diff --git a/src/corelib/kernel/qmimedata.cpp b/src/corelib/kernel/qmimedata.cpp
index 6650d2f626..9a3ec434c5 100644
--- a/src/corelib/kernel/qmimedata.cpp
+++ b/src/corelib/kernel/qmimedata.cpp
@@ -341,13 +341,7 @@ QList<QUrl> QMimeData::urls() const
 void QMimeData::setUrls(const QList<QUrl> &urls)
 {
     Q_D(QMimeData);
-    QList<QVariant> list;
-    const int numUrls = urls.size();
-    list.reserve(numUrls);
-    for (int i = 0; i < numUrls; ++i)
-        list.append(urls.at(i));
-
-    d->setData(textUriListLiteral(), list);
+    d->setData(textUriListLiteral(), QList<QVariant>(urls.cbegin(), urls.cend()));
 }
 
 /*!
diff --git a/src/corelib/plugin/qlibrary_unix.cpp b/src/corelib/plugin/qlibrary_unix.cpp
index 4ca205bb7d..84f572a003 100644
--- a/src/corelib/plugin/qlibrary_unix.cpp
+++ b/src/corelib/plugin/qlibrary_unix.cpp
@@ -199,7 +199,7 @@ bool QLibraryPrivate::load_sys()
                 continue;
             if (loadHints & QLibrary::LoadArchiveMemberHint) {
                 attempt = name;
-                int lparen = attempt.indexOf(u'(');
+                qsizetype lparen = attempt.indexOf(u'(');
                 if (lparen == -1)
                     lparen = attempt.size();
                 attempt = path + prefixes.at(prefix) + attempt.insert(lparen, suffixes.at(suffix));
diff --git a/src/corelib/plugin/qpluginloader.cpp b/src/corelib/plugin/qpluginloader.cpp
index b8052d5596..c6341199c9 100644
--- a/src/corelib/plugin/qpluginloader.cpp
+++ b/src/corelib/plugin/qpluginloader.cpp
@@ -235,7 +235,7 @@ static QString locatePlugin(const QString& fileName)
     suffixes.prepend(QString());
 
     // Split up "subdir/filename"
-    const int slash = fileName.lastIndexOf(u'/');
+    const qsizetype slash = fileName.lastIndexOf(u'/');
     const auto baseName = QStringView{fileName}.mid(slash + 1);
     const auto basePath = isAbsolute ? QStringView() : QStringView{fileName}.left(slash + 1); // keep the '/'
 
diff --git a/src/corelib/serialization/qcborvalue.cpp b/src/corelib/serialization/qcborvalue.cpp
index 20ba0c14ca..c10f412ea9 100644
--- a/src/corelib/serialization/qcborvalue.cpp
+++ b/src/corelib/serialization/qcborvalue.cpp
@@ -973,7 +973,7 @@ QCborContainerPrivate *QCborContainerPrivate::grow(QCborContainerPrivate *d, qsi
     Q_ASSERT(index >= 0);
     d = detach(d, index + 1);
     Q_ASSERT(d);
-    int j = d->elements.size();
+    qsizetype j = d->elements.size();
     while (j++ < index)
         d->append(Undefined());
     return d;
diff --git a/src/corelib/serialization/qjsonparser.cpp b/src/corelib/serialization/qjsonparser.cpp
index dba603815f..8d86639833 100644
--- a/src/corelib/serialization/qjsonparser.cpp
+++ b/src/corelib/serialization/qjsonparser.cpp
@@ -839,7 +839,7 @@ static inline bool scanUtf8Char(const char *&json, const char *end, char32_t *re
     const auto *usrc = reinterpret_cast<const uchar *>(json);
     const auto *uend = reinterpret_cast<const uchar *>(end);
     const uchar b = *usrc++;
-    int res = QUtf8Functions::fromUtf8<QUtf8BaseTraits>(b, result, usrc, uend);
+    qsizetype res = QUtf8Functions::fromUtf8<QUtf8BaseTraits>(b, result, usrc, uend);
     if (res < 0)
         return false;
 
