Small performance improvements suggested by clang-tidy

mostly add const &, a few std::move and in particular case, remove const
so the std::move being done over the variable actually has effect

Change-Id: Id611cd31bc012f219d7a17d4626b1c2a5fbddd66
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>

32 files changed, 51 insertions, 50 deletions

diff --git a/src/particles/qquickcustomaffector.cpp b/src/particles/qquickcustomaffector.cpp
index cadd2992b1..5e2133dfaf 100644
--- a/src/particles/qquickcustomaffector.cpp
+++ b/src/particles/qquickcustomaffector.cpp
@@ -233,7 +233,7 @@ bool QQuickCustomAffector::affectParticle(QQuickParticleData *d, qreal dt)
     return changed;
 }
 
-void QQuickCustomAffector::affectProperties(const QList<QQuickParticleData*> particles, qreal dt)
+void QQuickCustomAffector::affectProperties(const QList<QQuickParticleData*> &particles, qreal dt)
 {
     foreach (QQuickParticleData* d, particles)
         if ( affectParticle(d, dt) )
diff --git a/src/particles/qquickcustomaffector_p.h b/src/particles/qquickcustomaffector_p.h
index 10db70d71d..5b1ea55659 100644
--- a/src/particles/qquickcustomaffector_p.h
+++ b/src/particles/qquickcustomaffector_p.h
@@ -156,7 +156,7 @@ protected:
     bool affectParticle(QQuickParticleData *d, qreal dt) override;
 
 private:
-    void affectProperties(const QList<QQuickParticleData*> particles, qreal dt);
+    void affectProperties(const QList<QQuickParticleData*> &particles, qreal dt);
     QQuickDirection * m_position;
     QQuickDirection * m_velocity;
     QQuickDirection * m_acceleration;
diff --git a/src/particles/qquickmaskextruder.cpp b/src/particles/qquickmaskextruder.cpp
index 4c5d9e9d88..2ce3650743 100644
--- a/src/particles/qquickmaskextruder.cpp
+++ b/src/particles/qquickmaskextruder.cpp
@@ -68,14 +68,14 @@ QQuickMaskExtruder::QQuickMaskExtruder(QObject *parent) :
 {
 }
 
-void QQuickMaskExtruder::setSource(QUrl arg)
+void QQuickMaskExtruder::setSource(const QUrl &arg)
 {
     if (m_source != arg) {
         m_source = arg;
 
         m_lastHeight = -1;//Trigger reset
         m_lastWidth = -1;
-        emit sourceChanged(arg);
+        emit sourceChanged(m_source);
         startMaskLoading();
     }
 }
diff --git a/src/particles/qquickmaskextruder_p.h b/src/particles/qquickmaskextruder_p.h
index 0fc0331db8..bbb61b0d28 100644
--- a/src/particles/qquickmaskextruder_p.h
+++ b/src/particles/qquickmaskextruder_p.h
@@ -73,10 +73,10 @@ public:
 
 Q_SIGNALS:
 
-    void sourceChanged(QUrl arg);
+    void sourceChanged(const QUrl &arg);
 
 public Q_SLOTS:
-    void setSource(QUrl arg);
+    void setSource(const QUrl &arg);
 
 private Q_SLOTS:
     void startMaskLoading();
diff --git a/src/plugins/qmltooling/qmldbg_server/qqmldebugserver.cpp b/src/plugins/qmltooling/qmldbg_server/qqmldebugserver.cpp
index 2d5282b48c..cc663cd6b3 100644
--- a/src/plugins/qmltooling/qmldbg_server/qqmldebugserver.cpp
+++ b/src/plugins/qmltooling/qmldbg_server/qqmldebugserver.cpp
@@ -506,7 +506,7 @@ void QQmlDebugServerImpl::receiveMessage()
             in >> m_clientPlugins;
 
             for (DebugServiceConstIt iter = m_plugins.constBegin(), cend = m_plugins.constEnd(); iter != cend; ++iter) {
-                const QString pluginName = iter.key();
+                const QString &pluginName = iter.key();
                 QQmlDebugService::State newState = QQmlDebugService::Unavailable;
                 if (m_clientPlugins.contains(pluginName))
                     newState = QQmlDebugService::Enabled;
diff --git a/src/qml/compiler/qqmlirbuilder.cpp b/src/qml/compiler/qqmlirbuilder.cpp
index 171dc641d3..665d2633a7 100644
--- a/src/qml/compiler/qqmlirbuilder.cpp
+++ b/src/qml/compiler/qqmlirbuilder.cpp
@@ -964,7 +964,7 @@ QStringRef IRBuilder::asStringRef(QQmlJS::AST::Node *node)
     return textRefAt(node->firstSourceLocation(), node->lastSourceLocation());
 }
 
