public final class ReferenceStage extends Object
REFERENCE (specification Section 14.2) as the reference runner implements it
(conformance/run.py, stage_reference): one reference space for every object that carries a
ref (REF_DUPLICATE), every reference names an object (REF_DANGLING) of an allowed
kind (REF_WRONG_TARGET), and owner and parent chains do not return to themselves
(REF_OWNER_CYCLE).