Widgets: use const (and const APIs) more

For CoW types, prefer const methods to avoid needless detach()ing.

Change-Id: Ia6cad50a10facf6fd4f73d1390edb8642a0aed32
Reviewed-by: Marc Mutz <marc.mutz@kdab.com>

10 files changed, 59 insertions, 59 deletions

diff --git a/src/widgets/graphicsview/qgraphicsanchorlayout_p.cpp b/src/widgets/graphicsview/qgraphicsanchorlayout_p.cpp
index 53db11d2d7..4c01219d87 100644
--- a/src/widgets/graphicsview/qgraphicsanchorlayout_p.cpp
+++ b/src/widgets/graphicsview/qgraphicsanchorlayout_p.cpp
@@ -1082,7 +1082,7 @@ bool QGraphicsAnchorLayoutPrivate::simplifyGraphIteration(QGraphicsAnchorLayoutP
             if (candidates.isEmpty())
                 after = (beforeSequence == adjacents.last() ? adjacents.first() : adjacents.last());
             else
-                after = (candidates.last() == adjacents.last() ? adjacents.first() : adjacents.last());
+                after = (candidates.constLast() == adjacents.last() ? adjacents.first() : adjacents.last());
 
             // ### At this point we assumed that candidates will not contain 'after', this may not hold
             // when simplifying FLOATing anchors.
@@ -1134,9 +1134,9 @@ bool QGraphicsAnchorLayoutPrivate::simplifyGraphIteration(QGraphicsAnchorLayoutP
 
         // One restriction we have is to not simplify half of an anchor and let the other half
         // unsimplified. So we remove center edges before and after the sequence.
-        const AnchorData *firstAnchor = g.edgeData(beforeSequence, candidates.first());
+        const AnchorData *firstAnchor = g.edgeData(beforeSequence, candidates.constFirst());
         if (firstAnchor->isCenterAnchor) {
-            beforeSequence = candidates.first();
+            beforeSequence = candidates.constFirst();
             candidates.remove(0);
 
             // If there's not candidates to be simplified, leave.
@@ -1144,9 +1144,9 @@ bool QGraphicsAnchorLayoutPrivate::simplifyGraphIteration(QGraphicsAnchorLayoutP
                 continue;
         }
 
-        const AnchorData *lastAnchor = g.edgeData(candidates.last(), afterSequence);
+        const AnchorData *lastAnchor = g.edgeData(candidates.constLast(), afterSequence);
         if (lastAnchor->isCenterAnchor) {
-            afterSequence = candidates.last();
+            afterSequence = candidates.constLast();
             candidates.remove(candidates.count() - 1);
 
             if (candidates.isEmpty())
diff --git a/src/widgets/graphicsview/qgraphicsitem.cpp b/src/widgets/graphicsview/qgraphicsitem.cpp
index db683a4e4d..df81d70742 100644
--- a/src/widgets/graphicsview/qgraphicsitem.cpp
+++ b/src/widgets/graphicsview/qgraphicsitem.cpp
@@ -2152,7 +2152,7 @@ bool QGraphicsItem::isBlockedByModalPanel(QGraphicsItem **blockingPanel) const
     if (!blockingPanel)
         blockingPanel = &dummy;
 
-    QGraphicsScenePrivate *scene_d = d_ptr->scene->d_func();
+    const QGraphicsScenePrivate *scene_d = d_ptr->scene->d_func();
     if (scene_d->modalPanels.isEmpty())
         return false;
 
