diff --git a/ext/libstrawberry-common/core/logging.cpp b/ext/libstrawberry-common/core/logging.cpp
index 380f3f426..85c321efa 100644
--- a/ext/libstrawberry-common/core/logging.cpp
+++ b/ext/libstrawberry-common/core/logging.cpp
@@ -165,7 +165,7 @@ static void MessageHandler(QtMsgType type, const QMessageLogContext&, const QStr
     d << line.toLocal8Bit().constData();
     if (d.buf_) {
       d.buf_->close();
-      fprintf(type == QtCriticalMsg || type == QtFatalMsg ? stderr : stdout, "%s\n", d.buf_->buffer().data());
+      fprintf(type == QtCriticalMsg || type == QtFatalMsg ? stderr : stdout, "%s\n", d.buf_->buffer().constData());
       fflush(type == QtCriticalMsg || type == QtFatalMsg ? stderr : stdout);
     }
   }
diff --git a/src/analyzer/analyzercontainer.cpp b/src/analyzer/analyzercontainer.cpp
index 364bb3386..6d1900586 100644
--- a/src/analyzer/analyzercontainer.cpp
+++ b/src/analyzer/analyzercontainer.cpp
@@ -149,7 +149,7 @@ void AnalyzerContainer::DisableAnalyzer() {
 
 void AnalyzerContainer::ChangeAnalyzer(const int id) {
 
-  QObject *instance = analyzer_types_[id]->newInstance(Q_ARG(QWidget*, this));
+  QObject *instance = analyzer_types_.at(id)->newInstance(Q_ARG(QWidget*, this));
 
   if (!instance) {
     qLog(Warning) << "Couldn't initialize a new" << analyzer_types_[id]->className();
@@ -200,22 +200,25 @@ void AnalyzerContainer::Load() {
     for (int i = 0; i < analyzer_types_.count(); ++i) {
       if (type == QString::fromLatin1(analyzer_types_[i]->className())) {
         ChangeAnalyzer(i);
-        actions_[i]->setChecked(true);
+        QAction *action = actions_.value(i);
+        action->setChecked(true);
         break;
       }
     }
     if (!current_analyzer_) {
       ChangeAnalyzer(0);
-      actions_[0]->setChecked(true);
+      QAction *action = actions_.value(0);
+      action->setChecked(true);
     }
   }
 
   // Framerate
-  QList<QAction*> actions = group_framerate_->actions();
+  const QList<QAction*> actions = group_framerate_->actions();
   for (int i = 0; i < framerate_list_.count(); ++i) {
-    if (current_framerate_ == framerate_list_[i]) {
+    if (current_framerate_ == framerate_list_.value(i)) {
       ChangeFramerate(current_framerate_);
-      actions[i]->setChecked(true);
+      QAction *action = actions[i];
+      action->setChecked(true);
       break;
     }
   }
diff --git a/src/analyzer/blockanalyzer.cpp b/src/analyzer/blockanalyzer.cpp
index d36ffebb5..90840ddee 100644
--- a/src/analyzer/blockanalyzer.cpp
+++ b/src/analyzer/blockanalyzer.cpp
@@ -167,11 +167,12 @@ void BlockAnalyzer::analyze(QPainter &p, const Scope &s, const bool new_frame) {
 
   for (int x = 0, y = 0; x < static_cast<int>(scope_.size()); ++x) {
     // determine y
-    for (y = 0; scope_[x] < yscale_[y]; ++y);
+    for (y = 0; scope_[x] < yscale_.at(y); ++y);
 
     // This is opposite to what you'd think, higher than y means the bar is lower than y (physically)
-    if (static_cast<double>(y) > store_[x]) {
-      y = static_cast<int>(store_[x] += step_);
+    if (static_cast<double>(y) > store_.value(x)) {
+      store_[x] += step_;
+      y = static_cast<int>(store_.value(x));
     }
     else {
       store_[x] = y;
@@ -179,18 +180,19 @@ void BlockAnalyzer::analyze(QPainter &p, const Scope &s, const bool new_frame) {
 
     // If y is lower than fade_pos_, then the bar has exceeded the height of the fadeout
     // if the fadeout is quite faded now, then display the new one
-    if (y <= fade_pos_[x] /*|| fade_intensity_[x] < kFadeSize / 3*/) {
+    if (y <= fade_pos_.at(x) /*|| fade_intensity_[x] < kFadeSize / 3*/) {
       fade_pos_[x] = y;
       fade_intensity_[x] = kFadeSize;
     }
 
-    if (fade_intensity_[x] > 0) {
-      const int offset = --fade_intensity_[x];
-      const int y2 = y_ + (fade_pos_[x] * (kHeight + 1));
+    if (fade_intensity_.at(x) > 0) {
+      --fade_intensity_[x];
+      const int offset = fade_intensity_.value(x);
+      const int y2 = y_ + (fade_pos_.value(x) * (kHeight + 1));
       canvas_painter.drawPixmap(x * (kWidth + 1), y2, fade_bars_[offset], 0, 0, kWidth, height() - y2);
     }
 
-    if (fade_intensity_[x] == 0) fade_pos_[x] = rows_;
+    if (fade_intensity_.at(x) == 0) fade_pos_[x] = rows_;
 
     // REMEMBER: y is a number from 0 to rows_, 0 means all blocks are glowing, rows_ means none are
     canvas_painter.drawPixmap(x * (kWidth + 1), y * (kHeight + 1) + y_, *bar(), 0, y * (kHeight + 1), bar()->width(), bar()->height());
diff --git a/src/collection/collectionfilterwidget.cpp b/src/collection/collectionfilterwidget.cpp
index e257374d3..5a795edb2 100644
--- a/src/collection/collectionfilterwidget.cpp
+++ b/src/collection/collectionfilterwidget.cpp
@@ -158,7 +158,7 @@ void CollectionFilterWidget::Init(CollectionModel *model, CollectionFilter *filt
 
   const QList<QAction*> actions = filter_max_ages_.keys();
   for (QAction *action : actions) {
-    int filter_max_age = filter_max_ages_[action];
+    const int filter_max_age = filter_max_ages_.value(action);
     QObject::connect(action, &QAction::triggered, this, [this, filter_max_age]() { model_->SetFilterMaxAge(filter_max_age); } );
   }
 
