diff --git a/src/Gui/Command.cpp b/src/Gui/Command.cpp
index 0a400c6690..fb4820fc6b 100644
--- a/src/Gui/Command.cpp
+++ b/src/Gui/Command.cpp
@@ -498,7 +498,8 @@ void Command::testActive(void)
     Gui::ActionGroup* pcAction = qobject_cast<Gui::ActionGroup*>(_pcAction);
     if(pcAction) {
         Gui::CommandManager &rcCmdMgr = Gui::Application::Instance->commandManager();
-        for(auto action : pcAction->actions()) {
+        const auto actions = pcAction->actions();
+        for(auto action : actions) {
             auto name = action->property("CommandName").toByteArray();
             if(!name.size())
                 continue;
diff --git a/src/Gui/CommandLink.cpp b/src/Gui/CommandLink.cpp
index 56f597e0b3..824389343e 100644
--- a/src/Gui/CommandLink.cpp
+++ b/src/Gui/CommandLink.cpp
@@ -755,7 +755,8 @@ void StdCmdLinkSelectLinked::activated(int)
             doc->setActiveView(vp);
         }
     } else {
-        for(auto tree : getMainWindow()->findChildren<TreeWidget*>())
+        const auto trees = getMainWindow()->findChildren<TreeWidget*>();
+        for(auto tree : trees)
             tree->selectLinkedObject(linked);
     }
     Selection().selStackPush();
@@ -790,7 +791,8 @@ void StdCmdLinkSelectLinkedFinal::activated(int) {
     }
     Selection().selStackPush();
     Selection().clearCompleteSelection();
-    for(auto tree : getMainWindow()->findChildren<TreeWidget*>())
+    const auto trees = getMainWindow()->findChildren<TreeWidget*>();
+    for(auto tree : trees)
         tree->selectLinkedObject(linked);
     Selection().selStackPush();
 }
@@ -825,7 +827,8 @@ void StdCmdLinkSelectAllLinks::activated(int)
         return;
     Selection().selStackPush();
     Selection().clearCompleteSelection();
-    for(auto tree : getMainWindow()->findChildren<TreeWidget*>())
+    const auto trees = getMainWindow()->findChildren<TreeWidget*>();
+    for(auto tree : trees)
         tree->selectAllLinks(sels[0].pObject);
     Selection().selStackPush();
 }
diff --git a/src/Gui/CommandPyImp.cpp b/src/Gui/CommandPyImp.cpp
index 99064c72b0..6982168317 100644
--- a/src/Gui/CommandPyImp.cpp
+++ b/src/Gui/CommandPyImp.cpp
@@ -309,7 +309,8 @@ PyObject* CommandPy::getAction(PyObject *args)
 
