Why is my nested class not accessible? (Kotlin)

I was trying to follow an example from the nested classes documentation: Kotlin docs – Nested and inner classes

So I tried:

fun main(){
    var tester = Test()
    println(tester.x) // 42
    tester.Foo().bar() // compiler error - unresolved reference: Foo!!!
}

class Test {
    var x:Int = 42
    class Foo {
        fun bar() = println("foobar!")
    }
}

However, the nested class was not accessible.
I’m obviously missing something really obvious.

>Solution :

If you’re not trying to create an inner class, then a nested class should be referenced like so:

fun main() {
    var tester = Test()
    println(tester.x)  // 42

    // Static reference 
    Test.Foo().bar() // foobar!
}

class Test {
    var x:Int = 42
    inner class Foo {
        fun bar() = println("foobar!")
    }
}

As @broot said in his comment:

Nested classes are static, so you don’t create them from instances