public static void assignNativeSlotValue(Proposition prop, Thing self, StorageSlot slot, Stella_Object value) {
    if (Logic.skolemP(value)) {
      return;
    }
    { Stella_Object oldvalue = StandardObject.readSlotValue(self, slot);

      if (Stella_Object.eqlP(oldvalue, value)) {
        return;
      }
      if (oldvalue != null) {
        Proposition.signalUnificationClash(prop, oldvalue, value);
      }
      StandardObject.putSlotValue(self, slot, value);
    }
  }