diff --git a/src/collection/collectionmodel.cpp b/src/collection/collectionmodel.cpp
index 8182685ab..0dd03de2a 100644
--- a/src/collection/collectionmodel.cpp
+++ b/src/collection/collectionmodel.cpp
@@ -514,7 +514,7 @@ void CollectionModel::AddReAddOrUpdateSongsInternal(const SongList &songs) {
       songs_added << new_song;
       continue;
     }
-    const Song &old_song = song_nodes_[new_song.id()]->metadata;
+    const Song old_song = song_nodes_.value(new_song.id())->metadata;
     bool container_key_changed = false;
     bool has_unique_album_identifier_1 = false;
     bool has_unique_album_identifier_2 = false;
@@ -606,7 +606,7 @@ void CollectionModel::UpdateSongsInternal(const SongList &songs) {
       qLog(Error) << "Song does not exist in model" << new_song.id() << new_song.PrettyTitleWithArtist();
       continue;
     }
-    CollectionItem *item = song_nodes_[new_song.id()];
+    CollectionItem *item = song_nodes_.value(new_song.id());
     const Song &old_song = item->metadata;
     const bool song_title_data_changed = IsSongTitleDataChanged(old_song, new_song);
     const bool art_changed = !old_song.IsArtEqual(new_song);
@@ -648,7 +648,7 @@ void CollectionModel::RemoveSongsInternal(const SongList &songs) {
   for (const Song &song : songs) {
 
     if (song_nodes_.contains(song.id())) {
-      CollectionItem *node = song_nodes_[song.id()];
+      CollectionItem *node = song_nodes_.value(song.id());
 
       if (node->parent != root_) parents << node->parent;
 
@@ -706,7 +706,7 @@ void CollectionModel::RemoveSongsInternal(const SongList &songs) {
     }
 
     // Remove the divider
-    int row = divider_nodes_[divider_key]->row;
+    const int row = divider_nodes_.value(divider_key)->row;
     beginRemoveRows(ItemToIndex(root_), row, row);
     root_->Delete(row);
     endRemoveRows();
diff --git a/src/collection/collectionview.cpp b/src/collection/collectionview.cpp
index 72c4288c7..a392cf3c7 100644
--- a/src/collection/collectionview.cpp
+++ b/src/collection/collectionview.cpp
@@ -611,7 +611,7 @@ void CollectionView::SearchForThis() {
       CollectionItem *item = app_->collection_model()->IndexToItem(index);
       const CollectionModel::GroupBy group_by = app_->collection_model()->GetGroupBy()[item->container_level];
       while (!item->children.isEmpty()) {
-        item = item->children.first();
+        item = item->children.constFirst();
       }
 
       switch (group_by) {
diff --git a/src/collection/collectionwatcher.cpp b/src/collection/collectionwatcher.cpp
index 46a50fdd4..9d5b17496 100644
--- a/src/collection/collectionwatcher.cpp
+++ b/src/collection/collectionwatcher.cpp
@@ -1131,7 +1131,7 @@ void CollectionWatcher::RescanPathsNow() {
     if (stop_or_abort_requested()) break;
     ScanTransaction transaction(this, dir, false, false, mark_songs_unavailable_);
 
-    const QStringList paths = rescan_queue_[dir];
+    const QStringList paths = rescan_queue_.value(dir);
 
     QMap<QString, quint64> subdir_files_count;
     for (const QString &path : paths) {
diff --git a/src/core/database.cpp b/src/core/database.cpp
index 040715543..1b36c7416 100644
--- a/src/core/database.cpp
+++ b/src/core/database.cpp
@@ -161,7 +161,7 @@ QSqlDatabase Database::Connect() {
   // Attach external databases
   QStringList keys = attached_databases_.keys();
   for (const QString &key : std::as_const(keys)) {
-    QString filename = attached_databases_[key].filename_;
+    QString filename = attached_databases_.value(key).filename_;
 
     if (!injected_database_name_.isNull()) filename = injected_database_name_;
 
@@ -182,7 +182,7 @@ QSqlDatabase Database::Connect() {
   // We might have to initialize the schema in some attached databases now, if they were deleted and don't match up with the main schema version.
   keys = attached_databases_.keys();
   for (const QString &key : std::as_const(keys)) {
-    if (attached_databases_[key].is_temporary_ && attached_databases_[key].schema_.isEmpty()) {
+    if (attached_databases_.value(key).is_temporary_ && attached_databases_.value(key).schema_.isEmpty()) {
       continue;
     }
     // Find out if there are any tables in this database
@@ -258,7 +258,7 @@ void Database::RecreateAttachedDb(const QString &database_name) {
     return;
   }
 
-  const QString filename = attached_databases_[database_name].filename_;
+  const QString filename = attached_databases_.value(database_name).filename_;
 
   QMutexLocker l(&mutex_);
   {
diff --git a/src/core/deletefiles.cpp b/src/core/deletefiles.cpp
index 739dfcecc..d8a0137f4 100644
--- a/src/core/deletefiles.cpp
+++ b/src/core/deletefiles.cpp
@@ -116,7 +116,7 @@ void DeleteFiles::ProcessSomeFiles() {
   for (; progress_ < n; ++progress_) {
     task_manager_->SetTaskProgress(task_id_, progress_, songs_.count());
 
-    const Song &song = songs_[progress_];
+    const Song song = songs_.value(progress_);
 
     MusicStorage::DeleteJob job;
     job.metadata_ = song;
diff --git a/src/core/mergedproxymodel.cpp b/src/core/mergedproxymodel.cpp
index c5455aba0..a2d898498 100644
--- a/src/core/mergedproxymodel.cpp
+++ b/src/core/mergedproxymodel.cpp
@@ -535,8 +535,8 @@ void MergedProxyModel::LayoutChanged() {
   for (QAbstractItemModel *model : models) {
     if (!old_merge_points_.contains(model)) continue;
 
