Qt Designer: Fix Qt API usage

Replace:
   empty() by isEmpty()
   front()/back() by constFirst()/constLast(), preventing detaching

Streamline some code.

Task-number: QTBUG-79896
Change-Id: Ic3f8414db79a83a30b55369a9352f332b41aa621
Reviewed-by: Jarek Kobus <jaroslaw.kobus@qt.io>

1 files changed, 2 insertions, 2 deletions

diff --git a/src/designer/src/lib/shared/qdesigner_promotiondialog.cpp b/src/designer/src/lib/shared/qdesigner_promotiondialog.cpp
index 7058b0c81..1ec5cd9ae 100644
--- a/src/designer/src/lib/shared/qdesigner_promotiondialog.cpp
+++ b/src/designer/src/lib/shared/qdesigner_promotiondialog.cpp
@@ -290,7 +290,7 @@ namespace qdesigner_internal {
     const QStringList &QDesignerPromotionDialog::baseClassNames(const QDesignerPromotionInterface *promotion) {
         using WidgetDataBaseItemList = QList<QDesignerWidgetDataBaseItemInterface *>;
         static QStringList rc;
-        if (rc.empty()) {
+        if (rc.isEmpty()) {
             // Convert the item list into a string list.
             const WidgetDataBaseItemList dbItems =  promotion->promotionBaseClasses();
             const WidgetDataBaseItemList::const_iterator cend =  dbItems.constEnd();
@@ -351,7 +351,7 @@ namespace qdesigner_internal {
     QDesignerWidgetDataBaseItemInterface *QDesignerPromotionDialog::databaseItemAt(const QItemSelection &selected, unsigned &flags) const {
         flags = 0;
         const QModelIndexList indexes = selected.indexes();
-        if (indexes.empty())
+        if (indexes.isEmpty())
             return nullptr;
         const PromotionModel::ModelData data = m_model->modelData(indexes.constFirst());
         QDesignerWidgetDataBaseItemInterface *dbItem = data.promotedItem;