diff --git a/src/corelib/serialization/qjsonwriter.cpp b/src/corelib/serialization/qjsonwriter.cpp
index b0e6ef1d0c..56c751426d 100644
--- a/src/corelib/serialization/qjsonwriter.cpp
+++ b/src/corelib/serialization/qjsonwriter.cpp
@@ -35,7 +35,7 @@ static QByteArray escapedString(const QString &s)
     while (src != end) {
         if (cursor >= ba_end - 6) {
             // ensure we have enough space
-            int pos = cursor - (const uchar *)ba.constData();
+            qptrdiff pos = cursor - (const uchar *)ba.constData();
             ba.resize(ba.size()*2);
             cursor = (uchar *)ba.data() + pos;
             ba_end = (const uchar *)ba.constData() + ba.size();
diff --git a/src/corelib/text/qlocale.cpp b/src/corelib/text/qlocale.cpp
index 6923e35736..9467f7795c 100644
--- a/src/corelib/text/qlocale.cpp
+++ b/src/corelib/text/qlocale.cpp
@@ -3384,7 +3384,9 @@ QString QCalendarBackend::dateTimeToString(QStringView format, const QDateTime &
         }
 
         const QChar c = format.at(i);
-        qsizetype repeat = qt_repeatCount(format.mid(i));
+        qsizetype rep = qt_repeatCount(format.mid(i));
+        Q_ASSERT(rep < std::numeric_limits<int>::max());
+        int repeat = int(rep);
         bool used = false;
         if (formatDate) {
             switch (c.unicode()) {
diff --git a/src/corelib/thread/qfutureinterface.cpp b/src/corelib/thread/qfutureinterface.cpp
index 790963547c..7784ec0939 100644
--- a/src/corelib/thread/qfutureinterface.cpp
+++ b/src/corelib/thread/qfutureinterface.cpp
@@ -800,7 +800,7 @@ void QFutureInterfaceBasePrivate::connectOutputInterface(QFutureCallOutInterface
 void QFutureInterfaceBasePrivate::disconnectOutputInterface(QFutureCallOutInterface *interface)
 {
     QMutexLocker lock(&m_mutex);
-    const int index = outputConnections.indexOf(interface);
+    const qsizetype index = outputConnections.indexOf(interface);
     if (index == -1)
         return;
     outputConnections.removeAt(index);
diff --git a/src/gui/kernel/qguiapplication.cpp b/src/gui/kernel/qguiapplication.cpp
index 27bf04da74..7ca58854ac 100644
--- a/src/gui/kernel/qguiapplication.cpp
+++ b/src/gui/kernel/qguiapplication.cpp
@@ -259,7 +259,7 @@ struct QWindowGeometrySpecification
 static inline int nextGeometryToken(const QByteArray &a, int &pos, char *op)
 {
     *op = 0;
-    const int size = a.size();
+    const qsizetype size = a.size();
     if (pos >= size)
         return -1;
 
@@ -1311,7 +1311,7 @@ static void init_platform(const QString &pluginNamesWithArguments, const QString
     if (!platformArguments.isEmpty()) {
         if (QObject *nativeInterface = QGuiApplicationPrivate::platform_integration->nativeInterface()) {
             for (const QString &argument : std::as_const(platformArguments)) {
-                const int equalsPos = argument.indexOf(u'=');
+                const qsizetype equalsPos = argument.indexOf(u'=');
                 const QByteArray name =
                     equalsPos != -1 ? argument.left(equalsPos).toUtf8() : argument.toUtf8();
                 const QVariant value =
@@ -1331,7 +1331,7 @@ static void init_plugins(const QList<QByteArray> &pluginList)
 {
     for (int i = 0; i < pluginList.size(); ++i) {
         QByteArray pluginSpec = pluginList.at(i);
-        int colonPos = pluginSpec.indexOf(':');
+        qsizetype colonPos = pluginSpec.indexOf(':');
         QObject *plugin;
         if (colonPos < 0)
             plugin = QGenericPluginFactory::create(QLatin1StringView(pluginSpec), QString());
@@ -1598,7 +1598,7 @@ void Q_TRACE_INSTRUMENT(qtgui) QGuiApplicationPrivate::init()
             ++i;
             if (argv[i] && *argv[i]) {
                 session_id = QString::fromLatin1(argv[i]);
-                int p = session_id.indexOf(u'_');
+                qsizetype p = session_id.indexOf(u'_');
                 if (p >= 0) {
                     session_key = session_id.mid(p +1);
                     session_id = session_id.left(p);
diff --git a/src/gui/kernel/qhighdpiscaling.cpp b/src/gui/kernel/qhighdpiscaling.cpp
index 31626ec222..a0e1b48dcb 100644
--- a/src/gui/kernel/qhighdpiscaling.cpp
+++ b/src/gui/kernel/qhighdpiscaling.cpp
@@ -699,7 +699,7 @@ QVector<QHighDpiScaling::ScreenFactor> QHighDpiScaling::parseScreenScaleFactorsS
     // - a semicolon-separated name=factor list: "foo=1.5;bar=2;baz=3"
     const auto specs = screenScaleFactors.split(u';');
     for (const auto &spec : specs) {
-        const int equalsPos = spec.lastIndexOf(u'=');
+        const qsizetype equalsPos = spec.lastIndexOf(u'=');
         if (equalsPos == -1) {
             // screens in order
             bool ok;
diff --git a/src/gui/kernel/qinternalmimedata.cpp b/src/gui/kernel/qinternalmimedata.cpp
index 9fd7f89a0f..d33402703e 100644
--- a/src/gui/kernel/qinternalmimedata.cpp
+++ b/src/gui/kernel/qinternalmimedata.cpp
@@ -20,7 +20,7 @@ static QStringList imageMimeFormats(const QList<QByteArray> &imageFormats)
         formats.append("image/"_L1 + QLatin1StringView(format.toLower()));
 
