Iterable<LookupElement> (@NotNull Iterable<? extends LookupElement> source, @Nullable Set<? super LookupElement> lifted, @NotNull ProcessingContext context) { Set<LookupElement> srcSet = new ReferenceOpenHashSet<>(source instanceof Collection ? ((Collection<?>)source).size() : myCount); ContainerUtil.addAll(srcSet, source); if (srcSet.size() < 2) { return myNext.classify(source, context); } return new LiftingIterable(srcSet, context, source, lifted); }