diff --git a/autotests/unit/file/pendingfilequeuetest.cpp b/autotests/unit/file/pendingfilequeuetest.cpp
--- a/autotests/unit/file/pendingfilequeuetest.cpp
+++ b/autotests/unit/file/pendingfilequeuetest.cpp
@@ -61,7 +61,7 @@
     // The signal should be emitted immediately
     QVERIFY(spy.wait());
     QCOMPARE(spy.count(), 1);
-    QCOMPARE(spy.takeFirst().first().toString(), myUrl);
+    QCOMPARE(spy.takeFirst().constFirst().toString(), myUrl);
 
     // Enqueue the url again. This time it should wait for should wait for the
     // minimumTimeout
@@ -72,7 +72,7 @@
 
     QVERIFY(spy.wait(2000));
     QCOMPARE(spy.count(), 1);
-    QCOMPARE(spy.takeFirst().first().toString(), myUrl);
+    QCOMPARE(spy.takeFirst().constFirst().toString(), myUrl);
 }
 
 void PendingFileQueueTest::testRequeue()
@@ -93,7 +93,7 @@
     // The signal should be emitted immediately
     QTest::qWait(20);
     QCOMPARE(spy.count(), 1);
-    QCOMPARE(spy.takeFirst().first().toString(), myUrl);
+    QCOMPARE(spy.takeFirst().constFirst().toString(), myUrl);
 
     // Send many events
     queue.enqueue(file);
@@ -108,7 +108,7 @@
 
     QVERIFY(spy.wait(2500));
     QCOMPARE(spy.count(), 1);
-    QCOMPARE(spy.takeFirst().first().toString(), myUrl);
+    QCOMPARE(spy.takeFirst().constFirst().toString(), myUrl);
 }
 
 QTEST_GUILESS_MAIN(PendingFileQueueTest)
diff --git a/src/engine/transaction.cpp b/src/engine/transaction.cpp
--- a/src/engine/transaction.cpp
+++ b/src/engine/transaction.cpp
@@ -314,15 +314,17 @@
     vec.reserve(query.subQueries().size());
 
     if (query.op() == EngineQuery::Phrase) {
-        for (const EngineQuery& q : query.subQueries()) {
+        const auto subQueries = query.subQueries();
+        for (const EngineQuery& q : subQueries) {
             Q_ASSERT_X(q.leaf(), "Transaction::toPostingIterator", "Phrase queries must contain leaf queries");
             vec << positionDb.iter(q.term());
         }
 
         return new PhraseAndIterator(vec);
     }
 
-    for (const EngineQuery& q : query.subQueries()) {
+    const auto subQueries = query.subQueries();
+    for (const EngineQuery& q : subQueries) {
         vec << postingIterator(q);
     }
 
@@ -472,7 +474,7 @@
     out << "Total Document IDs: " << allIds.size() << endl;
 
     int count = 0;
-    for (quint64 id: allIds) {
+    for (quint64 id: qAsConst(allIds)) {
         QByteArray url = docUrlDb.get(id);
         if (url.isEmpty()) {
             auto terms = documentTermsDB.get(id);
@@ -491,7 +493,7 @@
 
             out << "Missing filePath for " << id << endl;
             out << "\tPostingDB Terms: ";
-            for (const QByteArray& term : newTerms) {
+            for (const QByteArray& term : qAsConst(newTerms)) {
                 out << term << " ";
             }
             out << endl;
@@ -545,12 +547,12 @@
 
     QTextStream out(stdout);
     out << "PostingDB check .." << endl;
-    for (quint64 id : allIds) {
+    for (quint64 id : qAsConst(allIds)) {
         QVector<QByteArray> terms = documentTermsDB.get(id);
         terms += documentXattrTermsDB.get(id);
         terms += documentFileNameTermsDB.get(id);
 
-        for (const QByteArray& term : terms) {
+        for (const QByteArray& term : qAsConst(terms)) {
             PostingList plist = postingDb.get(term);
             if (!plist.contains(id)) {
                 out << id << " is missing term " << term << endl;
diff --git a/src/file/fileindexerconfig.cpp b/src/file/fileindexerconfig.cpp
--- a/src/file/fileindexerconfig.cpp
+++ b/src/file/fileindexerconfig.cpp
@@ -323,7 +323,8 @@
 
     // Add all removable media and network shares as ignored unless they have
     // been explicitly added in the include list
-    for (const auto& device: m_devices->allMedia()) {
+    const auto allMedia = m_devices->allMedia();
+    for (const auto& device: allMedia) {
         const QString mountPath = device.mountPath();
         if (!device.isUsable() && !mountPath.isEmpty()) {
             if (!includeFoldersPlain.contains(mountPath)) {
diff --git a/src/file/fileindexscheduler.cpp b/src/file/fileindexscheduler.cpp
--- a/src/file/fileindexscheduler.cpp
+++ b/src/file/fileindexscheduler.cpp
@@ -172,7 +172,7 @@
         m_contentIndexer->quit();
         //TODO: Maybe we can add a special state for suspended due to being on battery.
         m_indexerState = Idle;
-        stateChanged(m_indexerState);
+        Q_EMIT stateChanged(m_indexerState);
     } else if (!isOnBattery) {
         scheduleIndexing();
     }
diff --git a/src/file/firstrunindexer.cpp b/src/file/firstrunindexer.cpp
--- a/src/file/firstrunindexer.cpp
+++ b/src/file/firstrunindexer.cpp
@@ -49,7 +49,7 @@
 