-void IRBuilder::extractVersion(QStringRef string, int *maj, int *min)
+void IRBuilder::extractVersion(const QStringRef &string, int *maj, int *min)
 {
     *maj = -1; *min = -1;
 
diff --git a/src/qml/compiler/qqmlirbuilder_p.h b/src/qml/compiler/qqmlirbuilder_p.h
index c366c8e459..4279f5b768 100644
--- a/src/qml/compiler/qqmlirbuilder_p.h
+++ b/src/qml/compiler/qqmlirbuilder_p.h
@@ -453,7 +453,7 @@ public:
 
     static QString asString(QQmlJS::AST::UiQualifiedId *node);
     QStringRef asStringRef(QQmlJS::AST::Node *node);
-    static void extractVersion(QStringRef string, int *maj, int *min);
+    static void extractVersion(const QStringRef &string, int *maj, int *min);
     QStringRef textRefAt(const QQmlJS::AST::SourceLocation &loc) const
     { return QStringRef(&sourceCode, loc.offset, loc.length); }
     QStringRef textRefAt(const QQmlJS::AST::SourceLocation &first,
diff --git a/src/qml/qml/qqmlcontext.cpp b/src/qml/qml/qqmlcontext.cpp
index 14892bd6ad..af8deb085c 100644
--- a/src/qml/qml/qqmlcontext.cpp
+++ b/src/qml/qml/qqmlcontext.cpp
@@ -358,7 +358,7 @@ void QQmlContext::setContextProperties(const QVector<PropertyPair> &properties)
     data->expressions = nullptr;
     data->childContexts = nullptr;
 
-    for (auto property : properties)
+    for (const auto &property : properties)
         setContextProperty(property.name, property.value);
 
     data->expressions = expressions;
diff --git a/src/qml/qml/qqmldatablob.cpp b/src/qml/qml/qqmldatablob.cpp
index 2183721d32..750fc6de50 100644
--- a/src/qml/qml/qqmldatablob.cpp
+++ b/src/qml/qml/qqmldatablob.cpp
@@ -351,7 +351,7 @@ void QQmlDataBlob::addDependency(QQmlDataBlob *blob)
         status() == Error || status() == Complete || m_isDone)
         return;
 
-    for (auto existingDep: qAsConst(m_waitingFor))
+    for (const auto &existingDep: qAsConst(m_waitingFor))
         if (existingDep.data() == blob)
             return;
 
diff --git a/src/qml/qml/qqmldirdata.cpp b/src/qml/qml/qqmldirdata.cpp
index 7652cec322..de74dfdf9b 100644
--- a/src/qml/qml/qqmldirdata.cpp
+++ b/src/qml/qml/qqmldirdata.cpp
@@ -61,7 +61,7 @@ QQmlTypeLoader::Blob::PendingImportPtr QQmlQmldirData::import(QQmlTypeLoader::Bl
 
 void QQmlQmldirData::setImport(QQmlTypeLoader::Blob *blob, QQmlTypeLoader::Blob::PendingImportPtr import)
 {
-    m_imports[blob] = import;
+    m_imports[blob] = std::move(import);
 }
 
 int QQmlQmldirData::priority(QQmlTypeLoader::Blob *blob) const
diff --git a/src/qml/qml/qqmlmetatypedata.cpp b/src/qml/qml/qqmlmetatypedata.cpp
index 41a7778da3..775bc8bdb4 100644
--- a/src/qml/qml/qqmlmetatypedata.cpp
+++ b/src/qml/qml/qqmlmetatypedata.cpp
@@ -150,7 +150,7 @@ QQmlPropertyCache *QQmlMetaTypeData::propertyCache(const QQmlType &type, int min
     bool hasCopied = false;
 