diff --git a/src/widgets/graphicsview/qgraphicsscene.cpp b/src/widgets/graphicsview/qgraphicsscene.cpp
index cb1d1e68d1..b63686cd77 100644
--- a/src/widgets/graphicsview/qgraphicsscene.cpp
+++ b/src/widgets/graphicsview/qgraphicsscene.cpp
@@ -940,7 +940,7 @@ void QGraphicsScenePrivate::grabMouse(QGraphicsItem *item, bool implicit)
 {
     // Append to list of mouse grabber items, and send a mouse grab event.
     if (mouseGrabberItems.contains(item)) {
-        if (mouseGrabberItems.last() == item) {
+        if (mouseGrabberItems.constLast() == item) {
             Q_ASSERT(!implicit);
             if (!lastMouseGrabberItemHasImplicitMouseGrab) {
                 qWarning("QGraphicsItem::grabMouse: already a mouse grabber");
@@ -950,14 +950,14 @@ void QGraphicsScenePrivate::grabMouse(QGraphicsItem *item, bool implicit)
             }
         } else {
             qWarning("QGraphicsItem::grabMouse: already blocked by mouse grabber: %p",
-                     mouseGrabberItems.last());
+                     mouseGrabberItems.constLast());
         }
         return;
     }
 
     // Send ungrab event to the last grabber.
     if (!mouseGrabberItems.isEmpty()) {
-        QGraphicsItem *last = mouseGrabberItems.last();
+        QGraphicsItem *last = mouseGrabberItems.constLast();
         if (lastMouseGrabberItemHasImplicitMouseGrab) {
             // Implicit mouse grab is immediately lost.
             last->ungrabMouse();
@@ -987,12 +987,12 @@ void QGraphicsScenePrivate::ungrabMouse(QGraphicsItem *item, bool itemIsDying)
         return;
     }
 
-    if (item != mouseGrabberItems.last()) {
+    if (item != mouseGrabberItems.constLast()) {
         // Recursively ungrab the next mouse grabber until we reach this item
         // to ensure state consistency.
         ungrabMouse(mouseGrabberItems.at(index + 1), itemIsDying);
     }
-    if (!popupWidgets.isEmpty() && item == popupWidgets.last()) {
+    if (!popupWidgets.isEmpty() && item == popupWidgets.constLast()) {
         // If the item is a popup, go via removePopup to ensure state
         // consistency and that it gets hidden correctly - beware that
         // removePopup() reenters this function to continue removing the grab.
@@ -1017,7 +1017,7 @@ void QGraphicsScenePrivate::ungrabMouse(QGraphicsItem *item, bool itemIsDying)
     // items get a GrabMouse event, but this is a rare case with a simple
     // implementation and it does ensure a consistent state.
     if (!itemIsDying && !mouseGrabberItems.isEmpty()) {
-        QGraphicsItem *last = mouseGrabberItems.last();
+        QGraphicsItem *last = mouseGrabberItems.constLast();
         QEvent event(QEvent::GrabMouse);
         sendEvent(last, &event);
     }
@@ -1039,11 +1039,11 @@ void QGraphicsScenePrivate::clearMouseGrabber()
 void QGraphicsScenePrivate::grabKeyboard(QGraphicsItem *item)
 {
     if (keyboardGrabberItems.contains(item)) {
-        if (keyboardGrabberItems.last() == item)
+        if (keyboardGrabberItems.constLast() == item)
             qWarning("QGraphicsItem::grabKeyboard: already a keyboard grabber");
         else
             qWarning("QGraphicsItem::grabKeyboard: already blocked by keyboard grabber: %p",
-                     keyboardGrabberItems.last());
+                     keyboardGrabberItems.constLast());
         return;
     }
 
@@ -1051,7 +1051,7 @@ void QGraphicsScenePrivate::grabKeyboard(QGraphicsItem *item)
     if (!keyboardGrabberItems.isEmpty()) {
         // Just send ungrab event to current grabber.
         QEvent ungrabEvent(QEvent::UngrabKeyboard);
-        sendEvent(keyboardGrabberItems.last(), &ungrabEvent);
+        sendEvent(keyboardGrabberItems.constLast(), &ungrabEvent);
     }
 
     keyboardGrabberItems << item;
@@ -1071,7 +1071,7 @@ void QGraphicsScenePrivate::ungrabKeyboard(QGraphicsItem *item, bool itemIsDying
         qWarning("QGraphicsItem::ungrabKeyboard: not a keyboard grabber");
         return;
     }
-    if (item != keyboardGrabberItems.last()) {
+    if (item != keyboardGrabberItems.constLast()) {
         // Recursively ungrab the topmost keyboard grabber until we reach this
         // item to ensure state consistency.
         ungrabKeyboard(keyboardGrabberItems.at(index + 1), itemIsDying);
@@ -1088,7 +1088,7 @@ void QGraphicsScenePrivate::ungrabKeyboard(QGraphicsItem *item, bool itemIsDying
 
