InnerDemo.kt

class Outer {
    val value = 10
    
    class Inner1 {
        fun accessOuter() = println("Outer value = $value") // ❌ Can't access value of Outer class.
    }
    
    inner class Inner2 {
        fun accessOuter() = println("Outer value = $value") // ✅ Can access value of Outer class.
    }
}

fun main() {
    Outer.Inner1().accessOuter()    // #1
    Outer().Inner2().accessOuter()  // #2
}