     for (int ii = 0; ii < types.count(); ++ii) {
-        QQmlType currentType = types.at(ii);
+        const QQmlType &currentType = types.at(ii);
         if (!currentType.isValid())
             continue;
 
diff --git a/src/qml/qml/qqmltype.cpp b/src/qml/qml/qqmltype.cpp
index 3615749da1..2db3ad6b2a 100644
--- a/src/qml/qml/qqmltype.cpp
+++ b/src/qml/qml/qqmltype.cpp
@@ -393,7 +393,7 @@ void QQmlTypePrivate::createEnumConflictReport(const QMetaObject *metaObject, co
 
     qWarning().noquote() << QLatin1String("Possible conflicting items:");
     // find items with conflicting key
-    for (const auto i : enumInfoList) {
+    for (const auto &i : qAsConst(enumInfoList)) {
         if (i.enumKey == conflictingKey)
         qWarning().noquote().nospace() << "    " << i.metaObjectName << "." << i.enumName << "." << i.enumKey << " from scope "
                                            << i.metaEnumScope << " injected by " << i.path.join(QLatin1String("->"));
diff --git a/src/qml/qml/qqmltypeloader.cpp b/src/qml/qml/qqmltypeloader.cpp
index 42e7d2c4b4..62007effdd 100644
--- a/src/qml/qml/qqmltypeloader.cpp
+++ b/src/qml/qml/qqmltypeloader.cpp
@@ -491,7 +491,7 @@ bool QQmlTypeLoader::Blob::fetchQmldir(const QUrl &url, PendingImportPtr import,
 {
     QQmlRefPointer<QQmlQmldirData> data = typeLoader()->getQmldir(url);
 
-    data->setImport(this, import);
+    data->setImport(this, std::move(import));
     data->setPriority(this, priority);
 
     if (data->status() == Error) {
diff --git a/src/qml/qml/qqmltypeloaderqmldircontent.cpp b/src/qml/qml/qqmltypeloaderqmldircontent.cpp
index 238af9b710..8e983db756 100644
--- a/src/qml/qml/qqmltypeloaderqmldircontent.cpp
+++ b/src/qml/qml/qqmltypeloaderqmldircontent.cpp
@@ -55,7 +55,8 @@ QList<QQmlError> QQmlTypeLoaderQmldirContent::errors(const QString &uri) const
 {
     QList<QQmlError> errors;
     const QUrl url(uri);
-    for (const auto parseError : m_parser.errors(uri)) {
+    const auto parseErrors = m_parser.errors(uri);
+    for (const auto &parseError : parseErrors) {
         QQmlError error;
         error.setUrl(url);
         error.setLine(parseError.line);
diff --git a/src/quick/handlers/qquickmultipointhandler.cpp b/src/quick/handlers/qquickmultipointhandler.cpp
index 0afc9997aa..f404788de4 100644
--- a/src/quick/handlers/qquickmultipointhandler.cpp
+++ b/src/quick/handlers/qquickmultipointhandler.cpp
@@ -364,7 +364,7 @@ void QQuickMultiPointHandler::acceptPoints(const QVector<QQuickEventPoint *> &po
         point->setAccepted();
 }
 
-bool QQuickMultiPointHandler::grabPoints(QVector<QQuickEventPoint *> points)
+bool QQuickMultiPointHandler::grabPoints(const QVector<QQuickEventPoint *> &points)
 {
     if (points.isEmpty())
         return false;
diff --git a/src/quick/handlers/qquickmultipointhandler_p.h b/src/quick/handlers/qquickmultipointhandler_p.h
index eeb4b13b83..480f69035b 100644
--- a/src/quick/handlers/qquickmultipointhandler_p.h
+++ b/src/quick/handlers/qquickmultipointhandler_p.h
@@ -107,7 +107,7 @@ protected:
     QVector<PointData> angles(const QPointF &ref) const;
     static qreal averageAngleDelta(const QVector<PointData> &old, const QVector<PointData> &newAngles);
     void acceptPoints(const QVector<QQuickEventPoint *> &points);
-    bool grabPoints(QVector<QQuickEventPoint *> points);
+    bool grabPoints(const QVector<QQuickEventPoint *> &points);
     void moveTarget(QPointF pos);
 