         Py::List list;
         if (group) {
-            for (auto a : group->actions())
+            const auto actions = group->actions();
+            for (auto a : actions)
                 list.append(wrap.fromQObject(a));
         }
         else if (action) {
diff --git a/src/Gui/CommandView.cpp b/src/Gui/CommandView.cpp
index a86e805432..554f76add6 100644
--- a/src/Gui/CommandView.cpp
+++ b/src/Gui/CommandView.cpp
@@ -3013,7 +3013,8 @@ void StdCmdTreeSelectAllInstances::activated(int iMsg)
         return;
     Selection().selStackPush();
     Selection().clearCompleteSelection();
-    for(auto tree : getMainWindow()->findChildren<TreeWidget*>())
+    const auto trees = getMainWindow()->findChildren<TreeWidget*>();
+    for(auto tree : trees)
         tree->selectAllInstances(*vpd);
     Selection().selStackPush();
 }
@@ -3521,7 +3522,8 @@ StdTreeDrag::StdTreeDrag()
 void StdTreeDrag::activated(int)
 {
     if(Gui::Selection().hasSelection()) {
-        for(auto tree : getMainWindow()->findChildren<TreeWidget*>()) {
+        const auto trees = getMainWindow()->findChildren<TreeWidget*>();
+        for(auto tree : trees) {
             if(tree->isVisible()) {
                 tree->startDragging();
                 break;
diff --git a/src/Gui/DlgObjectSelection.cpp b/src/Gui/DlgObjectSelection.cpp
index efe75080c1..17f6b485ef 100644
--- a/src/Gui/DlgObjectSelection.cpp
+++ b/src/Gui/DlgObjectSelection.cpp
@@ -365,7 +365,8 @@ void DlgObjectSelection::onDepItemChanged(QTreeWidgetItem * depItem, int column)
     QSignalBlocker blocker3(ui->treeWidget);
     auto state = depItem->checkState(0);
     if (depItem->isSelected()) {
-        for (auto item : depItem->treeWidget()->selectedItems()) {
+        const auto items = depItem->treeWidget()->selectedItems();
+        for (auto item : items) {
             auto objT = qvariant_cast<App::SubObjectT>(item->data(0, Qt::UserRole));
             auto it = itemMap.find(objT);
             if (it == itemMap.end())
@@ -437,7 +438,8 @@ void DlgObjectSelection::onObjItemChanged(QTreeWidgetItem * objItem, int column)
         onItemSelectionChanged();
     }
     else {
-        for (auto item : ui->treeWidget->selectedItems()) {
+        const auto items = ui->treeWidget->selectedItems();
+        for (auto item : items) {
             setCheckState(item, state);
             itemChanged[qvariant_cast<App::SubObjectT>(item->data(0, Qt::UserRole))] = state;
         }
@@ -552,7 +554,8 @@ void DlgObjectSelection::onItemSelectionChanged() {
     inMap.clear();
 
     std::vector<App::DocumentObject *> sels;
-    for (auto item : ui->treeWidget->selectedItems()) {
+    const auto items = ui->treeWidget->selectedItems();
+    for (auto item : items) {
         if (item == allItem) {
             sels.clear();
             break;
diff --git a/src/Gui/DlgParameterImp.cpp b/src/Gui/DlgParameterImp.cpp
index 543ad7376a..147b2915a5 100644
--- a/src/Gui/DlgParameterImp.cpp
+++ b/src/Gui/DlgParameterImp.cpp
@@ -145,7 +145,7 @@ void DlgParameterImp::on_findGroupLE_textChanged(const QString &SearchStr)
 
     // at first reset all items to the default font and expand state
     if (foundList.size() > 0) {
-        for (QTreeWidgetItem* item : foundList) {
+        for (QTreeWidgetItem* item : qAsConst(foundList)) {
             item->setFont(0, defaultFont);
             item->setForeground(0, defaultColor);
             ExpandItem = item;
@@ -176,7 +176,7 @@ void DlgParameterImp::on_findGroupLE_textChanged(const QString &SearchStr)
         // reset background style sheet
         if (!ui->findGroupLE->styleSheet().isEmpty())
             ui->findGroupLE->setStyleSheet(QString());
-        for (QTreeWidgetItem* item : foundList) {
+        for (QTreeWidgetItem* item : qAsConst(foundList)) {
             item->setFont(0, boldFont);
             item->setForeground(0, Qt::red);
             // expand its parent to see the item
diff --git a/src/Gui/DlgPropertyLink.cpp b/src/Gui/DlgPropertyLink.cpp
index 5ee99da6b2..ded629e71b 100644
--- a/src/Gui/DlgPropertyLink.cpp
+++ b/src/Gui/DlgPropertyLink.cpp
@@ -161,9 +161,9 @@ QString DlgPropertyLink::formatObject(App::Document *ownerDoc, App::DocumentObje
                                                  QString::fromUtf8(sobj->Label.getValue()));
 }
 