-    const int old_row = old_merge_points_[model].row();
-    const int new_row = merge_points_[model].row();
+    const int old_row = old_merge_points_.value(model).row();
+    const int new_row = merge_points_.value(model).row();
 
     if (old_row != new_row) {
       beginResetModel();
diff --git a/src/core/player.cpp b/src/core/player.cpp
index 59059a07b..736d23d88 100644
--- a/src/core/player.cpp
+++ b/src/core/player.cpp
@@ -618,7 +618,8 @@ void Player::UnPause() {
       if (time >= 30) {  // Stream URL might be expired.
         qLog(Debug) << "Re-requesting stream URL for" << song.url();
         play_offset_nanosec_ = engine_->position_nanosec();
-        HandleLoadResult(url_handlers_[song.url().scheme()]->StartLoading(song.url()));
+        UrlHandler *url_handler = url_handlers_.value(song.url().scheme());
+        HandleLoadResult(url_handler->StartLoading(song.url()));
         return;
       }
     }
@@ -826,7 +827,8 @@ void Player::PlayAt(const int index, const bool pause, const quint64 offset_nano
     pause_ = pause;
     stream_change_type_ = change;
     autoscroll_ = autoscroll;
-    HandleLoadResult(url_handlers_[url.scheme()]->StartLoading(url));
+    UrlHandler *url_handler = url_handlers_.value(url.scheme());
+    HandleLoadResult(url_handler->StartLoading(url));
   }
   else {
     qLog(Debug) << "Playing song" << current_item_->Metadata().title() << url << "position" << offset_nanosec;
@@ -1003,7 +1005,8 @@ void Player::TrackAboutToEnd() {
   if (url_handlers_.contains(url.scheme())) {
     if (loading_async_.contains(url)) return;
     autoscroll_ = Playlist::AutoScroll::Maybe;
-    UrlHandler::LoadResult result = url_handlers_[url.scheme()]->StartLoading(url);
+    UrlHandler *url_handler = url_handlers_.value(url.scheme());
+    const UrlHandler::LoadResult result = url_handler->StartLoading(url);
     switch (result.type_) {
       case UrlHandler::LoadResult::Type::Error:
         emit Error(result.error_);
diff --git a/src/core/taskmanager.cpp b/src/core/taskmanager.cpp
index efa5350e9..0c3d42c5e 100644
--- a/src/core/taskmanager.cpp
+++ b/src/core/taskmanager.cpp
@@ -70,8 +70,7 @@ void TaskManager::SetTaskBlocksCollectionScans(const int id) {
     QMutexLocker l(&mutex_);
     if (!tasks_.contains(id)) return;
 
-    Task &t = tasks_[id];
-    t.blocks_collection_scans = true;
+    tasks_[id].blocks_collection_scans = true;
   }
 
   emit TasksChanged();
@@ -85,9 +84,10 @@ void TaskManager::SetTaskProgress(const int id, const quint64 progress, const qu
     QMutexLocker l(&mutex_);
     if (!tasks_.contains(id)) return;
 
-    Task &t = tasks_[id];
+    Task t = tasks_.value(id);
     t.progress = progress;
     if (max > 0) t.progress_max = max;
+    tasks_[id] = t;
   }
 
   emit TasksChanged();
@@ -99,9 +99,10 @@ void TaskManager::IncreaseTaskProgress(const int id, const quint64 progress, con
     QMutexLocker l(&mutex_);
     if (!tasks_.contains(id)) return;
 
-    Task &t = tasks_[id];
+    Task t = tasks_.value(id);
     t.progress += progress;
     if (max > 0) t.progress_max = max;
+    tasks_[id] = t;
   }
 
   emit TasksChanged();
@@ -116,7 +117,7 @@ void TaskManager::SetTaskFinished(const int id) {
     QMutexLocker l(&mutex_);
     if (!tasks_.contains(id)) return;
 
-    if (tasks_[id].blocks_collection_scans) {
+    if (tasks_.value(id).blocks_collection_scans) {
       resume_collection_watchers = true;
       QList<Task> tasks = tasks_.values();
 
@@ -139,7 +140,7 @@ quint64 TaskManager::GetTaskProgress(int id) {
   {
     QMutexLocker l(&mutex_);
     if (!tasks_.contains(id)) return 0;
-    return tasks_[id].progress;
+    return tasks_.value(id).progress;
   }
 
 }
diff --git a/src/covermanager/albumcoverfetchersearch.cpp b/src/covermanager/albumcoverfetchersearch.cpp
index 006fe587a..e3772e941 100644
--- a/src/covermanager/albumcoverfetchersearch.cpp
+++ b/src/covermanager/albumcoverfetchersearch.cpp
@@ -134,7 +134,7 @@ void AlbumCoverFetcherSearch::Start(SharedPtr<CoverProviders> cover_providers) {
 void AlbumCoverFetcherSearch::ProviderSearchResults(const int id, const CoverProviderSearchResults &results) {
 
   if (!pending_requests_.contains(id)) return;
-  CoverProvider *provider = pending_requests_[id];
+  CoverProvider *provider = pending_requests_.value(id);
   ProviderSearchResults(provider, results);
 
 }
diff --git a/src/covermanager/albumcoverloader.cpp b/src/covermanager/albumcoverloader.cpp
index e1f4abca3..b25ebab7f 100644
--- a/src/covermanager/albumcoverloader.cpp
+++ b/src/covermanager/albumcoverloader.cpp
@@ -93,7 +93,7 @@ void AlbumCoverLoader::CancelTasks(const QSet<quint64> &ids) {
 
   QMutexLocker l(&mutex_load_image_async_);
   for (QQueue<TaskPtr>::iterator it = tasks_.begin(); it != tasks_.end();) {
-    TaskPtr task = *it;
+    const TaskPtr task = *it;
     if (ids.contains(task->id)) {
       it = tasks_.erase(it);
     }
diff --git a/src/covermanager/albumcovermanager.cpp b/src/covermanager/albumcovermanager.cpp
index 00ea97c79..7052d5ccc 100644
--- a/src/covermanager/albumcovermanager.cpp
+++ b/src/covermanager/albumcovermanager.cpp
@@ -621,11 +621,11 @@ bool AlbumCoverManager::eventFilter(QObject *obj, QEvent *e) {
 }
 
 Song AlbumCoverManager::GetSingleSelectionAsSong() {
-  return context_menu_items_.size() != 1 ? Song() : AlbumItemAsSong(context_menu_items_[0]);
+  return context_menu_items_.size() != 1 ? Song() : AlbumItemAsSong(context_menu_items_.value(0));
 }
 
 Song AlbumCoverManager::GetFirstSelectedAsSong() {
-  return context_menu_items_.isEmpty() ? Song() : AlbumItemAsSong(context_menu_items_[0]);
+  return context_menu_items_.isEmpty() ? Song() : AlbumItemAsSong(context_menu_items_.value(0));
 }
 