     Q_DECLARE_PRIVATE(QQuickMultiPointHandler)
diff --git a/src/quick/items/qquickanimatedsprite.cpp b/src/quick/items/qquickanimatedsprite.cpp
index 18adb4e992..d22e77c8ad 100644
--- a/src/quick/items/qquickanimatedsprite.cpp
+++ b/src/quick/items/qquickanimatedsprite.cpp
@@ -532,7 +532,7 @@ void QQuickAnimatedSprite::setInterpolate(bool arg)
     }
 }
 
-void QQuickAnimatedSprite::setSource(QUrl arg)
+void QQuickAnimatedSprite::setSource(const QUrl &arg)
 {
     Q_D(QQuickAnimatedSprite);
 
diff --git a/src/quick/items/qquickanimatedsprite_p.h b/src/quick/items/qquickanimatedsprite_p.h
index ff59591c9f..d36f908c78 100644
--- a/src/quick/items/qquickanimatedsprite_p.h
+++ b/src/quick/items/qquickanimatedsprite_p.h
@@ -122,7 +122,7 @@ Q_SIGNALS:
     void runningChanged(bool arg);
     void interpolateChanged(bool arg);
 
-    void sourceChanged(QUrl arg);
+    void sourceChanged(const QUrl &arg);
     void reverseChanged(bool arg);
     void frameSyncChanged(bool arg);
     void frameCountChanged(int arg);
@@ -148,7 +148,7 @@ public Q_SLOTS:
     void setRunning(bool arg);
     void setPaused(bool arg);
     void setInterpolate(bool arg);
-    void setSource(QUrl arg);
+    void setSource(const QUrl &arg);
     void setReverse(bool arg);
     void setFrameSync(bool arg);
     void setFrameCount(int arg);
diff --git a/src/quick/items/qquickopenglshadereffect.cpp b/src/quick/items/qquickopenglshadereffect.cpp
index 0fd7df8938..e217fdb5d0 100644
--- a/src/quick/items/qquickopenglshadereffect.cpp
+++ b/src/quick/items/qquickopenglshadereffect.cpp
@@ -189,8 +189,8 @@ class MappedSlotObject: public QtPrivate::QSlotObjectBase
 public:
     typedef std::function<void()> PropChangedFunc;
 
-    explicit MappedSlotObject(PropChangedFunc func)
-        : QSlotObjectBase(&impl), _signalIndex(-1), func(func)
+    explicit MappedSlotObject(PropChangedFunc f)
+        : QSlotObjectBase(&impl), _signalIndex(-1), func(std::move(f))
     { ref(); }
 
     void setSignalIndex(int idx) { _signalIndex = idx; }
diff --git a/src/quick/items/qquickstateoperations.cpp b/src/quick/items/qquickstateoperations.cpp
index fe1dfd349e..31d1c91649 100644
--- a/src/quick/items/qquickstateoperations.cpp
+++ b/src/quick/items/qquickstateoperations.cpp
@@ -200,7 +200,7 @@ QQmlScriptString QQuickParentChange::x() const
     return d->xString.value;
 }
 
-void QQuickParentChange::setX(QQmlScriptString x)
+void QQuickParentChange::setX(const QQmlScriptString &x)
 {
     Q_D(QQuickParentChange);
     d->xString = x;
@@ -218,7 +218,7 @@ QQmlScriptString QQuickParentChange::y() const
     return d->yString.value;
 }
 
-void QQuickParentChange::setY(QQmlScriptString y)
+void QQuickParentChange::setY(const QQmlScriptString &y)
 {
     Q_D(QQuickParentChange);
     d->yString = y;
@@ -236,7 +236,7 @@ QQmlScriptString QQuickParentChange::width() const
     return d->widthString.value;
 }
 
-void QQuickParentChange::setWidth(QQmlScriptString width)
+void QQuickParentChange::setWidth(const QQmlScriptString &width)
 {
     Q_D(QQuickParentChange);
     d->widthString = width;
@@ -254,7 +254,7 @@ QQmlScriptString QQuickParentChange::height() const
     return d->heightString.value;
 }
 