-static inline bool isLinkSub(QList<App::SubObjectT> links)
+static inline bool isLinkSub(const QList<App::SubObjectT>& links)
 {
-    for(auto &link : links) {
+    for(const auto &link : links) {
         if(&link == &links.front())
             continue;
         if(link.getDocumentName() != links.front().getDocumentName()
@@ -353,7 +353,7 @@ void DlgPropertyLink::init(const App::DocumentObjectT &prop, bool tryFilter) {
     // For link list type property, try to auto filter type
     if(tryFilter && isLinkList) {
         Base::Type objType;
-        for(const auto& link : oldLinks) {
+        for(const auto& link : qAsConst(oldLinks)) {
             auto obj = link.getSubObject();
             if(!obj)
                 continue;
@@ -534,7 +534,8 @@ void DlgPropertyLink::onItemSelectionChanged()
     // Enforce single parent
     if(singleParent && currentObj && currentObj!=obj) {
         ui->treeWidget->blockSignals(true);
-        for(auto item : ui->treeWidget->selectedItems()) {
+        const auto items = ui->treeWidget->selectedItems();
+        for(auto item : items) {
             if(item != selections.back())
                 item->setSelected(false);
         }
@@ -707,7 +708,8 @@ DlgPropertyLink::getLinkFromItem(QTreeWidgetItem *item, bool needSubName) const
         return res;
     }
 
-    for(const QString &element : elements.split(QLatin1Char(','))) {
+    const auto split = elements.split(QLatin1Char(','));
+    for(const QString &element : split) {
         res.append(App::SubObjectT());
         res.last() = App::SubObjectT(sobj.getDocumentName().c_str(),
                                      sobj.getObjectName().c_str(),
@@ -1052,7 +1054,8 @@ void DlgPropertyLink::on_checkObjectType_toggled(bool on)
 void DlgPropertyLink::on_typeTree_itemSelectionChanged() {
 
     selectedTypes.clear();
-    for(auto item : ui->typeTree->selectedItems())
+    const auto items = ui->typeTree->selectedItems();
+    for(auto item : items)
         selectedTypes.insert(item->data(0, Qt::UserRole).toByteArray());
 
     if(ui->checkObjectType->isChecked())
diff --git a/src/Gui/DlgSettingsCacheDirectory.cpp b/src/Gui/DlgSettingsCacheDirectory.cpp
index 295d5f7ba6..eda5e9f2cb 100644
--- a/src/Gui/DlgSettingsCacheDirectory.cpp
+++ b/src/Gui/DlgSettingsCacheDirectory.cpp
@@ -301,14 +301,16 @@ qint64 ApplicationCache::dirSize(QString dirPath) const
     QDir dir(dirPath);
 
     QDir::Filters fileFilters = QDir::Files;
-    for (QString filePath : dir.entryList(fileFilters)) {
+    const auto& files = dir.entryList(fileFilters);
+    for (const QString& filePath : files) {
         QFileInfo fi(dir, filePath);
         total += fi.size();
     }
 
     // traverse sub-directories recursively
     QDir::Filters dirFilters = QDir::Dirs | QDir::NoDotAndDotDot;
-    for (QString subDirPath : dir.entryList(dirFilters))
+    const auto& dirs = dir.entryList(dirFilters);
+    for (const QString& subDirPath : dirs)
         total += dirSize(dirPath + QDir::separator() + subDirPath);
     return total;
 }
diff --git a/src/Gui/DocumentRecovery.cpp b/src/Gui/DocumentRecovery.cpp
index 0305ddea48..978b62abdd 100644
--- a/src/Gui/DocumentRecovery.cpp
+++ b/src/Gui/DocumentRecovery.cpp
@@ -723,7 +723,7 @@ void DocumentRecoveryCleaner::subtractFiles(QStringList& files)
 void DocumentRecoveryCleaner::subtractDirs(QFileInfoList& dirs)
 {
     if (!ignoreDirs.isEmpty() && !dirs.isEmpty()) {
-        for (const auto& it : ignoreDirs) {
+        for (const auto& it : qAsConst(ignoreDirs)) {
             dirs.removeOne(it);
         }
     }
diff --git a/src/Gui/Language/Translator.cpp b/src/Gui/Language/Translator.cpp
index 935532511f..c30fb56661 100644
--- a/src/Gui/Language/Translator.cpp
+++ b/src/Gui/Language/Translator.cpp
@@ -213,7 +213,7 @@ TStringMap Translator::supportedLocales() const
 