     // Send notification about mouse regrab.
     if (!itemIsDying && !keyboardGrabberItems.isEmpty()) {
-        QGraphicsItem *last = keyboardGrabberItems.last();
+        QGraphicsItem *last = keyboardGrabberItems.constLast();
         QEvent event(QEvent::GrabKeyboard);
         sendEvent(last, &event);
     }
@@ -1100,7 +1100,7 @@ void QGraphicsScenePrivate::ungrabKeyboard(QGraphicsItem *item, bool itemIsDying
 void QGraphicsScenePrivate::clearKeyboardGrabber()
 {
     if (!keyboardGrabberItems.isEmpty())
-        ungrabKeyboard(keyboardGrabberItems.first());
+        ungrabKeyboard(keyboardGrabberItems.constFirst());
 }
 
 void QGraphicsScenePrivate::enableMouseTrackingOnViews()
@@ -1142,8 +1142,8 @@ void QGraphicsScenePrivate::storeMouseButtonsForMouseGrabber(QGraphicsSceneMouse
     for (int i = 0x1; i <= 0x10; i <<= 1) {
         if (event->buttons() & i) {
             mouseGrabberButtonDownPos.insert(Qt::MouseButton(i),
-                                             mouseGrabberItems.last()->d_ptr->genericMapFromScene(event->scenePos(),
-                                                                                                  event->widget()));
+                                             mouseGrabberItems.constLast()->d_ptr->genericMapFromScene(event->scenePos(),
+                                                                                                       event->widget()));
             mouseGrabberButtonDownScenePos.insert(Qt::MouseButton(i), event->scenePos());
             mouseGrabberButtonDownScreenPos.insert(Qt::MouseButton(i), event->screenPos());
         }
@@ -1308,7 +1308,7 @@ void QGraphicsScenePrivate::sendMouseEvent(QGraphicsSceneMouseEvent *mouseEvent)
         return;
     }
 
-    QGraphicsItem *item = mouseGrabberItems.last();
+    QGraphicsItem *item = mouseGrabberItems.constLast();
     if (item->isBlockedByModalPanel())
         return;
 
@@ -1335,7 +1335,7 @@ void QGraphicsScenePrivate::mousePressEventHandler(QGraphicsSceneMouseEvent *mou
 
     // Deliver to any existing mouse grabber.
     if (!mouseGrabberItems.isEmpty()) {
-        if (mouseGrabberItems.last()->isBlockedByModalPanel())
+        if (mouseGrabberItems.constLast()->isBlockedByModalPanel())
             return;
         // The event is ignored by default, but we disregard the event's
         // accepted state after delivery; the mouse is grabbed, after all.
@@ -1401,7 +1401,7 @@ void QGraphicsScenePrivate::mousePressEventHandler(QGraphicsSceneMouseEvent *mou
 
     // Any item will do.
     if (sceneModality && cachedItemsUnderMouse.isEmpty())
-        cachedItemsUnderMouse << modalPanels.first();
+        cachedItemsUnderMouse << modalPanels.constFirst();
 
     // Find a mouse grabber by sending mouse press events to all mouse grabber
     // candidates one at a time, until the event is accepted. It's accepted by
@@ -1450,7 +1450,7 @@ void QGraphicsScenePrivate::mousePressEventHandler(QGraphicsSceneMouseEvent *mou
             sendMouseEvent(mouseEvent);
         }
 
