@Nullable
  private DfaValue[] popCallArguments(
      MethodCallInstruction instruction, DataFlowRunner runner, DfaMemoryState memState) {
    final PsiExpression[] args = instruction.getArgs();

    PsiMethod method = instruction.getTargetMethod();
    boolean varargCall = instruction.isVarArgCall();
    DfaValue[] argValues;
    if (method == null || instruction.getContracts().isEmpty()) {
      argValues = null;
    } else {
      int paramCount = method.getParameterList().getParametersCount();
      if (paramCount == args.length || method.isVarArgs() && args.length >= paramCount - 1) {
        argValues = new DfaValue[paramCount];
        if (varargCall) {
          argValues[paramCount - 1] = DfaUnknownValue.getInstance();
        }
      } else {
        argValues = null;
      }
    }

    for (int i = 0; i < args.length; i++) {
      final DfaValue arg = memState.pop();
      int paramIndex = args.length - i - 1;
      if (argValues != null && (paramIndex < argValues.length - 1 || !varargCall)) {
        argValues[paramIndex] = arg;
      }

      PsiExpression expr = args[paramIndex];
      Nullness requiredNullability = instruction.getArgRequiredNullability(expr);
      if (requiredNullability == Nullness.NOT_NULL) {
        if (!checkNotNullable(
            memState, arg, NullabilityProblem.passingNullableToNotNullParameter, expr)) {
          forceNotNull(runner, memState, arg);
        }
      } else if (requiredNullability == Nullness.UNKNOWN) {
        checkNotNullable(
            memState, arg, NullabilityProblem.passingNullableArgumentToNonAnnotatedParameter, expr);
      }
    }
    return argValues;
  }
  @Override
  public DfaInstructionState[] visitMethodCall(
      final MethodCallInstruction instruction,
      final DataFlowRunner runner,
      final DfaMemoryState memState) {
    DfaValue[] argValues = popCallArguments(instruction, runner, memState);
    final DfaValue qualifier = popQualifier(instruction, runner, memState);

    List<DfaMemoryState> currentStates = ContainerUtil.newArrayList(memState);
    Set<DfaMemoryState> finalStates = ContainerUtil.newLinkedHashSet();
    if (argValues != null) {
      for (MethodContract contract : instruction.getContracts()) {
        currentStates =
            addContractResults(
                argValues, contract, currentStates, instruction, runner.getFactory(), finalStates);
      }
    }
    for (DfaMemoryState state : currentStates) {
      state.push(getMethodResultValue(instruction, qualifier, runner.getFactory()));
      finalStates.add(state);
    }

    return ContainerUtil.map2Array(
        finalStates,
        DfaInstructionState.class,
        new Function<DfaMemoryState, DfaInstructionState>() {
          @Override
          public DfaInstructionState fun(DfaMemoryState state) {
            if (instruction.shouldFlushFields()) {
              state.flushFields();
            }
            return new DfaInstructionState(
                runner.getInstruction(instruction.getIndex() + 1), state);
          }
        });
  }