Hi I was wondering if this is a known issue already or I sho kotlinlang #compiler

Hi, I was wondering if this is a known issue already or I should file one. I expect the program below to not compile because the expression A.B.c can’t be resolved until A is initialised assuming the inner object is path dependent. If the object is not and it’s fully static then

should not have compiled or become accessible.

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dmitriy.novozhilov

10/14/2020, 10:37 AM

Compiler don't (and won't) analyze order of initialization because it's a very complicated (Turing-complete actually) problem, and implementing it may dramatically decrease compiler performance

For such analysis in common case compiler should evaluate whole program to approve that there is no execution ways which may lead to such errors on runtime

You can get NPE in a much simpler case with leaking this during class initialization:

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class A {
    val x: String

    init {
        printX()
        x = ""
    }

    fun printX() {
        println(x.length)
    }
}

fun main() {
    A()
}

And another:

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val x: String = y

val y: String
    get() = x

fun main() {
    println(x.length)
}

kralli

10/14/2020, 1:16 PM

@raulraja I think you were led astray by using the letter

twice in you example.

is referencing the top-level

, not the

in the constructor of

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class A(val s: String) {
    object B {
        val c: String = d
    }
}

val d: String = A.B.c

fun main() {
    println(d) //s is null
}

➕ 2

raulraja

10/14/2020, 1:56 PM

yep, thanks @kralli

and that makes me feel a lot better 😅

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