@NonNull member variable is still null before completion of object construction

class A {
    init {
//         println(str) // compile time error: variable `str` must be initialized
        logContent() // no compile error, but `str` is `null` at this moment
    val str = ""
    private fun logContent() {

fun main() {
    A() // print: null

I know that this is logically wrong.
But, no compile time error, is this a bug of Kotlin ?