diff --git a/autotests/kwindowsystem_threadtest.cpp b/autotests/kwindowsystem_threadtest.cpp
--- a/autotests/kwindowsystem_threadtest.cpp
+++ b/autotests/kwindowsystem_threadtest.cpp
@@ -58,7 +58,7 @@
     {
         // simulate some activity in another thread gathering window information
         const QList<WId> windows = KWindowSystem::stackingOrder();
-        foreach (auto wid, windows) {
+        for (auto wid : windows) {
             KWindowInfo info(wid, NET::WMVisibleName);
             if (info.valid()) {
                 m_names << info.visibleName();
diff --git a/src/platforms/xcb/kwindoweffects.cpp b/src/platforms/xcb/kwindoweffects.cpp
--- a/src/platforms/xcb/kwindoweffects.cpp
+++ b/src/platforms/xcb/kwindoweffects.cpp
@@ -137,7 +137,7 @@
 QList<QSize> KWindowEffectsPrivateX11::windowSizes(const QList<WId> &ids)
 {
     QList<QSize> windowSizes;
-    Q_FOREACH (WId id, ids) {
+    for (WId id : ids) {
         if (id > 0) {
             KWindowInfo info(id, NET::WMGeometry | NET::WMFrameExtents);
             windowSizes.append(info.frameGeometry().size());
diff --git a/src/platforms/xcb/kwindowsystem.cpp b/src/platforms/xcb/kwindowsystem.cpp
--- a/src/platforms/xcb/kwindowsystem.cpp
+++ b/src/platforms/xcb/kwindowsystem.cpp
@@ -58,8 +58,9 @@
         static QList<QMetaObject::Connection> connections;
         auto dirtify = [&] {
             isDirty = true;
-            foreach (const QMetaObject::Connection &con, connections)
+            for (const QMetaObject::Connection &con : qAsConst(connections)) {
                 QObject::disconnect(con);
+            }
             connections.clear();
         };
 
diff --git a/src/platforms/xcb/netwm.cpp b/src/platforms/xcb/netwm.cpp
--- a/src/platforms/xcb/netwm.cpp
+++ b/src/platforms/xcb/netwm.cpp
@@ -1992,7 +1992,7 @@
         p->actions = NET::Actions();
 
         const QVector<xcb_atom_t> atoms = get_array_reply<xcb_atom_t>(p->conn, cookies[c++], XCB_ATOM_ATOM);
-        Q_FOREACH (const xcb_atom_t atom, atoms) {
+        for (const xcb_atom_t atom : atoms) {
             updateSupportedProperties(atom);
         }
     }
@@ -4045,7 +4045,7 @@
         fprintf(stderr, "NETWinInfo::update: updating window state (%ld)\n", states.count());
 #endif
 
-        Q_FOREACH (const xcb_atom_t state, states) {
+        for (const xcb_atom_t state : states) {
 #ifdef NETWMDEBUG
             const QByteArray ba = get_atom_name(p->conn, state);
             fprintf(stderr, "NETWinInfo::update:   adding window state %ld '%s'\n",
@@ -4182,7 +4182,7 @@
             p->has_net_support = true;
             int pos = 0;
 
-            Q_FOREACH (const xcb_atom_t type, types) {
+            for (const xcb_atom_t type : types) {
 #ifdef NETWMDEBUG
                 const QByteArray name = get_atom_name(p->conn, type);
                 fprintf(stderr,  "NETWinInfo::update:   examining window type %ld %s\n",
@@ -4413,7 +4413,7 @@
             fprintf(stderr, "NETWinInfo::update: updating allowed actions (%ld)\n", actions.count());
 #endif
 
-            Q_FOREACH (const xcb_atom_t action, actions) {
+            for (const xcb_atom_t action : actions) {
 #ifdef NETWMDEBUG
                 const QByteArray name = get_atom_name(p->conn, action);
                 fprintf(stderr,
diff --git a/src/pluginwrapper.cpp b/src/pluginwrapper.cpp
--- a/src/pluginwrapper.cpp
+++ b/src/pluginwrapper.cpp
@@ -37,12 +37,14 @@
 static QStringList pluginCandidates()
 {
     QStringList ret;
-    foreach (const QString &path, QCoreApplication::libraryPaths()) {
+    const auto paths = QCoreApplication::libraryPaths();
+    for (const QString &path : paths) {
         QDir pluginDir(path + QLatin1String("/kf5/org.kde.kwindowsystem.platforms"));
         if (!pluginDir.exists()) {
             continue;
         }
-        foreach (const QString &entry, pluginDir.entryList(QDir::Files | QDir::NoDotAndDotDot)) {
+        const auto entries = pluginDir.entryList(QDir::Files | QDir::NoDotAndDotDot);
+        for (const QString &entry : entries) {
             ret << pluginDir.absoluteFilePath(entry);
         }
     }
@@ -59,7 +61,8 @@
             platformName = flatpakPlatform;
         }
     }
-    foreach (const QString &candidate, pluginCandidates()) {
+    const auto candidates = pluginCandidates();
+    for (const QString &candidate : candidates) {
         if (!QLibrary::isLibrary(candidate)) {
             continue;
         }