public DfaInstructionState[] visitMethodCall(
      MethodCallInstruction instruction, DataFlowRunner runner, DfaMemoryState memState) {
    //noinspection UnusedDeclaration
    for (PsiExpression arg : instruction.getArgs()) {
      memState.pop();
    }

    memState.pop(); // qualifier
    memState.push(DfaUnknownValue.getInstance());
    return nextInstruction(instruction, runner, memState);
  }
  @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;
  }