     //put png at the front because it is best
-    int pngIndex = formats.indexOf("image/png"_L1);
+    const qsizetype pngIndex = formats.indexOf("image/png"_L1);
     if (pngIndex != -1 && pngIndex != 0)
         formats.move(pngIndex, 0);
 
diff --git a/src/gui/kernel/qkeysequence.cpp b/src/gui/kernel/qkeysequence.cpp
index cd7256a5fb..ffd19f8b2f 100644
--- a/src/gui/kernel/qkeysequence.cpp
+++ b/src/gui/kernel/qkeysequence.cpp
@@ -940,7 +940,7 @@ QKeySequence QKeySequence::mnemonic(const QString &text)
         return ret;
 
     bool found = false;
-    int p = 0;
+    qsizetype p = 0;
     while (p >= 0) {
         p = text.indexOf(u'&', p) + 1;
         if (p <= 0 || p >= (int)text.size())
@@ -993,7 +993,7 @@ int QKeySequence::assign(const QString &ks, QKeySequence::SequenceFormat format)
 {
     QString keyseq = ks;
     int n = 0;
-    int p = 0, diff = 0;
+    qsizetype p = 0, diff = 0;
 
     // Run through the whole string, but stop
     // if we have MaxKeyCount keys before the end.
@@ -1111,8 +1111,8 @@ int QKeySequencePrivate::decodeString(QString accel, QKeySequence::SequenceForma
         return Qt::Key_unknown;
 #endif
 
-    int i = 0;
-    int lastI = 0;
+    qsizetype i = 0;
+    qsizetype lastI = 0;
     while ((i = sl.indexOf(u'+', i + 1)) != -1) {
         const QStringView sub = QStringView{sl}.mid(lastI, i - lastI + 1);
         // If we get here the shortcuts contains at least one '+'. We break up
@@ -1146,7 +1146,7 @@ int QKeySequencePrivate::decodeString(QString accel, QKeySequence::SequenceForma
         lastI = i + 1;
     }
 
-    int p = accel.lastIndexOf(u'+', accel.size() - 2); // -2 so that Ctrl++ works
+    qsizetype p = accel.lastIndexOf(u'+', accel.size() - 2); // -2 so that Ctrl++ works
     QStringView accelRef(accel);
     if (p > 0)
         accelRef = accelRef.mid(p + 1);
diff --git a/src/gui/kernel/qpointingdevice.cpp b/src/gui/kernel/qpointingdevice.cpp
index f890fc1ca8..3857d454d8 100644
--- a/src/gui/kernel/qpointingdevice.cpp
+++ b/src/gui/kernel/qpointingdevice.cpp
@@ -564,7 +564,7 @@ bool QPointingDevicePrivate::addPassiveGrabber(const QPointerEvent *event, const
 
