message: Fix possible nullptr exception in FlowLayout
diff: @@ -177,15 +177,15 @@ int FlowLayout::doLayout(const QRect &rect, bool testOnly) const
  //! [10]
  for (QLayoutItem *item : qAsConst(itemList)) {
  - const QWidget *wid = item->widget();
  int spaceX = horizontalSpacing();
  + int spaceY = verticalSpacing();
  if (spaceX == -1)
  - spaceX = wid->style()->layoutSpacing(
  + spaceX = QApplication::style()->layoutSpacing(
  QSizePolicy::PushButton, QSizePolicy::PushButton, Qt::Horizontal);
  - int spaceY = verticalSpacing();
  if (spaceY == -1)
  - spaceY = wid->style()->layoutSpacing(
  + spaceY = QApplication::style()->layoutSpacing(
  QSizePolicy::PushButton, QSizePolicy::PushButton, Qt::Vertical);
  +
  //! [10]
  //! [11]
  int nextX = x + item->sizeHint().width() + spaceX;
  