-void QQuickParentChange::setHeight(QQmlScriptString height)
+void QQuickParentChange::setHeight(const QQmlScriptString &height)
 {
     Q_D(QQuickParentChange);
     d->heightString = height;
@@ -272,7 +272,7 @@ QQmlScriptString QQuickParentChange::scale() const
     return d->scaleString.value;
 }
 
-void QQuickParentChange::setScale(QQmlScriptString scale)
+void QQuickParentChange::setScale(const QQmlScriptString &scale)
 {
     Q_D(QQuickParentChange);
     d->scaleString = scale;
@@ -290,7 +290,7 @@ QQmlScriptString QQuickParentChange::rotation() const
     return d->rotationString.value;
 }
 
-void QQuickParentChange::setRotation(QQmlScriptString rotation)
+void QQuickParentChange::setRotation(const QQmlScriptString &rotation)
 {
     Q_D(QQuickParentChange);
     d->rotationString = rotation;
diff --git a/src/quick/items/qquickstateoperations_p.h b/src/quick/items/qquickstateoperations_p.h
index e947b2213f..357366bc60 100644
--- a/src/quick/items/qquickstateoperations_p.h
+++ b/src/quick/items/qquickstateoperations_p.h
@@ -87,27 +87,27 @@ public:
     QQuickItem *originalParent() const;
 
     QQmlScriptString x() const;
-    void setX(QQmlScriptString x);
+    void setX(const QQmlScriptString &x);
     bool xIsSet() const;
 
     QQmlScriptString y() const;
-    void setY(QQmlScriptString y);
+    void setY(const QQmlScriptString &y);
     bool yIsSet() const;
 
     QQmlScriptString width() const;
-    void setWidth(QQmlScriptString width);
+    void setWidth(const QQmlScriptString &width);
     bool widthIsSet() const;
 
     QQmlScriptString height() const;
-    void setHeight(QQmlScriptString height);
+    void setHeight(const QQmlScriptString &height);
     bool heightIsSet() const;
 
     QQmlScriptString scale() const;
-    void setScale(QQmlScriptString scale);
+    void setScale(const QQmlScriptString &scale);
     bool scaleIsSet() const;
 
     QQmlScriptString rotation() const;
-    void setRotation(QQmlScriptString rotation);
+    void setRotation(const QQmlScriptString &rotation);
     bool rotationIsSet() const;
 
     ActionList actions() override;
diff --git a/src/quick/items/qquicktableview.cpp b/src/quick/items/qquicktableview.cpp
index 95fac30808..295c6898bc 100644
--- a/src/quick/items/qquicktableview.cpp
+++ b/src/quick/items/qquicktableview.cpp
@@ -2582,7 +2582,7 @@ QJSValue QQuickTableView::rowHeightProvider() const
     return d_func()->rowHeightProvider;
 }
 
-void QQuickTableView::setRowHeightProvider(QJSValue provider)
+void QQuickTableView::setRowHeightProvider(const QJSValue &provider)
 {
     Q_D(QQuickTableView);
     if (provider.strictlyEquals(d->rowHeightProvider))
@@ -2598,7 +2598,7 @@ QJSValue QQuickTableView::columnWidthProvider() const
     return d_func()->columnWidthProvider;
 }
 
-void QQuickTableView::setColumnWidthProvider(QJSValue provider)
+void QQuickTableView::setColumnWidthProvider(const QJSValue &provider)
 {
     Q_D(QQuickTableView);
     if (provider.strictlyEquals(d->columnWidthProvider))
diff --git a/src/quick/items/qquicktableview_p.h b/src/quick/items/qquicktableview_p.h
index 3b113efa4f..a5f727d7a4 100644
--- a/src/quick/items/qquicktableview_p.h
+++ b/src/quick/items/qquicktableview_p.h
@@ -95,10 +95,10 @@ public:
     void setColumnSpacing(qreal spacing);
 
     QJSValue rowHeightProvider() const;
-    void setRowHeightProvider(QJSValue provider);
+    void setRowHeightProvider(const QJSValue &provider);
 
