13.1: Note that references may occur to other enclosing classes

For JEP 181 (JDK-8177019), it was proposed to expand the 13.1 rule about references to enclosing classes, from:

"Every nested class and nested interface must have a symbolic reference to its immediately enclosing class (§8.1.3)."

to:

"Every nested class and nested interface must have symbolic references to all of its enclosing classes (§8.1.3)."

The argument for including a reference to every enclosing class, not just the immediately enclosing class, centered on the InnerClasses attribute. Namely, if a nested class's class file contained a reference to the immediately enclosing class, then the InnerClasses attribute required a reference to the enclosing class of that class, and so on. However, this argument fails to acknowledge that local and anonymous classes have an outer_class_info_index of 0; this breaks the chain, and no further enclosing classes are referenced.

Still, it may be useful to add a non-normative observation about classes that may be referenced:

"A nested class or nested interface may also include symbolic references to other enclosing classes."