 bool QPointingDevicePrivate::setPassiveGrabberContext(QPointingDevicePrivate::EventPointData *epd, QObject *grabber, QObject *context)
 {
-    int i = epd->passiveGrabbers.indexOf(grabber);
+    qsizetype i = epd->passiveGrabbers.indexOf(grabber);
     if (i < 0)
         return false;
     if (epd->passiveGrabbersContext.size() <= i)
@@ -581,7 +581,7 @@ bool QPointingDevicePrivate::removePassiveGrabber(const QPointerEvent *event, co
         qWarning() << "point is not in activePoints" << point;
         return false;
     }
-    int i = persistentPoint->passiveGrabbers.indexOf(grabber);
+    qsizetype i = persistentPoint->passiveGrabbers.indexOf(grabber);
     if (i >= 0) {
         if (Q_UNLIKELY(lcPointerGrab().isDebugEnabled())) {
             qCDebug(lcPointerGrab) << name << "point" << point.id() << point.state()
@@ -644,7 +644,7 @@ void QPointingDevicePrivate::removeGrabber(QObject *grabber, bool cancel)
                                 cancel ? QPointingDevice::CancelGrabExclusive : QPointingDevice::UngrabExclusive,
                                 nullptr, epd.eventPoint);
         }
-        int pi = epd.passiveGrabbers.indexOf(grabber);
+        qsizetype pi = epd.passiveGrabbers.indexOf(grabber);
         if (pi >= 0) {
             qCDebug(lcPointerGrab) << name << "point" << epd.eventPoint.id() << epd.eventPoint.state()
                                    << ": removing passive grabber" << grabber;
diff --git a/src/gui/kernel/qwindow.cpp b/src/gui/kernel/qwindow.cpp
index 81a4469a9e..e83ed33a36 100644
--- a/src/gui/kernel/qwindow.cpp
+++ b/src/gui/kernel/qwindow.cpp
@@ -431,14 +431,14 @@ void QWindowPrivate::updateSiblingPosition(SiblingPosition position)
 
     QObjectList &siblings = q->parent()->d_ptr->children;
 
-    const int siblingCount = siblings.size() - 1;
+    const qsizetype siblingCount = siblings.size() - 1;
     if (siblingCount == 0)
         return;
 
-    const int currentPosition = siblings.indexOf(q);
+    const qsizetype currentPosition = siblings.indexOf(q);
     Q_ASSERT(currentPosition >= 0);
 
-    const int targetPosition = position == PositionTop ? siblingCount : 0;
+    const qsizetype targetPosition = position == PositionTop ? siblingCount : 0;
 
     if (currentPosition == targetPosition)
         return;
diff --git a/src/gui/kernel/qwindowsysteminterface.cpp b/src/gui/kernel/qwindowsysteminterface.cpp
index 714a859590..be2157c8b9 100644
--- a/src/gui/kernel/qwindowsysteminterface.cpp
+++ b/src/gui/kernel/qwindowsysteminterface.cpp
@@ -138,7 +138,7 @@ static bool handleWindowSystemEvent(Args ...args)
     return QWindowSystemHelper<Delivery>::template handleEvent<EventType>(args...);
 }
 
-int QWindowSystemInterfacePrivate::windowSystemEventsQueued()
+qsizetype QWindowSystemInterfacePrivate::windowSystemEventsQueued()
 {
     return windowSystemEventQueue.count();
 }
@@ -791,7 +791,7 @@ void QWindowSystemInterface::handleScreenRemoved(QPlatformScreen *platformScreen
 void QWindowSystemInterface::handlePrimaryScreenChanged(QPlatformScreen *newPrimary)
 {
     QScreen *newPrimaryScreen = newPrimary->screen();
-    int indexOfScreen = QGuiApplicationPrivate::screen_list.indexOf(newPrimaryScreen);
+    qsizetype indexOfScreen = QGuiApplicationPrivate::screen_list.indexOf(newPrimaryScreen);
     Q_ASSERT(indexOfScreen >= 0);
     if (indexOfScreen == 0)
         return;
@@ -1058,7 +1058,7 @@ Q_GUI_EXPORT QDebug operator<<(QDebug dbg, const QWindowSystemInterface::TouchPo
 */
 bool QWindowSystemInterface::flushWindowSystemEvents(QEventLoop::ProcessEventsFlags flags)
 {
-    const int count = QWindowSystemInterfacePrivate::windowSystemEventQueue.count();
+    const qsizetype count = QWindowSystemInterfacePrivate::windowSystemEventQueue.count();
     if (!count)
         return false;
     if (!QGuiApplication::instance()) {
diff --git a/src/gui/kernel/qwindowsysteminterface_p.h b/src/gui/kernel/qwindowsysteminterface_p.h
index 3569667325..b08abc0a95 100644
--- a/src/gui/kernel/qwindowsysteminterface_p.h
+++ b/src/gui/kernel/qwindowsysteminterface_p.h
@@ -473,7 +473,7 @@ public:
         }
         void append(WindowSystemEvent *e)
         { const QMutexLocker locker(&mutex); impl.append(e); }
-        int count() const
+        qsizetype count() const
         { const QMutexLocker locker(&mutex); return impl.size(); }
         WindowSystemEvent *peekAtFirstOfType(EventType t) const
         {
@@ -500,7 +500,7 @@ public:
 