     QJSValue columnWidthProvider() const;
-    void setColumnWidthProvider(QJSValue provider);
+    void setColumnWidthProvider(const QJSValue &provider);
 
     virtual QVariant model() const;
     virtual void setModel(const QVariant &newModel);
diff --git a/src/quick/items/qquicktextcontrol.cpp b/src/quick/items/qquicktextcontrol.cpp
index ab3b0c4605..127b3c3516 100644
--- a/src/quick/items/qquicktextcontrol.cpp
+++ b/src/quick/items/qquicktextcontrol.cpp
@@ -1397,7 +1397,7 @@ QVariant QQuickTextControl::inputMethodQuery(Qt::InputMethodQuery property) cons
     return inputMethodQuery(property, QVariant());
 }
 
-QVariant QQuickTextControl::inputMethodQuery(Qt::InputMethodQuery property, QVariant argument) const
+QVariant QQuickTextControl::inputMethodQuery(Qt::InputMethodQuery property, const QVariant &argument) const
 {
     Q_D(const QQuickTextControl);
     QTextBlock block = d->cursor.block();
diff --git a/src/quick/items/qquicktextcontrol_p.h b/src/quick/items/qquicktextcontrol_p.h
index 3c7d48f918..41b8ed7821 100644
--- a/src/quick/items/qquicktextcontrol_p.h
+++ b/src/quick/items/qquicktextcontrol_p.h
@@ -174,7 +174,7 @@ public:
 
 #if QT_CONFIG(im)
     virtual QVariant inputMethodQuery(Qt::InputMethodQuery property) const;
-    Q_INVOKABLE QVariant inputMethodQuery(Qt::InputMethodQuery query, QVariant argument) const;
+    Q_INVOKABLE QVariant inputMethodQuery(Qt::InputMethodQuery query, const QVariant &argument) const;
 #endif
 
     virtual QMimeData *createMimeDataFromSelection() const;
diff --git a/src/quick/items/qquicktextinput.cpp b/src/quick/items/qquicktextinput.cpp
index b1ad6a1c15..34105d8c81 100644
--- a/src/quick/items/qquicktextinput.cpp
+++ b/src/quick/items/qquicktextinput.cpp
@@ -1958,7 +1958,7 @@ QVariant QQuickTextInput::inputMethodQuery(Qt::InputMethodQuery property) const
     return inputMethodQuery(property, QVariant());
 }
 
-QVariant QQuickTextInput::inputMethodQuery(Qt::InputMethodQuery property, QVariant argument) const
+QVariant QQuickTextInput::inputMethodQuery(Qt::InputMethodQuery property, const QVariant &argument) const
 {
     Q_D(const QQuickTextInput);
     switch (property) {
diff --git a/src/quick/items/qquicktextinput_p.h b/src/quick/items/qquicktextinput_p.h
index 92f3aa62ce..c10b06d02a 100644
--- a/src/quick/items/qquicktextinput_p.h
+++ b/src/quick/items/qquicktextinput_p.h
@@ -268,7 +268,7 @@ public:
 
 #if QT_CONFIG(im)
     QVariant inputMethodQuery(Qt::InputMethodQuery property) const override;
-    Q_REVISION(4) Q_INVOKABLE QVariant inputMethodQuery(Qt::InputMethodQuery query, QVariant argument) const;
+    Q_REVISION(4) Q_INVOKABLE QVariant inputMethodQuery(Qt::InputMethodQuery query, const QVariant &argument) const;
 #endif
 
     QRectF boundingRect() const override;
diff --git a/src/quick/items/qquicktextnodeengine.cpp b/src/quick/items/qquicktextnodeengine.cpp
index 7af90f0f8e..f8ebf13a1d 100644
--- a/src/quick/items/qquicktextnodeengine.cpp
+++ b/src/quick/items/qquicktextnodeengine.cpp
@@ -638,7 +638,7 @@ void QQuickTextNodeEngine::addBorder(const QRectF &rect, qreal border,
                                      QTextFrameFormat::BorderStyle borderStyle,
                                      const QBrush &borderBrush)
 {
-    QColor color = borderBrush.color();
+    const QColor &color = borderBrush.color();
 
