This program fails to compile:

class Outer {
    interface A { }
    interface B { }
    
    
    class Inner1 {
        Inner1() {
            this(new A() {
                class Inner2 {
                    Inner2() {
                        this(new B() { { m(); g(); } });
                    }

                    Inner2(Object o) { }
                }

                void m() { }
            });
        }

        Inner1(Object o) { }
    }
    void g() { }
}

Error is:

error: no enclosing instance of type Outer is in scope
                        this(new B() { { m(); g(); } });
                                              ^
1 error