     // List all .qm files
     for (const auto& domainMap : d->mapLanguageTopLevelDomain) {
-        for (const auto& directoryName : d->paths) {
+        for (const auto& directoryName : qAsConst(d->paths)) {
             QDir dir(directoryName);
             QString filter = QString::fromLatin1("*_%1.qm").arg(QString::fromStdString(domainMap.second));
             QStringList fileNames = dir.entryList(QStringList(filter), QDir::Files, QDir::Name);
diff --git a/src/Gui/PropertyView.cpp b/src/Gui/PropertyView.cpp
index 5426716f58..0106505e4a 100644
--- a/src/Gui/PropertyView.cpp
+++ b/src/Gui/PropertyView.cpp
@@ -161,7 +161,8 @@ bool PropertyView::showAll() {
 void PropertyView::setShowAll(bool enable) {
     if(_ShowAll != enable) {
         _ShowAll = enable;
-        for(auto view : getMainWindow()->findChildren<PropertyView*>()) {
+        const auto views = getMainWindow()->findChildren<PropertyView*>();
+        for(auto view : views) {
             if(view->isVisible()) {
                 view->propertyEditorData->buildUp();
                 view->propertyEditorView->buildUp();
diff --git a/src/Gui/TaskElementColors.cpp b/src/Gui/TaskElementColors.cpp
index 40a9007556..dfdd396d26 100644
--- a/src/Gui/TaskElementColors.cpp
+++ b/src/Gui/TaskElementColors.cpp
@@ -215,7 +215,8 @@ public:
     }
 
     void removeItems() {
-        for(auto item : ui->elementList->selectedItems()) {
+        const auto items = ui->elementList->selectedItems();
+        for(auto item : items) {
             std::string sub = qPrintable(item->data(Qt::UserRole+1).value<QString>());
             if(sub == hiddenSub)
                 hiddenSub.clear();
@@ -259,8 +260,8 @@ public:
                    editObj == msg.pObjectName &&
                    boost::starts_with(msg.pSubName,editSub))
                 {
-                    for(auto item : ui->elementList->findItems(
-                                QString::fromLatin1(msg.pSubName-editSub.size()), Qt::MatchExactly))
+                    const auto items = ui->elementList->findItems(QString::fromLatin1(msg.pSubName-editSub.size()), Qt::MatchExactly);
+                    for(auto item : items)
                         item->setSelected(msg.Type==SelectionChanges::AddSelection);
                 }
             }
@@ -285,7 +286,8 @@ public:
             }
             break;
         }
-        for(auto item : ui->elementList->selectedItems()) {
+        const auto items = ui->elementList->selectedItems();
+        for(auto item : items) {
             std::string name(qPrintable(item->data(Qt::UserRole+1).value<QString>()));
             if(ViewProvider::hasHiddenMarker(name.c_str()))
                 continue;
diff --git a/src/Gui/Tree.cpp b/src/Gui/Tree.cpp
index 1b97a19291..16a9fc1398 100644
--- a/src/Gui/Tree.cpp
+++ b/src/Gui/Tree.cpp
@@ -1158,7 +1158,8 @@ void TreeWidget::onMarkRecompute()
 
 void TreeWidget::onRecomputeObject() {
     std::vector<App::DocumentObject*> objs;
-    for (auto ti : selectedItems()) {
+    const auto items = selectedItems();
+    for (auto ti : items) {
         if (ti->type() == ObjectType) {
             DocumentObjectItem* objitem = static_cast<DocumentObjectItem*>(ti);
             objs.push_back(objitem->object()->getObject());
@@ -1224,8 +1225,10 @@ std::vector<TreeWidget::SelInfo> TreeWidget::getSelection(App::Document* doc)
     else
         tree->_updateStatus(false);
 