-        bool dontSendUngrabEvents = mouseGrabberItems.isEmpty() || mouseGrabberItems.last() != item;
+        bool dontSendUngrabEvents = mouseGrabberItems.isEmpty() || mouseGrabberItems.constLast() != item;
         if (disabled) {
             ungrabMouse(item, /* itemIsDying = */ dontSendUngrabEvents);
             break;
@@ -2167,8 +2167,8 @@ QList<QGraphicsItem *> QGraphicsScene::collidingItems(const QGraphicsItem *item,
 */
 QGraphicsItem *QGraphicsScene::itemAt(const QPointF &position, const QTransform &deviceTransform) const
 {
-    QList<QGraphicsItem *> itemsAtPoint = items(position, Qt::IntersectsItemShape,
-                                                Qt::DescendingOrder, deviceTransform);
+    const QList<QGraphicsItem *> itemsAtPoint = items(position, Qt::IntersectsItemShape,
+                                                      Qt::DescendingOrder, deviceTransform);
     return itemsAtPoint.isEmpty() ? 0 : itemsAtPoint.first();
 }
 
@@ -3771,7 +3771,7 @@ void QGraphicsScene::focusOutEvent(QFocusEvent *focusEvent)
 
     // Remove all popups when the scene loses focus.
     if (!d->popupWidgets.isEmpty())
-        d->removePopup(d->popupWidgets.first());
+        d->removePopup(d->popupWidgets.constFirst());
 }
 
 /*!
@@ -3868,7 +3868,7 @@ bool QGraphicsScenePrivate::dispatchHoverEvent(QGraphicsSceneHoverEvent *hoverEv
 
     // Find the common ancestor item for the new topmost hoverItem and the
     // last item in the hoverItem list.
-    QGraphicsItem *commonAncestorItem = (item && !hoverItems.isEmpty()) ? item->commonAncestorItem(hoverItems.last()) : 0;
+    QGraphicsItem *commonAncestorItem = (item && !hoverItems.isEmpty()) ? item->commonAncestorItem(hoverItems.constLast()) : 0;
     while (commonAncestorItem && !itemAcceptsHoverEvents_helper(commonAncestorItem))
         commonAncestorItem = commonAncestorItem->parentItem();
     if (commonAncestorItem && commonAncestorItem->panel() != item->panel()) {
@@ -3909,7 +3909,7 @@ bool QGraphicsScenePrivate::dispatchHoverEvent(QGraphicsSceneHoverEvent *hoverEv
     // Generate a move event for the item itself
     if (item
         && !hoverItems.isEmpty()
-        && item == hoverItems.last()) {
+        && item == hoverItems.constLast()) {
         sendHoverEvent(QEvent::GraphicsSceneHoverMove, item, hoverEvent);
         return true;
     }
@@ -3959,7 +3959,7 @@ void QGraphicsScene::keyPressEvent(QKeyEvent *keyEvent)
     // ### Merge this function with keyReleaseEvent; they are identical
     // ### (except this comment).
     Q_D(QGraphicsScene);
-    QGraphicsItem *item = !d->keyboardGrabberItems.isEmpty() ? d->keyboardGrabberItems.last() : 0;
+    QGraphicsItem *item = !d->keyboardGrabberItems.isEmpty() ? d->keyboardGrabberItems.constLast() : 0;
     if (!item)
         item = focusItem();
     if (item) {
@@ -3991,7 +3991,7 @@ void QGraphicsScene::keyReleaseEvent(QKeyEvent *keyEvent)
     // ### Merge this function with keyPressEvent; they are identical (except
     // ### this comment).
     Q_D(QGraphicsScene);
-    QGraphicsItem *item = !d->keyboardGrabberItems.isEmpty() ? d->keyboardGrabberItems.last() : 0;
+    QGraphicsItem *item = !d->keyboardGrabberItems.isEmpty() ? d->keyboardGrabberItems.constLast() : 0;
     if (!item)
         item = focusItem();
     if (item) {
@@ -4100,9 +4100,9 @@ void QGraphicsScene::mouseReleaseEvent(QGraphicsSceneMouseEvent *mouseEvent)
     // Reset the mouse grabber when the last mouse button has been released.
     if (!mouseEvent->buttons()) {
         if (!d->mouseGrabberItems.isEmpty()) {
-            d->lastMouseGrabberItem = d->mouseGrabberItems.last();
+            d->lastMouseGrabberItem = d->mouseGrabberItems.constLast();
             if (d->lastMouseGrabberItemHasImplicitMouseGrab)
-                d->mouseGrabberItems.last()->ungrabMouse();
+                d->mouseGrabberItems.constLast()->ungrabMouse();
         } else {
             d->lastMouseGrabberItem = 0;
         }
@@ -5901,7 +5901,7 @@ void QGraphicsScenePrivate::touchEventHandler(QTouchEvent *sceneTouchEvent)
                 cachedItemsUnderMouse = itemsAtPosition(touchPoint.screenPos().toPoint(),
                                                         touchPoint.scenePos(),
                                                         static_cast<QWidget *>(sceneTouchEvent->target()));
-                item = cachedItemsUnderMouse.isEmpty() ? 0 : cachedItemsUnderMouse.first();
+                item = cachedItemsUnderMouse.isEmpty() ? 0 : cachedItemsUnderMouse.constFirst();
             }
 