 Song AlbumCoverManager::AlbumItemAsSong(AlbumItem *album_item) {
@@ -646,7 +646,7 @@ Song AlbumCoverManager::AlbumItemAsSong(AlbumItem *album_item) {
   result.set_album(album_item->data(Role_Album).toString());
 
   result.set_filetype(static_cast<Song::FileType>(album_item->data(Role_Filetype).toInt()));
-  result.set_url(album_item->urls.first());
+  result.set_url(album_item->urls.constFirst());
   result.set_cue_path(album_item->data(Role_CuePath).toString());
 
   result.set_art_embedded(album_item->data(Role_ArtEmbedded).toBool());
@@ -1085,7 +1085,7 @@ void AlbumCoverManager::LoadAlbumCoverAsync(AlbumItem *album_item) {
   cover_options.types = cover_types_;
   cover_options.desired_scaled_size = QSize(kThumbnailSize, kThumbnailSize);
   cover_options.device_pixel_ratio = devicePixelRatioF();
-  quint64 cover_load_id = app_->album_cover_loader()->LoadImageAsync(cover_options, album_item->data(Role_ArtEmbedded).toBool(), album_item->data(Role_ArtAutomatic).toUrl(), album_item->data(Role_ArtManual).toUrl(), album_item->data(Role_ArtUnset).toBool(), album_item->urls.first());
+  quint64 cover_load_id = app_->album_cover_loader()->LoadImageAsync(cover_options, album_item->data(Role_ArtEmbedded).toBool(), album_item->data(Role_ArtAutomatic).toUrl(), album_item->data(Role_ArtManual).toUrl(), album_item->data(Role_ArtUnset).toBool(), album_item->urls.constFirst());
   cover_loading_tasks_.insert(cover_load_id, album_item);
 
 }
diff --git a/src/device/devicemanager.cpp b/src/device/devicemanager.cpp
index 207689c87..df263978b 100644
--- a/src/device/devicemanager.cpp
+++ b/src/device/devicemanager.cpp
@@ -830,7 +830,7 @@ void DeviceManager::DeviceTaskStarted(const int id) {
   if (!device) return;
 
   for (int i = 0; i < devices_.count(); ++i) {
-    DeviceInfo *info = devices_[i];
+    DeviceInfo *info = devices_.value(i);
     if (info->device_ && &*info->device_ == device) {
       QModelIndex index = ItemToIndex(info);
       if (!index.isValid()) continue;
@@ -851,7 +851,7 @@ void DeviceManager::TasksChanged() {
   for (const TaskManager::Task &task : tasks) {
     if (!active_tasks_.contains(task.id)) continue;
 
-    const QPersistentModelIndex idx = active_tasks_[task.id];
+    const QPersistentModelIndex idx = active_tasks_.value(task.id);
     if (!idx.isValid()) continue;
 
     DeviceInfo *info = IndexToItem(idx);
diff --git a/src/device/giolister.cpp b/src/device/giolister.cpp
index 06aa43381..1ee238a65 100644
--- a/src/device/giolister.cpp
+++ b/src/device/giolister.cpp
@@ -144,14 +144,14 @@ QVariantList GioLister::DeviceIcons(const QString &id) {
   QMutexLocker l(&mutex_);
   if (!devices_.contains(id)) return ret;
 
-  const DeviceInfo &info = devices_[id];
+  const DeviceInfo device_info = devices_.value(id);
 
-  if (info.mount_ptr) {
-    ret << DeviceLister::GuessIconForPath(info.mount_path);
-    ret << info.mount_icon_names;
+  if (device_info.mount_ptr) {
+    ret << DeviceLister::GuessIconForPath(device_info.mount_path);
+    ret << device_info.mount_icon_names;
   }
 
-  ret << DeviceLister::GuessIconForModel(QString(), info.mount_name);
+  ret << DeviceLister::GuessIconForModel(QString(), device_info.mount_name);
 
   return ret;
 
@@ -163,9 +163,9 @@ QString GioLister::DeviceModel(const QString &id) {
 
   QMutexLocker l(&mutex_);
   if (!devices_.contains(id)) return QString();
-  const DeviceInfo &info = devices_[id];
+  const DeviceInfo device_info = devices_.value(id);
 
-  return info.drive_name.isEmpty() ? info.volume_name : info.drive_name;
+  return device_info.drive_name.isEmpty() ? device_info.volume_name : device_info.drive_name;
 
 }
 
@@ -187,7 +187,7 @@ QVariantMap GioLister::DeviceHardwareInfo(const QString &id) {
 
   QMutexLocker l(&mutex_);
   if (!devices_.contains(id)) return ret;
-  const DeviceInfo &info = devices_[id];
+  const DeviceInfo info = devices_.value(id);
 
   ret[QStringLiteral(QT_TR_NOOP("Mount point"))] = info.mount_path;
   ret[QStringLiteral(QT_TR_NOOP("Device"))] = info.volume_unix_device;
@@ -399,7 +399,7 @@ void GioLister::MountChanged(GMount *mount) {
     new_info.ReadDriveInfo(g_mount_get_drive(mount));
 
     // Ignore the change if the new info is useless
-    if (new_info.invalid_enclosing_mount || (devices_[id].filesystem_size != 0 && new_info.filesystem_size == 0) || (!devices_[id].filesystem_type.isEmpty() && new_info.filesystem_type.isEmpty())) {
+    if (new_info.invalid_enclosing_mount || (devices_.value(id).filesystem_size != 0 && new_info.filesystem_size == 0) || (!devices_[id].filesystem_type.isEmpty() && new_info.filesystem_type.isEmpty())) {
       return;
     }
 
@@ -577,11 +577,9 @@ void GioLister::UpdateDeviceFreeSpace(const QString &id) {
 
   {
     QMutexLocker l(&mutex_);
-    if (!devices_.contains(id) || !devices_[id].mount_ptr || devices_[id].volume_root_uri.startsWith(QLatin1String("mtp://"))) return;
+    if (!devices_.contains(id) || !devices_[id].mount_ptr || devices_.value(id).volume_root_uri.startsWith(QLatin1String("mtp://"))) return;
 
-    DeviceInfo &device_info = devices_[id];
-
-    GFile *root = g_mount_get_root(device_info.mount_ptr);
+    GFile *root = g_mount_get_root(devices_.value(id).mount_ptr);
 
