boolean retainAll(@Nonnull HashShortSet thisC, @Nonnull Collection<?> c) { if (c instanceof ShortCollection) return retainAll(thisC, (ShortCollection) c); if (thisC == (Object) c) throw new IllegalArgumentException();
boolean retainAll(@Nonnull HashShortSet thisC, @Nonnull Collection<?> c) { if (c instanceof ShortCollection) return retainAll(thisC, (ShortCollection) c); if (thisC == (Object) c) throw new IllegalArgumentException();