docs: public void makeSameAs(UnconditionalValueDerefSet source) {
          // Copy value numbers
          valueNumbersUnconditionallyDereferenced.clear();
          valueNumbersUnconditionallyDereferenced.or(source.valueNumbersUnconditionallyDereferenced);
          lastUpdateTimestamp = source.lastUpdateTimestamp;
          // Copy dereference locations for each value number
          derefLocationSetMap.clear();
          if (source.derefLocationSetMap.size() > 0) {
              for (Map.Entry<ValueNumber, Set<Location>> sourceEntry : source.derefLocationSetMap.entrySet()) {
                  Set<Location> derefLocationSet = Util.makeSmallHashSet(sourceEntry.getValue());
                  derefLocationSetMap.put(sourceEntry.getKey(), derefLocationSet);
              }
          }
      }