-    for (auto ti : tree->selectedItems()) {
-        if (ti->type() != ObjectType) continue;
+    const auto items = tree->selectedItems();
+    for (auto ti : items) {
+        if (ti->type() != ObjectType)
+            continue;
         auto item = static_cast<DocumentObjectItem*>(ti);
         auto vp = item->object();
         auto obj = vp->getObject();
@@ -2736,7 +2739,8 @@ void TreeWidget::expandSelectedItems(TreeItemMode mode)
     if (!isSelectionAttached())
         return;
 
-    for (auto item : selectedItems()) {
+    const auto items = selectedItems();
+    for (auto item : items) {
         switch (mode) {
         case TreeItemMode::ExpandPath: {
             QTreeWidgetItem* parentItem = item->parent();
diff --git a/src/Gui/ViewProviderLink.cpp b/src/Gui/ViewProviderLink.cpp
index 9950a04c96..f007503608 100644
--- a/src/Gui/ViewProviderLink.cpp
+++ b/src/Gui/ViewProviderLink.cpp
@@ -2582,7 +2582,8 @@ void ViewProviderLink::_setupContextMenu(
             || (ext->getLinkPlacementProperty() && !ext->getLinkPlacementProperty()->isReadOnly()))
     {
         bool found = false;
-        for(auto action : menu->actions()) {
+        const auto actions = menu->actions();
+        for(auto action : actions) {
             if(action->data().toInt() == ViewProvider::Transform) {
                 found = true;
                 break;
@@ -2598,7 +2599,8 @@ void ViewProviderLink::_setupContextMenu(
 
     if(ext->getColoredElementsProperty()) {
         bool found = false;
-        for(auto action : menu->actions()) {
+        const auto actions = menu->actions();
+        for(auto action : actions) {
             if(action->data().toInt() == ViewProvider::Color) {
                 action->setText(QObject::tr("Override colors..."));
                 found = true;
diff --git a/src/Gui/Widgets.cpp b/src/Gui/Widgets.cpp
index 7534ee1156..57ef33d64c 100644
--- a/src/Gui/Widgets.cpp
+++ b/src/Gui/Widgets.cpp
@@ -1671,7 +1671,8 @@ ButtonGroup::ButtonGroup(QObject *parent)
     connect(this, qOverload<QAbstractButton *>(&QButtonGroup::buttonClicked),
             [=](QAbstractButton *button) {
         if (exclusive()) {
-            for (auto btn : buttons()) {
+            const auto btns = buttons();
+            for (auto btn : btns) {
                 if (btn && btn != button && btn->isCheckable())
                     btn->setChecked(false);
             }
diff --git a/src/Gui/propertyeditor/PropertyEditor.cpp b/src/Gui/propertyeditor/PropertyEditor.cpp
index fb12f727dd..c7d9af522b 100644
--- a/src/Gui/propertyeditor/PropertyEditor.cpp
+++ b/src/Gui/propertyeditor/PropertyEditor.cpp
@@ -624,7 +624,8 @@ void PropertyEditor::contextMenuEvent(QContextMenuEvent *) {
     auto contextIndex = currentIndex();
 
     std::unordered_set<App::Property*> props;
-    for(auto index : selectedIndexes()) {
+    const auto indexes = selectedIndexes();
+    for(const auto& index : indexes) {
         auto item = static_cast<PropertyItem*>(index.internalPointer());
         if(item->isSeparator())
             continue;
diff --git a/src/Gui/propertyeditor/PropertyItemDelegate.cpp b/src/Gui/propertyeditor/PropertyItemDelegate.cpp
index 616c428e65..41539dbae2 100644
--- a/src/Gui/propertyeditor/PropertyItemDelegate.cpp
+++ b/src/Gui/propertyeditor/PropertyItemDelegate.cpp
@@ -193,7 +193,8 @@ QWidget * PropertyItemDelegate::createEditor (QWidget * parent, const QStyleOpti
     this->pressed = false;
 
     if (editor) {
-        for (auto w : editor->findChildren<QWidget*>()) {
+        const auto widgets = editor->findChildren<QWidget*>();
+        for (auto w : widgets) {
             if (qobject_cast<QAbstractButton*>(w)
                     || qobject_cast<QLabel*>(w))
             {