     GError *error = nullptr;
     GFileInfo *info = g_file_query_filesystem_info(root, G_FILE_ATTRIBUTE_FILESYSTEM_FREE, nullptr, &error);
@@ -590,7 +588,7 @@ void GioLister::UpdateDeviceFreeSpace(const QString &id) {
       g_error_free(error);
     }
     else {
-      device_info.filesystem_free = g_file_info_get_attribute_uint64(info, G_FILE_ATTRIBUTE_FILESYSTEM_FREE);
+      devices_[id].filesystem_free = g_file_info_get_attribute_uint64(info, G_FILE_ATTRIBUTE_FILESYSTEM_FREE);
       g_object_unref(info);
     }
 
@@ -616,14 +614,14 @@ void GioLister::MountDevice(const QString &id, const int request_id) {
     return;
   }
 
-  const DeviceInfo &info = devices_[id];
-  if (info.mount_ptr) {
+  const DeviceInfo device_info = devices_.value(id);
+  if (device_info.mount_ptr) {
     // Already mounted
     emit DeviceMounted(id, request_id, true);
     return;
   }
 
-  g_volume_mount(info.volume_ptr, G_MOUNT_MOUNT_NONE, nullptr, nullptr, VolumeMountFinished, nullptr);
+  g_volume_mount(device_info.volume_ptr, G_MOUNT_MOUNT_NONE, nullptr, nullptr, VolumeMountFinished, nullptr);
   emit DeviceMounted(id, request_id, true);
 
 }
@@ -631,25 +629,25 @@ void GioLister::MountDevice(const QString &id, const int request_id) {
 void GioLister::UnmountDevice(const QString &id) {
 
   QMutexLocker l(&mutex_);
-  if (!devices_.contains(id) || !devices_[id].mount_ptr || devices_[id].volume_root_uri.startsWith(QLatin1String("mtp://"))) return;
+  if (!devices_.contains(id) || !devices_[id].mount_ptr || devices_.value(id).volume_root_uri.startsWith(QLatin1String("mtp://"))) return;
 
-  const DeviceInfo &info = devices_[id];
+  const DeviceInfo device_info = devices_.value(id);
 
-  if (!info.mount_ptr) return;
+  if (!device_info.mount_ptr) return;
 
-  if (info.volume_ptr) {
-    if (g_volume_can_eject(info.volume_ptr)) {
-      g_volume_eject_with_operation(info.volume_ptr, G_MOUNT_UNMOUNT_NONE, nullptr, nullptr, reinterpret_cast<GAsyncReadyCallback>(VolumeEjectFinished), nullptr);
+  if (device_info.volume_ptr) {
+    if (g_volume_can_eject(device_info.volume_ptr)) {
+      g_volume_eject_with_operation(device_info.volume_ptr, G_MOUNT_UNMOUNT_NONE, nullptr, nullptr, reinterpret_cast<GAsyncReadyCallback>(VolumeEjectFinished), nullptr);
       return;
     }
   }
   else return;
 
-  if (g_mount_can_eject(info.mount_ptr)) {
-    g_mount_eject_with_operation(info.mount_ptr, G_MOUNT_UNMOUNT_NONE, nullptr, nullptr, reinterpret_cast<GAsyncReadyCallback>(MountEjectFinished), nullptr);
+  if (g_mount_can_eject(device_info.mount_ptr)) {
+    g_mount_eject_with_operation(device_info.mount_ptr, G_MOUNT_UNMOUNT_NONE, nullptr, nullptr, reinterpret_cast<GAsyncReadyCallback>(MountEjectFinished), nullptr);
   }
-  else if (g_mount_can_unmount(info.mount_ptr)) {
-    g_mount_unmount_with_operation(info.mount_ptr, G_MOUNT_UNMOUNT_NONE, nullptr, nullptr, reinterpret_cast<GAsyncReadyCallback>(MountUnmountFinished), nullptr);
+  else if (g_mount_can_unmount(device_info.mount_ptr)) {
+    g_mount_unmount_with_operation(device_info.mount_ptr, G_MOUNT_UNMOUNT_NONE, nullptr, nullptr, reinterpret_cast<GAsyncReadyCallback>(MountUnmountFinished), nullptr);
   }
 
 }
diff --git a/src/device/giolister.h b/src/device/giolister.h
index e514cad9d..f863ce53e 100644
--- a/src/device/giolister.h
+++ b/src/device/giolister.h
@@ -148,7 +148,7 @@ T GioLister::LockAndGetDeviceInfo(const QString &id, T DeviceInfo::*field) {
   QMutexLocker l(&mutex_);
   if (!devices_.contains(id)) return T();
 
-  return devices_[id].*field;
+  return devices_.value(id).*field;
 }
 
 #endif  // GIOLISTER_H
diff --git a/src/device/udisks2lister.cpp b/src/device/udisks2lister.cpp
index 410ceb38a..ba546296c 100644
--- a/src/device/udisks2lister.cpp
+++ b/src/device/udisks2lister.cpp
@@ -74,7 +74,7 @@ QVariantList Udisks2Lister::DeviceIcons(const QString &id) {
 
   QReadLocker locker(&device_data_lock_);
   if (!device_data_.contains(id)) return QVariantList();
-  QString path = device_data_[id].mount_paths.at(0);
+  const QString path = device_data_.value(id).mount_paths.value(0);
 
   return QVariantList() << GuessIconForPath(path) << GuessIconForModel(DeviceManufacturer(id), DeviceModel(id));
 
@@ -84,7 +84,7 @@ QString Udisks2Lister::DeviceManufacturer(const QString &id) {
 
   QReadLocker locker(&device_data_lock_);
   if (!device_data_.contains(id)) return QLatin1String("");
-  return device_data_[id].vendor;
+  return device_data_.value(id).vendor;
 
 }
 
@@ -92,7 +92,7 @@ QString Udisks2Lister::DeviceModel(const QString &id) {
 
   QReadLocker locker(&device_data_lock_);
   if (!device_data_.contains(id)) return QLatin1String("");
-  return device_data_[id].model;
+  return device_data_.value(id).model;
 
 }
 
@@ -100,7 +100,7 @@ quint64 Udisks2Lister::DeviceCapacity(const QString &id) {
 
   QReadLocker locker(&device_data_lock_);
   if (!device_data_.contains(id)) return 0;
-  return device_data_[id].capacity;
+  return device_data_.value(id).capacity;
 