     QMimeDatabase mimeDb;
 
-    for (const QString& folder : m_folders) {
+    for (const QString& folder : qAsConst(m_folders)) {
         Transaction tr(m_db, Transaction::ReadWrite);
 
         FilteredDirIterator it(m_config, folder);
diff --git a/src/file/indexcleaner.cpp b/src/file/indexcleaner.cpp
--- a/src/file/indexcleaner.cpp
+++ b/src/file/indexcleaner.cpp
@@ -71,7 +71,8 @@
         return false;
     };
 
-    for (const QString& folder : m_config->includeFolders()) {
+    const auto includeFolders = m_config->includeFolders();
+    for (const QString& folder : includeFolders) {
         quint64 id = filePathToId(QFile::encodeName(folder));
         tr.removeRecursively(id, shouldDelete);
     }
diff --git a/src/file/modifiedfileindexer.cpp b/src/file/modifiedfileindexer.cpp
--- a/src/file/modifiedfileindexer.cpp
+++ b/src/file/modifiedfileindexer.cpp
@@ -48,7 +48,7 @@
 
     Transaction tr(m_db, Transaction::ReadWrite);
 
-    for (const QString& filePath : m_files) {
+    for (const QString& filePath : qAsConst(m_files)) {
         Q_ASSERT(!filePath.endsWith('/'));
 
         QString fileName = filePath.mid(filePath.lastIndexOf('/') + 1);
diff --git a/src/file/newfileindexer.cpp b/src/file/newfileindexer.cpp
--- a/src/file/newfileindexer.cpp
+++ b/src/file/newfileindexer.cpp
@@ -44,7 +44,7 @@
 
     Transaction tr(m_db, Transaction::ReadWrite);
 
-    for (const QString& filePath : m_files) {
+    for (const QString& filePath : qAsConst(m_files)) {
         Q_ASSERT(!filePath.endsWith('/'));
 
         QString fileName = filePath.mid(filePath.lastIndexOf('/') + 1);
diff --git a/src/file/xattrindexer.cpp b/src/file/xattrindexer.cpp
--- a/src/file/xattrindexer.cpp
+++ b/src/file/xattrindexer.cpp
@@ -44,7 +44,7 @@
 
     Transaction tr(m_db, Transaction::ReadWrite);
 
-    for (const QString& filePath : m_files) {
+    for (const QString& filePath : qAsConst(m_files)) {
         Q_ASSERT(!filePath.endsWith('/'));
 
         QString fileName = filePath.mid(filePath.lastIndexOf('/') + 1);
diff --git a/src/kioslaves/kded/baloosearchmodule.cpp b/src/kioslaves/kded/baloosearchmodule.cpp
--- a/src/kioslaves/kded/baloosearchmodule.cpp
+++ b/src/kioslaves/kded/baloosearchmodule.cpp
@@ -86,7 +86,7 @@
 void SearchModule::slotBalooFileDbChanged()
 {
     qDebug() << m_searchUrls;
-    for (const QUrl& dirUrl : m_searchUrls) {
+    for (const QUrl& dirUrl : qAsConst(m_searchUrls)) {
         org::kde::KDirNotify::emitFilesAdded(dirUrl);
     }
 }
diff --git a/src/lib/query.cpp b/src/lib/query.cpp
--- a/src/lib/query.cpp
+++ b/src/lib/query.cpp
@@ -185,7 +185,7 @@
 {
     Term term(d->m_term);
     if (!d->m_types.isEmpty()) {
-        for (const QString& type : d->m_types) {
+        for (const QString& type : qAsConst(d->m_types)) {
             term = term && Term(QStringLiteral("type"), type);
         }
     }
diff --git a/src/lib/searchstore.cpp b/src/lib/searchstore.cpp
--- a/src/lib/searchstore.cpp
+++ b/src/lib/searchstore.cpp
@@ -160,11 +160,11 @@
     Q_ASSERT(tr);
 
     if (term.operation() == Term::And || term.operation() == Term::Or) {
-        QList<Term> subTerms = term.subTerms();
+        const QList<Term> subTerms = term.subTerms();
         QVector<PostingIterator*> vec;
         vec.reserve(subTerms.size());
 
-        for (const Term& t : term.subTerms()) {
+        for (const Term& t : subTerms) {
             vec << constructQuery(tr, t);
         }
 
diff --git a/src/lib/taglistjob.cpp b/src/lib/taglistjob.cpp
--- a/src/lib/taglistjob.cpp
+++ b/src/lib/taglistjob.cpp
@@ -59,7 +59,7 @@
         tagList = tr.fetchTermsStartingWith("TAG-");
     }
     d->tags.reserve(tagList.size());
-    for (const QByteArray& ba : tagList) {
+    for (const QByteArray& ba : qAsConst(tagList)) {
         d->tags << QString::fromUtf8(ba.mid(4));
     }
 
diff --git a/src/lib/term.cpp b/src/lib/term.cpp
--- a/src/lib/term.cpp
+++ b/src/lib/term.cpp
@@ -459,7 +459,8 @@
     }
     else {
         d << "[" << operationToString(t.operation()).toUtf8().constData();
-        for (const Term& term : t.subTerms()) {
+        const auto subTerms = t.subTerms();
+        for (const Term& term : subTerms) {
             d << term;
         }
         d << "]";