diff --git a/autotests/kextracolumnsproxymodeltest.cpp b/autotests/kextracolumnsproxymodeltest.cpp
index 75fe9a6..04789cf 100644
--- a/autotests/kextracolumnsproxymodeltest.cpp
+++ b/autotests/kextracolumnsproxymodeltest.cpp
@@ -112,7 +112,7 @@ private Q_SLOTS:
         QCOMPARE(extractRowTexts(&mod, 0), QStringLiteral("ABCD"));
         QCOMPARE(extractRowTexts(&mod, 0, mod.index(0, 0)), QStringLiteral("mnop"));
         QCOMPARE(extractRowTexts(&mod, 1, mod.index(0, 0)), QStringLiteral("qrst"));
-        QCOMPARE(extractRowTexts(&mod, 0, mod.index(0, 0).child(1, 0)), QStringLiteral("uvww"));
+        QCOMPARE(extractRowTexts(&mod, 0, mod.index(1, 0, mod.index(0, 0))), QStringLiteral("uvww"));
         QCOMPARE(extractRowTexts(&mod, 1), QStringLiteral("EFGH"));
         QCOMPARE(extractRowTexts(&mod, 0, mod.index(1, 0)), QStringLiteral("xyz."));
         QCOMPARE(extractHorizontalHeaderTexts(&mod), QStringLiteral("H1H2H3H4"));
@@ -325,7 +325,7 @@ private Q_SLOTS:
         // And a selection
         QItemSelectionModel selection(&pm);
         selection.select(pm.index(0, 0), QItemSelectionModel::Select | QItemSelectionModel::Rows);
-        const QModelIndex grandChild = pm.index(0, 0).child(1, 0).child(0, 0);
+        const QModelIndex grandChild = pm.index(0, 0, pm.index(1, 0, pm.index(0, 0)));
         QCOMPARE(grandChild.data().toString(), QStringLiteral("u"));
         selection.select(grandChild, QItemSelectionModel::Select | QItemSelectionModel::Rows);
         const QModelIndexList lst = selection.selectedIndexes();
diff --git a/autotests/proxymodeltestsuite/dynamictreemodel.cpp b/autotests/proxymodeltestsuite/dynamictreemodel.cpp
index d727607..5159cd5 100644
--- a/autotests/proxymodeltestsuite/dynamictreemodel.cpp
+++ b/autotests/proxymodeltestsuite/dynamictreemodel.cpp
@@ -433,10 +433,9 @@ void ModelInsertCommand::interpret(const QString &treeString)
 {
     m_treeString = treeString;
 
-    QList<int> depths = getDepths(m_treeString);
+    const QList<int> depths = getDepths(m_treeString);
 
-    int size = 0;
-    qCount(depths, 0, size);
+    const int size = std::count(depths.begin(), depths.end(), 0);
     Q_ASSERT(size != 0);
 
     m_endRow = m_startRow + size - 1;
@@ -480,10 +479,8 @@ void ModelInsertCommand::doCommand()
     QModelIndex parent = findIndex(m_rowNumbers);
 
     if (!m_treeString.isEmpty()) {
-        QList<int> depths = getDepths(m_treeString);
-
-        int size = 0;
-        qCount(depths, 0, size);
+        const QList<int> depths = getDepths(m_treeString);
+        const int size = std::count(depths.begin(), depths.end(), 0);
         Q_ASSERT(size != 0);
         m_endRow = m_startRow + size - 1;
     }
@@ -512,7 +509,7 @@ void ModelInsertCommand::doCommand()
 
 void ModelInsertCommand::doInsertTree(const QModelIndex &fragmentParent)
 {
-    QList<int> depths = getDepths(m_treeString);
+    const QList<int> depths = getDepths(m_treeString);
 
     qint64 fragmentParentIdentifier = fragmentParent.internalId();
 
diff --git a/tests/proxymodeltestapp/kreparentingproxymodel.cpp b/tests/proxymodeltestapp/kreparentingproxymodel.cpp
index 9ada95e..ee62bcd 100644
--- a/tests/proxymodeltestapp/kreparentingproxymodel.cpp
+++ b/tests/proxymodeltestapp/kreparentingproxymodel.cpp
@@ -220,7 +220,7 @@ QModelIndex KReparentingProxyModelPrivate::getLastDescendant(const QModelIndex &
     QModelIndex proxyIndex = q->mapFromSource(index);
 
     while (q->hasChildren(proxyIndex)) {
-        proxyIndex = proxyIndex.child(q->rowCount(proxyIndex), proxyIndex.column());
+        proxyIndex = q->index(q->rowCount(proxyIndex), proxyIndex.column(), proxyIndex);
         if (!proxyIndex.isValid()) {
             break;
         }
@@ -308,7 +308,7 @@ QHash<QModelIndex, QModelIndexList> KReparentingProxyModelPrivate::recreateMappi
             break;
         }
 
-        const QVector<QModelIndex>::iterator ancestorIt = qLowerBound(ancestors.begin(), ancestors.end(), nextIndex, LessThan(q));
+        const QVector<QModelIndex>::iterator ancestorIt = std::lower_bound(ancestors.begin(), ancestors.end(), nextIndex, LessThan(q));
 
         ancestors.erase(ancestorIt, ancestors.end());