 }
 
@@ -108,7 +108,7 @@ quint64 Udisks2Lister::DeviceFreeSpace(const QString &id) {
 
   QReadLocker locker(&device_data_lock_);
   if (!device_data_.contains(id)) return 0;
-  return device_data_[id].free_space;
+  return device_data_.value(id).free_space;
 
 }
 
@@ -119,7 +119,7 @@ QVariantMap Udisks2Lister::DeviceHardwareInfo(const QString &id) {
 
   QVariantMap result;
 
-  const PartitionData &data = device_data_[id];
+  const PartitionData data = device_data_.value(id);
   result[QStringLiteral(QT_TR_NOOP("D-Bus path"))] = data.dbus_path;
   result[QStringLiteral(QT_TR_NOOP("Serial number"))] = data.serial;
   result[QStringLiteral(QT_TR_NOOP("Mount points"))] = data.mount_paths.join(QLatin1String(", "));
@@ -134,7 +134,7 @@ QString Udisks2Lister::MakeFriendlyName(const QString &id) {
 
   QReadLocker locker(&device_data_lock_);
   if (!device_data_.contains(id)) return QLatin1String("");
-  return device_data_[id].friendly_name;
+  return device_data_.value(id).friendly_name;
 
 }
 
@@ -153,7 +153,7 @@ void Udisks2Lister::UnmountDevice(const QString &id) {
   QReadLocker locker(&device_data_lock_);
   if (!device_data_.contains(id)) return;
 
-  OrgFreedesktopUDisks2FilesystemInterface filesystem(QLatin1String(kUDisks2Service), device_data_[id].dbus_path, QDBusConnection::systemBus());
+  OrgFreedesktopUDisks2FilesystemInterface filesystem(QLatin1String(kUDisks2Service), device_data_.value(id).dbus_path, QDBusConnection::systemBus());
 
   if (filesystem.isValid()) {
     auto unmount_result = filesystem.Unmount(QVariantMap());
@@ -164,7 +164,7 @@ void Udisks2Lister::UnmountDevice(const QString &id) {
       return;
     }
 
-    OrgFreedesktopUDisks2DriveInterface drive(QLatin1String(kUDisks2Service), device_data_[id].dbus_drive_path, QDBusConnection::systemBus());
+    OrgFreedesktopUDisks2DriveInterface drive(QLatin1String(kUDisks2Service), device_data_.value(id).dbus_drive_path, QDBusConnection::systemBus());
 
     if (drive.isValid()) {
       auto eject_result = drive.Eject(QVariantMap());
@@ -183,7 +183,7 @@ void Udisks2Lister::UnmountDevice(const QString &id) {
 
 void Udisks2Lister::UpdateDeviceFreeSpace(const QString &id) {
   QWriteLocker locker(&device_data_lock_);
-  device_data_[id].free_space = Utilities::FileSystemFreeSpace(device_data_[id].mount_paths.at(0));
+  device_data_[id].free_space = Utilities::FileSystemFreeSpace(device_data_.value(id).mount_paths.value(0));
   emit DeviceChanged(id);
 }
 
@@ -326,11 +326,12 @@ void Udisks2Lister::JobCompleted(const bool success, const QString &message) {
 
   qLog(Debug) << "Pending Job Completed | Path = " << job->path() << " | Mount? = " << mounting_jobs_[jobPath].is_mount << " | Success = " << success;
 
-  for (const auto &mounted_object : std::as_const(mounting_jobs_[jobPath].mounted_partitions)) {
+  const QList<QDBusObjectPath> mounted_partitions = mounting_jobs_.value(jobPath).mounted_partitions;
+  for (const QDBusObjectPath &mounted_object : mounted_partitions) {
     auto partition_data = ReadPartitionData(mounted_object);
     if (partition_data.dbus_path.isEmpty()) continue;
 
-    mounting_jobs_[jobPath].is_mount ? HandleFinishedMountJob(partition_data) : HandleFinishedUnmountJob(partition_data, mounted_object);
+    mounting_jobs_.value(jobPath).is_mount ? HandleFinishedMountJob(partition_data) : HandleFinishedUnmountJob(partition_data, mounted_object);
   }
 
 }
diff --git a/src/dialogs/edittagdialog.cpp b/src/dialogs/edittagdialog.cpp
index a716f92a9..e65083e78 100644
--- a/src/dialogs/edittagdialog.cpp
+++ b/src/dialogs/edittagdialog.cpp
@@ -548,7 +548,7 @@ void EditTagDialog::InitFieldValue(const FieldData &field, const QModelIndexList
       editor->set_partially();
     }
     else {
-      editor->set_value(data_[sel[0].row()].current_value(field.id_));
+      editor->set_value(data_.value(sel.value(0).row()).current_value(field.id_));
     }
   }
   else if (field.editor_) {
@@ -601,8 +601,9 @@ void EditTagDialog::ResetFieldValue(const FieldData &field, const QModelIndexLis
 
   // Reset each selected song
   for (const QModelIndex &i : sel) {
-    Data &tag_data = data_[i.row()];
+    Data tag_data = data_.value(i.row());
     tag_data.set_value(field.id_, tag_data.original_value(field.id_));
+    data_[i.row()] = tag_data;
   }
 
   // Reset the field
@@ -634,8 +635,8 @@ void EditTagDialog::SelectionChanged() {
     UpdateStatisticsTab(data_[indexes.first().row()].original_);
   }
 