             if (sceneTouchEvent->device()->type() == QTouchDevice::TouchScreen) {
@@ -6012,7 +6012,7 @@ bool QGraphicsScenePrivate::sendTouchBeginEvent(QGraphicsItem *origin, QTouchEve
 {
     Q_Q(QGraphicsScene);
 
-    if (cachedItemsUnderMouse.isEmpty() || cachedItemsUnderMouse.first() != origin) {
+    if (cachedItemsUnderMouse.isEmpty() || cachedItemsUnderMouse.constFirst() != origin) {
         const QTouchEvent::TouchPoint &firstTouchPoint = touchEvent->touchPoints().first();
         cachedItemsUnderMouse = itemsAtPosition(firstTouchPoint.screenPos().toPoint(),
                                                 firstTouchPoint.scenePos(),
@@ -6128,7 +6128,7 @@ void QGraphicsScenePrivate::enterModal(QGraphicsItem *panel, QGraphicsItem::Pane
     }
 
     if (!mouseGrabberItems.isEmpty() && lastMouseGrabberItemHasImplicitMouseGrab) {
-        QGraphicsItem *item = mouseGrabberItems.last();
+        QGraphicsItem *item = mouseGrabberItems.constLast();
         if (item->isBlockedByModalPanel())
             ungrabMouse(item, /*itemIsDying =*/ false);
     }
diff --git a/src/widgets/graphicsview/qgraphicsview.cpp b/src/widgets/graphicsview/qgraphicsview.cpp
index fc5dbdd80a..442918169a 100644
--- a/src/widgets/graphicsview/qgraphicsview.cpp
+++ b/src/widgets/graphicsview/qgraphicsview.cpp
@@ -2378,7 +2378,7 @@ QGraphicsItem *QGraphicsView::itemAt(const QPoint &pos) const
     Q_D(const QGraphicsView);
     if (!d->scene)
         return 0;
-    QList<QGraphicsItem *> itemsAtPos = items(pos);
+    const QList<QGraphicsItem *> itemsAtPos = items(pos);
     return itemsAtPos.isEmpty() ? 0 : itemsAtPos.first();
 }
 
@@ -2865,7 +2865,7 @@ bool QGraphicsView::viewportEvent(QEvent *event)
         // the mouse grab.
         // Remove all popups when the scene loses focus.
         if (!d->scene->d_func()->popupWidgets.isEmpty())
-            d->scene->d_func()->removePopup(d->scene->d_func()->popupWidgets.first());
+            d->scene->d_func()->removePopup(d->scene->d_func()->popupWidgets.constFirst());
         QApplication::sendEvent(d->scene, event);
         break;
     case QEvent::Show:
@@ -2889,7 +2889,7 @@ bool QGraphicsView::viewportEvent(QEvent *event)
             || (QApplication::activeModalWidget() && QApplication::activeModalWidget() != window())
             || (QApplication::activeWindow() != window())) {
             if (!d->scene->d_func()->popupWidgets.isEmpty())
-                d->scene->d_func()->removePopup(d->scene->d_func()->popupWidgets.first());
+                d->scene->d_func()->removePopup(d->scene->d_func()->popupWidgets.constFirst());
         }
         d->useLastMouseEvent = false;
         // a hack to pass a viewport pointer to the scene inside the leave event
diff --git a/src/widgets/itemviews/qcolumnview.cpp b/src/widgets/itemviews/qcolumnview.cpp
index 26173b5e92..6c7c914bc0 100644
--- a/src/widgets/itemviews/qcolumnview.cpp
+++ b/src/widgets/itemviews/qcolumnview.cpp
@@ -412,9 +412,9 @@ void QColumnViewPrivate::updateScrollbars()
     // find the total horizontal length of the laid out columns
     int horizontalLength = 0;
     if (!columns.isEmpty()) {
-        horizontalLength = (columns.last()->x() + columns.last()->width()) - columns.first()->x();
+        horizontalLength = (columns.constLast()->x() + columns.constLast()->width()) - columns.constFirst()->x();
         if (horizontalLength <= 0) // reverse mode
-            horizontalLength = (columns.first()->x() + columns.first()->width()) - columns.last()->x();
+            horizontalLength = (columns.constFirst()->x() + columns.constFirst()->width()) - columns.constLast()->x();
     }
 