     static WindowSystemEventList windowSystemEventQueue;
 
-    static int windowSystemEventsQueued();
+    static qsizetype windowSystemEventsQueued();
     static bool nonUserInputEventsQueued();
     static WindowSystemEvent *getWindowSystemEvent();
     static WindowSystemEvent *getNonUserInputWindowSystemEvent();
diff --git a/src/gui/opengl/platform/egl/qeglconvenience.cpp b/src/gui/opengl/platform/egl/qeglconvenience.cpp
index 5124e2e5dc..4af50d72f2 100644
--- a/src/gui/opengl/platform/egl/qeglconvenience.cpp
+++ b/src/gui/opengl/platform/egl/qeglconvenience.cpp
@@ -88,13 +88,12 @@ QList<EGLint> q_createConfigAttributesFromFormat(const QSurfaceFormat &format)
 
 bool q_reduceConfigAttributes(QList<EGLint> *configAttributes)
 {
-    int i = -1;
     // Reduce the complexity of a configuration request to ask for less
     // because the previous request did not result in success.  Returns
     // true if the complexity was reduced, or false if no further
     // reductions in complexity are possible.
 
-    i = configAttributes->indexOf(EGL_SWAP_BEHAVIOR);
+    qsizetype i = configAttributes->indexOf(EGL_SWAP_BEHAVIOR);
     if (i >= 0) {
         configAttributes->remove(i,2);
     }
@@ -258,7 +257,7 @@ EGLConfig QEglConfigChooser::chooseConfig()
 
         // Fetch all of the matching configurations and find the
         // first that matches the pixel format we wanted.
-        int i = configureAttributes.indexOf(EGL_RED_SIZE);
+        qsizetype i = configureAttributes.indexOf(EGL_RED_SIZE);
         m_confAttrRed = configureAttributes.at(i+1);
         i = configureAttributes.indexOf(EGL_GREEN_SIZE);
         m_confAttrGreen = configureAttributes.at(i+1);
@@ -268,7 +267,8 @@ EGLConfig QEglConfigChooser::chooseConfig()
         m_confAttrAlpha = i == -1 ? 0 : configureAttributes.at(i+1);
 
         QList<EGLConfig> configs(matching);
-        eglChooseConfig(display(), configureAttributes.constData(), configs.data(), configs.size(), &matching);
+        eglChooseConfig(display(), configureAttributes.constData(), configs.data(),
+                        EGLint(configs.size()), &matching);
         if (!cfg && matching > 0)
             cfg = configs.first();
 
diff --git a/src/gui/opengl/qopengl.cpp b/src/gui/opengl/qopengl.cpp
index 7c997103d5..587975085a 100644
--- a/src/gui/opengl/qopengl.cpp
+++ b/src/gui/opengl/qopengl.cpp
@@ -385,7 +385,8 @@ static bool readGpuFeatures(const QOpenGLConfig::Gpu &gpu,
     QJsonParseError error;
     const QJsonDocument document = QJsonDocument::fromJson(jsonAsciiData, &error);
     if (document.isNull()) {
-        const int lineNumber = 1 + jsonAsciiData.left(error.offset).count('\n');
+        const qsizetype lineNumber =
+                QByteArrayView(jsonAsciiData).left(error.offset).count('\n') + 1;
         QTextStream str(errorMessage);
         str << "Failed to parse data: \"" << error.errorString()
             << "\" at line " << lineNumber << " (offset: "