Fix warnings about possible detach of temporary objects

Calling first() or last() on temporary container may
unnecessarily detach the container. Fix it by calling
constFirst() and constLast().

Change-Id: I2460efd5dbee1534eec8a514d9bff2a947bfddf9
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>

src/libs/advanceddockingsystem/dockmanager.cpp

@@ -424,7 +424,7 @@ namespace ADS
         if (areaWidget)
             return addDockWidget(ADS::CenterDockWidgetArea, dockWidget, areaWidget);
         else if (!openedDockAreas().isEmpty())
-            return addDockWidget(area, dockWidget, openedDockAreas().last());
+            return addDockWidget(area, dockWidget, openedDockAreas().constLast());
         else
             return addDockWidget(area, dockWidget, nullptr);
     }

src/plugins/android/androidsettingswidget.cpp

@@ -327,7 +327,8 @@ void AndroidSettingsWidget::updateNdkList()
 
 void AndroidSettingsWidget::addCustomNdkItem()
 {
-    const QString homePath = QStandardPaths::standardLocations(QStandardPaths::HomeLocation).first();
+    const QString homePath = QStandardPaths::standardLocations(QStandardPaths::HomeLocation)
+            .constFirst();
     const QString ndkPath = QFileDialog::getExistingDirectory(this, tr("Select an NDK"), homePath);
 
     if (m_androidConfig.isValidNdk(ndkPath)) {

src/plugins/cpptools/cpptoolsjsextension.cpp

@@ -127,7 +127,7 @@ QString CppToolsJsExtension::includeStatement(
 {
     if (fullyQualifiedClassName.isEmpty())
         return {};
-    const QString className = parts(fullyQualifiedClassName).last();
+    const QString className = parts(fullyQualifiedClassName).constLast();
     if (className.isEmpty() || specialClasses.contains(className))
         return {};
     if (className.startsWith('Q') && className.length() > 2 && className.at(1).isUpper())

src/plugins/debugger/console/consoleview.cpp

@@ -184,7 +184,7 @@ void ConsoleView::onRowActivated(const QModelIndex &index)
         return;
 
     const QFileInfo fi = m_finder.findFile(model()->data(index, ConsoleItem::FileRole).toString())
-            .first().toFileInfo();
+            .constFirst().toFileInfo();
     if (fi.exists() && fi.isFile() && fi.isReadable()) {
         Core::EditorManager::openEditorAt(fi.canonicalFilePath(),
                                           model()->data(index, ConsoleItem::LineRole).toInt());

src/plugins/debugger/qml/qmlengine.cpp

@@ -2447,7 +2447,7 @@ QString QmlEngine::toFileInProject(const QUrl &fileUrl)
     d->fileFinder.setAdditionalSearchDirectories(rp.additionalSearchDirectories);
     d->fileFinder.setSysroot(rp.sysRoot);
 
-    return d->fileFinder.findFile(fileUrl).first().toString();
+    return d->fileFinder.findFile(fileUrl).constFirst().toString();
 }
 
 DebuggerEngine *createQmlEngine()

src/plugins/python/pythonutils.cpp

@@ -197,7 +197,7 @@ static FilePath detectPython(const FilePath &documentPath)
         python = PythonSettings::defaultInterpreter().command;
 
     if (!python.exists() && !PythonSettings::interpreters().isEmpty())
-        python = PythonSettings::interpreters().first().command;
+        python = PythonSettings::interpreters().constFirst().command;
 
     return python;
 }

src/plugins/qmldesigner/components/edit3d/edit3dwidget.cpp

@@ -82,7 +82,7 @@ Edit3DWidget::Edit3DWidget(Edit3DView *view) :
 
                 // Register action as creator command to make it configurable
                 Core::Command *command = Core::ActionManager::registerAction(
-                            action->action(), action->menuId().data(), context);
+                            action->action(), action->menuId().constData(), context);
                 command->setDefaultKeySequence(action->action()->shortcut());
                 command->augmentActionWithShortcutToolTip(action->action());
                 // Clear action shortcut so it doesn't conflict with command's override action

src/plugins/qmldesigner/components/richtexteditor/richtexteditor.cpp

@@ -370,7 +370,7 @@ void RichTextEditor::setupHyperlinkActions()
         if (linkFormat.isAnchor()) {
             m_linkDialog->setLink(linkFormat.anchorHref());
             m_linkDialog->setAnchor(
-                linkFormat.anchorNames().isEmpty() ? QString() : linkFormat.anchorNames().first());
+                linkFormat.anchorNames().isEmpty() ? QString() : linkFormat.anchorNames().constFirst());
         }
         else {
             m_linkDialog->setLink("http://");

src/plugins/qmldesigner/components/timelineeditor/easingcurve.cpp

@@ -192,7 +192,7 @@ QPointF EasingCurve::start() const
 
 QPointF EasingCurve::end() const
 {
-    return toCubicSpline().last();
+    return toCubicSpline().constLast();
 }
 
 QPainterPath EasingCurve::path() const

src/plugins/qmlpreview/qmlpreviewconnectionmanager.cpp

@@ -88,7 +88,7 @@ QUrl QmlPreviewConnectionManager::findValidI18nDirectoryAsUrl(const QString &loc
         auto tryPath = [&](const QString &postfix) {
             url.setPath(path + "/i18n/qml_" + postfix);
             bool success = false;
-            foundPath = m_projectFileFinder.findFile(url, &success).first().toString();
+            foundPath = m_projectFileFinder.findFile(url, &success).constFirst().toString();
             foundPath = foundPath.left(qMax(0, foundPath.lastIndexOf("/i18n")));
             return success;
         };

src/tools/clangbackend/clangbackendmain.cpp

@@ -53,7 +53,7 @@ QString processArguments(QCoreApplication &application)
     if (parser.positionalArguments().isEmpty())
         parser.showHelp(1);
 
-    return parser.positionalArguments().first();
+    return parser.positionalArguments().constFirst();
 }
 
 #ifdef Q_OS_WIN