

[rook]

Perhaps more precisely IntArray is int[] whereas Array<Int> is Integer[].

[diesieben07]

Yes, I was trying to explain it without being specific to Java.

[diesieben07]

On JS IntArray is using typed arrays, Array<Int> is just a normal javascript array, as far as I know.

[rook]

Good point, I often overlook the JS and native applications of Kotlin.

[bdawg.io]

JS has actual typed arrays? huh

[bdawg.io]

Doesn’t the compiler change Int to int and Int? to Integer when the type is alone? So it seems odd to me that Array<Int> isn’t converted to int[] but still have Array<Int?> go to Integer[]

[diesieben07]

The problem is that Array<Int> needs to be assignable to things like Array<out Any>.

[diesieben07]

If Array<Int> compiled to int[], every array would have to be represented as Object on the JVM and you would have to use java.reflect.Array for all accesses.

[bdawg.io]

Ahh, variance is a good reason — it’s different having to consider that primitives are more relevant in Java than they are in Kotlin