why the nested class will call the method of out class when the method not exist in nested class

class Outer {
    static void out() {
        System.out.println("hello world");
    }
    static class Inner {
    }

    static void main(String[] args) {
        //Intellij Note: No candidates found for method call
        Outer.Inner.out();
    }
}

After running this script, the Outer.out will be executed successuful. Why? I get this info from the official doc:

The implementation of anonymous inner classes and nested classes follow Java closely, but there are some differences, e.g. local variables accessed from within such classes don’t have to be final. We piggyback on some implementation details we use for groovy.lang.Closure when generating inner class bytecode.

Anybody can explain why this script can be executed successful?