void addFacts(DfaMemoryState memState, DfaValue value) {
      if (myDfType == DfType.TOP) return;
      DfType newType = memState.getDfTypeIncludingDerived(value);
      myDfType = myDfType.join(newType);
    }
void addFacts(DfaMemoryState memState, DfaValue value)