We recently disovered (4909550) that the InnerClass attribute is a necessary
piece of information in order for a compiler to typecheck against class
files in which the inner class is used only in a signature but not in the
constant pool. The VM spec does not require an InnerClass attribute in this
case, but for interoperability it must.

Please update the VM spec to require an InnerClass attribute for any inner
class that is used in a signature. This include member signatures, signature
attributes, and the generic local variable table.