-  const Song &first_song = data_[indexes.first().row()].original_;
-  UpdateCoverAction first_cover_action = data_[indexes.first().row()].cover_action_;
+  const Song first_song = data_.value(indexes.first().row()).original_;
+  const UpdateCoverAction first_cover_action = data_.value(indexes.first().row()).cover_action_;
   bool art_different = false;
   bool action_different = false;
   bool albumartist_enabled = false;
@@ -648,14 +649,14 @@ void EditTagDialog::SelectionChanged() {
   bool comment_enabled = false;
   bool lyrics_enabled = false;
   for (const QModelIndex &idx : indexes) {
-    if (data_[idx.row()].cover_action_ == UpdateCoverAction::None) {
+    if (data_.value(idx.row()).cover_action_ == UpdateCoverAction::None) {
       data_[idx.row()].cover_result_ = AlbumCoverImageResult();
     }
-    const Song &song = data_[idx.row()].original_;
-    if (data_[idx.row()].cover_action_ != first_cover_action || (first_cover_action != UpdateCoverAction::None && data_[idx.row()].cover_result_.image_data != data_[indexes.first().row()].cover_result_.image_data)) {
+    const Song song = data_.value(idx.row()).original_;
+    if (data_.value(idx.row()).cover_action_ != first_cover_action || (first_cover_action != UpdateCoverAction::None && data_[idx.row()].cover_result_.image_data != data_[indexes.first().row()].cover_result_.image_data)) {
       action_different = true;
     }
-    if (data_[idx.row()].cover_action_ != first_cover_action ||
+    if (data_.value(idx.row()).cover_action_ != first_cover_action ||
         song.art_manual() != first_song.art_manual() ||
         song.art_embedded() != first_song.art_embedded() ||
         song.art_automatic() != first_song.art_automatic() ||
@@ -733,7 +734,7 @@ void EditTagDialog::SelectionChanged() {
     cover_options.types = cover_types_;
     cover_options.desired_scaled_size = QSize(kSmallImageSize, kSmallImageSize);
     cover_options.device_pixel_ratio = devicePixelRatioF();
-    if (data_[indexes.first().row()].cover_action_ == UpdateCoverAction::None) {
+    if (data_.value(indexes.first().row()).cover_action_ == UpdateCoverAction::None) {
       tags_cover_art_id_ = app_->album_cover_loader()->LoadImageAsync(cover_options, first_song);
     }
     else {
@@ -933,8 +934,8 @@ void EditTagDialog::AlbumCoverLoaded(const quint64 id, const AlbumCoverLoaderRes
     for (const QModelIndex &idx : indexes) {
       data_[idx.row()].cover_result_ = result.album_cover;
       if (!first_song.is_valid()) {
-        first_song = data_[idx.row()].current_;
-        cover_action = data_[idx.row()].cover_action_;
+        first_song = data_.value(idx.row()).current_;
+        cover_action = data_.value(idx.row()).cover_action_;
       }
     }
     bool enable_change_art = false;
@@ -1023,7 +1024,7 @@ void EditTagDialog::SaveCoverToFile() {
 
   if (ui_->song_list->selectionModel()->selectedIndexes().isEmpty()) return;
 
-  const Data &first_data = data_[ui_->song_list->selectionModel()->selectedIndexes().first().row()];
+  const Data first_data = data_.value(ui_->song_list->selectionModel()->selectedIndexes().first().row());
   album_cover_choice_controller_->SaveCoverToFileManual(first_data.current_, first_data.cover_result_);
 
 }
@@ -1084,7 +1085,7 @@ void EditTagDialog::DeleteCover() {
 void EditTagDialog::ShowCover() {
 
   if (ui_->song_list->selectionModel()->selectedIndexes().isEmpty()) return;
-  const Data &first_data = data_[ui_->song_list->selectionModel()->selectedIndexes().first().row()];
+  const Data first_data = data_.value(ui_->song_list->selectionModel()->selectedIndexes().first().row());
   album_cover_choice_controller_->ShowCover(first_data.current_, first_data.cover_result_.image);
 
 }
@@ -1094,8 +1095,8 @@ void EditTagDialog::UpdateCover(const UpdateCoverAction cover_action, const Albu
   const QModelIndexList indexes = ui_->song_list->selectionModel()->selectedIndexes();
   if (indexes.isEmpty()) return;
 
-  QString artist = data_[indexes.first().row()].current_.effective_albumartist();
-  QString album = data_[indexes.first().row()].current_.album();
+  QString artist = data_.value(indexes.first().row()).current_.effective_albumartist();
+  QString album = data_.value(indexes.first().row()).current_.album();
 
   for (const QModelIndex &idx : indexes) {
     data_[idx.row()].cover_action_ = cover_action;
@@ -1372,7 +1373,7 @@ void EditTagDialog::FetchTag() {
   SongList songs;
 
   for (const QModelIndex &idx : sel) {
-    Song song = data_[idx.row()].original_;
+    const Song song = data_.value(idx.row()).original_;
     if (!song.is_valid()) {
       continue;
     }
@@ -1429,7 +1430,7 @@ void EditTagDialog::FetchTagSongChosen(const Song &original_song, const Song &ne
 void EditTagDialog::FetchLyrics() {
 
   if (ui_->song_list->selectionModel()->selectedIndexes().isEmpty()) return;
-  const Song &song = data_[ui_->song_list->selectionModel()->selectedIndexes().first().row()].current_;
+  const Song song = data_.value(ui_->song_list->selectionModel()->selectedIndexes().first().row()).current_;
   lyrics_fetcher_->Clear();
   ui_->lyrics->setPlainText(tr("loading..."));
   lyrics_id_ = static_cast<qint64>(lyrics_fetcher_->Search(song.effective_albumartist(), song.artist(), song.album(), song.title()));
diff --git a/src/dialogs/trackselectiondialog.cpp b/src/dialogs/trackselectiondialog.cpp
index 39d0817b4..b868ee126 100644
--- a/src/dialogs/trackselectiondialog.cpp
+++ b/src/dialogs/trackselectiondialog.cpp
@@ -174,7 +174,7 @@ void TrackSelectionDialog::UpdateStack() {
   const int row = ui_->song_list->currentRow();
   if (row < 0 || row >= data_.count()) return;
 
-  const Data &tag_data = data_[row];
+  const Data tag_data = data_.value(row);
 
   if (tag_data.pending_) {
     ui_->stack->setCurrentWidget(ui_->loading_page);
diff --git a/src/engine/gstengine.cpp b/src/engine/gstengine.cpp
index 7f1c2b398..d3b30f226 100644
--- a/src/engine/gstengine.cpp
+++ b/src/engine/gstengine.cpp
@@ -929,7 +929,7 @@ void GstEngine::PipelineFinished(const int pipeline_id) {
 
   qLog(Debug) << "Pipeline" << pipeline_id << "finished";
 
