@Nullable
  private DfaInstructionState[] handleRelationBinop(
      BinopInstruction instruction,
      DataFlowRunner runner,
      DfaMemoryState memState,
      DfaValue dfaRight,
      DfaValue dfaLeft) {
    DfaValueFactory factory = runner.getFactory();
    final Instruction next = runner.getInstruction(instruction.getIndex() + 1);
    DfaRelationValue dfaRelation =
        factory
            .getRelationFactory()
            .createRelation(dfaLeft, dfaRight, instruction.getOperationSign(), false);
    if (dfaRelation == null) {
      return null;
    }

    myCanBeNullInInstanceof.add(instruction);

    ArrayList<DfaInstructionState> states = new ArrayList<DfaInstructionState>();

    final DfaMemoryState trueCopy = memState.createCopy();
    if (trueCopy.applyCondition(dfaRelation)) {
      trueCopy.push(factory.getConstFactory().getTrue());
      instruction.setTrueReachable();
      states.add(new DfaInstructionState(next, trueCopy));
    }

    //noinspection UnnecessaryLocalVariable
    DfaMemoryState falseCopy = memState;
    if (falseCopy.applyCondition(dfaRelation.createNegated())) {
      falseCopy.push(factory.getConstFactory().getFalse());
      instruction.setFalseReachable();
      states.add(new DfaInstructionState(next, falseCopy));
      if (instruction instanceof InstanceofInstruction && !falseCopy.isNull(dfaLeft)) {
        myUsefulInstanceofs.add((InstanceofInstruction) instruction);
      }
    }

    return states.toArray(new DfaInstructionState[states.size()]);
  }
  private List<DfaMemoryState> addContractResults(
      DfaValue[] argValues,
      MethodContract contract,
      List<DfaMemoryState> states,
      MethodCallInstruction instruction,
      DfaValueFactory factory,
      Set<DfaMemoryState> finalStates) {
    DfaConstValue.Factory constFactory = factory.getConstFactory();
    List<DfaMemoryState> falseStates = ContainerUtil.newArrayList();
    for (int i = 0; i < argValues.length; i++) {
      DfaValue argValue = argValues[i];
      MethodContract.ValueConstraint constraint = contract.arguments[i];
      DfaConstValue expectedValue = constraint.getComparisonValue(factory);
      if (expectedValue == null) continue;

      boolean invertCondition = constraint.shouldUseNonEqComparison();
      DfaValue condition =
          factory
              .getRelationFactory()
              .createRelation(argValue, expectedValue, EQEQ, invertCondition);
      if (condition == null) {
        if (!(argValue instanceof DfaConstValue)) {
          for (DfaMemoryState state : states) {
            falseStates.add(state.createCopy());
          }
          continue;
        }
        condition =
            constFactory.createFromValue(
                (argValue == expectedValue) != invertCondition, PsiType.BOOLEAN, null);
      }

      List<DfaMemoryState> nextStates = ContainerUtil.newArrayList();
      for (DfaMemoryState state : states) {
        boolean unknownVsNull =
            expectedValue == constFactory.getNull()
                && argValue instanceof DfaVariableValue
                && ((DfaMemoryStateImpl) state)
                        .getVariableState((DfaVariableValue) argValue)
                        .getNullability()
                    == Nullness.UNKNOWN;
        DfaMemoryState falseCopy = state.createCopy();
        if (state.applyCondition(condition)) {
          if (unknownVsNull && !invertCondition) {
            state.markEphemeral();
          }
          nextStates.add(state);
        }
        if (falseCopy.applyCondition(condition.createNegated())) {
          if (unknownVsNull && invertCondition) {
            falseCopy.markEphemeral();
          }
          falseStates.add(falseCopy);
        }
      }
      states = nextStates;
    }

    for (DfaMemoryState state : states) {
      state.push(getDfaContractReturnValue(contract, instruction, factory));
      finalStates.add(state);
    }

    return falseStates;
  }