     QSize viewportSize = viewport->size();
@@ -629,7 +629,7 @@ void QColumnViewPrivate::closeColumns(const QModelIndex &parent, bool build)
     while (!dirsToAppend.isEmpty()) {
         QAbstractItemView *newView = createColumn(dirsToAppend.takeLast(), true);
         if (!dirsToAppend.isEmpty())
-            newView->setCurrentIndex(dirsToAppend.last());
+            newView->setCurrentIndex(dirsToAppend.constLast());
     }
 
     if (build && !alreadyExists)
@@ -713,8 +713,8 @@ QAbstractItemView *QColumnViewPrivate::createColumn(const QModelIndex &index, bo
         columnSizes.resize(qMax(columnSizes.count(), columns.count() + 1));
         columnSizes[columns.count()] = initialWidth;
     }
-    if (!columns.isEmpty() && columns.last()->isHidden())
-        columns.last()->setVisible(true);
+    if (!columns.isEmpty() && columns.constLast()->isHidden())
+        columns.constLast()->setVisible(true);
 
     columns.append(view);
     doLayout();
@@ -835,7 +835,7 @@ void QColumnViewPrivate::setPreviewWidget(QWidget *widget)
 {
     Q_Q(QColumnView);
     if (previewColumn) {
-        if (!columns.isEmpty() && columns.last() == previewColumn)
+        if (!columns.isEmpty() && columns.constLast() == previewColumn)
             columns.removeLast();
         previewColumn->deleteLater();
     }
@@ -1003,11 +1003,11 @@ void QColumnViewPrivate::_q_changeCurrentColumn()
             parentColumn->setCurrentIndex(current.parent());
     }
 
-    if (columns.last()->isHidden()) {
-        columns.last()->setVisible(true);
+    if (columns.constLast()->isHidden()) {
+        columns.constLast()->setVisible(true);
     }
-    if (columns.last()->selectionModel())
-        columns.last()->selectionModel()->clear();
+    if (columns.constLast()->selectionModel())
+        columns.constLast()->selectionModel()->clear();
     updateScrollbars();
 }
 
diff --git a/src/widgets/itemviews/qdirmodel.cpp b/src/widgets/itemviews/qdirmodel.cpp
index dfb1d7619e..58e586980f 100644
--- a/src/widgets/itemviews/qdirmodel.cpp
+++ b/src/widgets/itemviews/qdirmodel.cpp
@@ -885,7 +885,7 @@ QModelIndex QDirModel::index(const QString &path, int column) const
 