     // Currently we don't support other styles than solid
     Q_UNUSED(borderStyle);
diff --git a/src/quick/items/qquickwindow.cpp b/src/quick/items/qquickwindow.cpp
index 1b766de007..64d7232354 100644
--- a/src/quick/items/qquickwindow.cpp
+++ b/src/quick/items/qquickwindow.cpp
@@ -2768,7 +2768,7 @@ void QQuickWindowPrivate::deliverMatchingPointsToItem(QQuickItem *item, QQuickPo
         // If the touch was accepted (regardless by whom or in what form),
         // update accepted new points.
         bool isPressOrRelease = pointerEvent->isPressEvent() || pointerEvent->isReleaseEvent();
-        for (auto point: qAsConst(touchEvent->touchPoints())) {
+        for (const auto &point: qAsConst(touchEvent->touchPoints())) {
             if (auto pointerEventPoint = ptEvent->pointById(point.id())) {
                 pointerEventPoint->setAccepted();
                 if (isPressOrRelease)
@@ -2778,7 +2778,7 @@ void QQuickWindowPrivate::deliverMatchingPointsToItem(QQuickItem *item, QQuickPo
     } else {
         // But if the event was not accepted then we know this item
         // will not be interested in further updates for those touchpoint IDs either.
-        for (auto point: qAsConst(touchEvent->touchPoints())) {
+        for (const auto &point: qAsConst(touchEvent->touchPoints())) {
             if (point.state() == Qt::TouchPointPressed) {
                 if (auto *tp = ptEvent->pointById(point.id())) {
                     if (tp->exclusiveGrabber() == item) {
@@ -3019,7 +3019,7 @@ bool QQuickWindowPrivate::sendFilteredPointerEventImpl(QQuickPointerEvent *event
                     if (filteringParent->childMouseEventFilter(receiver, filteringParentTouchEvent.data())) {
                         qCDebug(DBG_TOUCH) << "touch event intercepted by childMouseEventFilter of " << filteringParent;
                         skipDelivery.append(filteringParent);
-                        for (auto point: qAsConst(filteringParentTouchEvent->touchPoints())) {
+                        for (const auto &point: qAsConst(filteringParentTouchEvent->touchPoints())) {
                             QQuickEventPoint *pt = event->pointById(point.id());
                             pt->setAccepted();
                             pt->setGrabberItem(filteringParent);
diff --git a/src/quick/util/qquickanimation.cpp b/src/quick/util/qquickanimation.cpp
index 2043b50545..fe5b372da8 100644
--- a/src/quick/util/qquickanimation.cpp
+++ b/src/quick/util/qquickanimation.cpp
@@ -2636,7 +2636,7 @@ QQuickStateActions QQuickPropertyAnimation::createTransitionActions(QQuickStateA
             for (int j = 0; j < targets.count(); ++j) {
                 QQuickStateAction myAction;
                 QString errorMessage;
-                const QString propertyName = props.at(i);
+                const QString &propertyName = props.at(i);
                 myAction.property = d->createProperty(targets.at(j), propertyName, this, &errorMessage);
                 if (myAction.property.isValid()) {
                     if (usingDefaultProperties)
diff --git a/src/quick/util/qquickshortcut.cpp b/src/quick/util/qquickshortcut.cpp
index 730a14369e..5d227b4613 100644
--- a/src/quick/util/qquickshortcut.cpp
+++ b/src/quick/util/qquickshortcut.cpp
@@ -216,7 +216,7 @@ void QQuickShortcut::setSequences(const QVariantList &values)
 
     bool changed = !remainder.isEmpty();
     for (int i = 0; i < values.count(); ++i) {
-        QVariant value = values.at(i);
+        const QVariant &value = values.at(i);
         Shortcut& shortcut = m_shortcuts[i];
         if (value == shortcut.userValue)
             continue;
diff --git a/src/quick/util/qquickstategroup.cpp b/src/quick/util/qquickstategroup.cpp
index 0adae82dcc..46e7d62fc1 100644
--- a/src/quick/util/qquickstategroup.cpp
+++ b/src/quick/util/qquickstategroup.cpp
@@ -311,7 +311,7 @@ void QQuickStateGroup::componentComplete()
         if (!state->isNamed())
             state->setName(QLatin1String("anonymousState") + QString::number(++d->unnamedCount));
 
-        const QString stateName = state->name();
+        QString stateName = state->name();
         if (names.contains(stateName)) {
             qmlWarning(state->parent()) << "Found duplicate state name: " << stateName;
         } else {