This smart casting thing, the more I think about i...

# announcements

[groostav]

This smart casting thing, the more I think about it the more work it becomes:

fun `kotlin is pretty smart`(){
    val nullableSet: Set<Int>? = setOf(1, 2, 3)
    
    when(nullableSet?.size){ 
        null -> {}
        else -> { nullableSet.first() }
    }
}

I would've thought that I'd need a nullableSet!! in the second case.

does that mean the smart-cast system was able to infer that

well the expression nullableSet?.size wasn't null, and size can never be null, so nullableSet must also not be null, so I can smart-cast it to Set<Int>

if so, that kotlinc is one sharp cookie

[Dominaezzz]

I think it inferred it from the assignment actually.

[serebit]

Dominic is incorrect, it did infer it from the null case in the when expression. Kotlinc is very good at smart-casting