 #if defined(Q_OS_WIN) && !defined(Q_OS_WINCE)
     if (absolutePath.startsWith(QLatin1String("//"))) { // UNC path
-        QString host = pathElements.first();
+        QString host = pathElements.constFirst();
         int r = 0;
         for (; r < d->root.children.count(); ++r)
             if (d->root.children.at(r).info.fileName() == host)
diff --git a/src/widgets/itemviews/qlistview.cpp b/src/widgets/itemviews/qlistview.cpp
index 3303aac6ed..0788e0287a 100644
--- a/src/widgets/itemviews/qlistview.cpp
+++ b/src/widgets/itemviews/qlistview.cpp
@@ -2396,9 +2396,9 @@ QPoint QListModeViewBase::initStaticLayout(const QListViewLayoutInfo &info)
     } else if (info.wrap) {
         if (info.flow == QListView::LeftToRight) {
             x = batchSavedPosition;
-            y = segmentPositions.last();
+            y = segmentPositions.constLast();
         } else { // flow == QListView::TopToBottom
-            x = segmentPositions.last();
+            x = segmentPositions.constLast();
             y = batchSavedPosition;
         }
     } else { // not first and not wrap
@@ -2613,7 +2613,7 @@ int QListModeViewBase::perItemScrollingPageSteps(int length, int bounds, bool wr
     int steps = positions.count() - 1;
     int max = qMax(length, bounds);
     int min = qMin(length, bounds);
-    int pos = min - (max - positions.last());
+    int pos = min - (max - positions.constLast());
 
     while (pos >= 0 && steps > 0) {
         pos -= (positions.at(steps) - positions.at(steps - 1));
diff --git a/src/widgets/itemviews/qtreeview.cpp b/src/widgets/itemviews/qtreeview.cpp
index b6fd9f8ba8..4ce7da0229 100644
--- a/src/widgets/itemviews/qtreeview.cpp
+++ b/src/widgets/itemviews/qtreeview.cpp
@@ -2357,10 +2357,10 @@ void QTreeView::setSelection(const QRect &rect, QItemSelectionModel::SelectionFl
         return;
     }
     if (!topLeft.isValid() && !d->viewItems.isEmpty())
-        topLeft = d->viewItems.first().index;
+        topLeft = d->viewItems.constFirst().index;
     if (!bottomRight.isValid() && !d->viewItems.isEmpty()) {
         const int column = d->header->logicalIndex(d->header->count() - 1);
-        const QModelIndex index = d->viewItems.last().index;
+        const QModelIndex index = d->viewItems.constLast().index;
         bottomRight = index.sibling(index.row(), column);
     }
 
@@ -2668,9 +2668,9 @@ void QTreeView::selectAll()
     SelectionMode mode = d->selectionMode;
     d->executePostedLayout(); //make sure we lay out the items
     if (mode != SingleSelection && mode != NoSelection && !d->viewItems.isEmpty()) {
-        const QModelIndex &idx = d->viewItems.last().index;
+        const QModelIndex &idx = d->viewItems.constLast().index;
         QModelIndex lastItemIndex = idx.sibling(idx.row(), d->model->columnCount(idx.parent()) - 1);
-        d->select(d->viewItems.first().index, lastItemIndex,
+        d->select(d->viewItems.constFirst().index, lastItemIndex,
                   QItemSelectionModel::ClearAndSelect
                   |QItemSelectionModel::Rows);
     }
diff --git a/src/widgets/widgets/qdockarealayout.cpp b/src/widgets/widgets/qdockarealayout.cpp
index ed630913e7..fd155bf156 100644
--- a/src/widgets/widgets/qdockarealayout.cpp
+++ b/src/widgets/widgets/qdockarealayout.cpp
@@ -3163,7 +3163,7 @@ void QDockAreaLayout::splitDockWidget(QDockWidget *after,
                                                QDockWidget *dockWidget,
                                                Qt::Orientation orientation)
 {
-    QList<int> path = indexOf(after);
+    const QList<int> path = indexOf(after);
     if (path.isEmpty())
         return;
 
diff --git a/src/widgets/widgets/qfontcombobox.cpp b/src/widgets/widgets/qfontcombobox.cpp
index 1d736c8e96..9bd33409ae 100644
--- a/src/widgets/widgets/qfontcombobox.cpp
+++ b/src/widgets/widgets/qfontcombobox.cpp
@@ -162,7 +162,7 @@ static QFontDatabase::WritingSystem writingSystemForFont(const QFont &font, bool
         return QFontDatabase::TraditionalChinese;
     }
 
-    system = writingSystems.last();
+    system = writingSystems.constLast();
 
     if (!*hasLatin) {
         // we need to show something