-  GstEnginePipelinePtr pipeline = old_pipelines_[pipeline_id];
+  GstEnginePipelinePtr pipeline = old_pipelines_.value(pipeline_id);
   old_pipelines_.remove(pipeline_id);
   if (pipeline == fadeout_pause_pipeline_) {
     StopFadeoutPause();
diff --git a/src/engine/gstenginepipeline.cpp b/src/engine/gstenginepipeline.cpp
index 36b238b4f..54aee71ca 100644
--- a/src/engine/gstenginepipeline.cpp
+++ b/src/engine/gstenginepipeline.cpp
@@ -1947,7 +1947,7 @@ void GstEnginePipeline::UpdateEqualizer() {
 
   // Update band gains
   for (int i = 0; i < kEqBandCount; ++i) {
-    float gain = eq_enabled_ ? static_cast<float>(eq_band_gains_[i]) : static_cast<float>(0.0);
+    float gain = eq_enabled_ ? static_cast<float>(eq_band_gains_.value(i)) : static_cast<float>(0.0);
     if (gain < 0) {
       gain *= 0.24F;
     }
diff --git a/src/equalizer/equalizer.cpp b/src/equalizer/equalizer.cpp
index 7e6179bfa..92ee86965 100644
--- a/src/equalizer/equalizer.cpp
+++ b/src/equalizer/equalizer.cpp
@@ -185,7 +185,7 @@ void Equalizer::PresetChanged(const QString &name) {
   }
   last_preset_ = name;
 
-  Params &p = presets_[name];
+  const Params p = presets_.value(name);
 
   loading_ = true;
   preamp_->set_value(p.preamp);
diff --git a/src/lyrics/lyricsfetchersearch.cpp b/src/lyrics/lyricsfetchersearch.cpp
index c5276bb16..777db68e7 100644
--- a/src/lyrics/lyricsfetchersearch.cpp
+++ b/src/lyrics/lyricsfetchersearch.cpp
@@ -135,7 +135,7 @@ void LyricsFetcherSearch::AllProvidersFinished() {
 
   if (!results_.isEmpty()) {
     qLog(Debug) << "Using lyrics from" << results_.last().provider << "for" << request_.artist << request_.title << "with score" << results_.last().score;
-    emit LyricsFetched(id_, results_.last().provider, results_.last().lyrics);
+    emit LyricsFetched(id_, results_.constLast().provider, results_.constLast().lyrics);
   }
   else {
     emit LyricsFetched(id_, QString(), QString());
diff --git a/src/moodbar/moodbarbuilder.cpp b/src/moodbar/moodbarbuilder.cpp
index e6980a6ce..de326c166 100644
--- a/src/moodbar/moodbarbuilder.cpp
+++ b/src/moodbar/moodbarbuilder.cpp
@@ -177,10 +177,11 @@ QByteArray MoodbarBuilder::Finish(int width) {
     const int end = std::max(static_cast<int>((i + 1) * frames_.count() / width), start + 1);
 
     for (int j = start; j < end; j++) {
-      const Rgb &frame = frames_[j];
+      const Rgb frame = frames_.value(j);
       rgb.r += frame.r * 255;
       rgb.g += frame.g * 255;
       rgb.b += frame.b * 255;
+      frames_[j] = rgb;
     }
 
     const int n = end - start;
diff --git a/src/moodbar/moodbarloader.cpp b/src/moodbar/moodbarloader.cpp
index 4e1ef7e1c..eecc2b236 100644
--- a/src/moodbar/moodbarloader.cpp
+++ b/src/moodbar/moodbarloader.cpp
@@ -107,7 +107,7 @@ MoodbarLoader::Result MoodbarLoader::Load(const QUrl &url, const bool has_cue, Q
 
   // Are we in the middle of loading this moodbar already?
   if (requests_.contains(url)) {
-    *async_pipeline = requests_[url];
+    *async_pipeline = requests_.value(url);
     return Result::WillLoadAsync;
   }
 
@@ -173,7 +173,7 @@ void MoodbarLoader::MaybeTakeNextRequest() {
   active_requests_ << url;
 
   qLog(Info) << "Creating moodbar data for" << url.toLocalFile();
-  QMetaObject::invokeMethod(requests_[url], &MoodbarPipeline::Start, Qt::QueuedConnection);
+  QMetaObject::invokeMethod(requests_.value(url), &MoodbarPipeline::Start, Qt::QueuedConnection);
 
 }
 
diff --git a/src/musicbrainz/tagfetcher.cpp b/src/musicbrainz/tagfetcher.cpp
index e2f9a8fa2..8438d40cb 100644
--- a/src/musicbrainz/tagfetcher.cpp
+++ b/src/musicbrainz/tagfetcher.cpp
@@ -66,7 +66,7 @@ void TagFetcher::StartFetch(const SongList &songs) {
 
   if (have_fingerprints) {
     for (int i = 0; i < songs_.count(); ++i) {
-      const Song &song = songs_[i];
+      const Song song = songs_.value(i);
       emit Progress(song, tr("Identifying song"));
       acoustid_client_->Start(i, song.fingerprint(), static_cast<int>(song.length_nanosec() / kNsecPerMsec));
     }
@@ -104,7 +104,7 @@ void TagFetcher::FingerprintFound(const int index) {
   if (!watcher || index >= songs_.count()) return;
 
   const QString fingerprint = watcher->resultAt(index);
-  const Song &song = songs_[index];
+  const Song song = songs_.value(index);
 
   if (fingerprint.isEmpty()) {
     emit ResultAvailable(song, SongList());
@@ -122,7 +122,7 @@ void TagFetcher::PuidsFound(const int index, const QStringList &puid_list, const
     return;
   }
 
-  const Song &song = songs_[index];
+  const Song song = songs_.value(index);
 
   if (puid_list.isEmpty()) {
     emit ResultAvailable(song, SongList(), error);
@@ -140,7 +140,7 @@ void TagFetcher::TagsFetched(const int index, const MusicBrainzClient::ResultLis
     return;
   }
 
-  const Song &original_song = songs_[index];
+  const Song original_song = songs_.value(index);
   SongList songs_guessed;
   songs_guessed.reserve(results.count());
   for (const MusicBrainzClient::Result &result : results) {
diff --git a/src/osd/osdpretty.cpp b/src/osd/osdpretty.cpp
index c89a85044..a85e73f72 100644
--- a/src/osd/osdpretty.cpp
+++ b/src/osd/osdpretty.cpp
@@ -251,7 +251,7 @@ void OSDPretty::Load() {
   if (s.contains(QLatin1String("popup_screen"))) {
     popup_screen_name_ = s.value("popup_screen").toString();
     if (screens_.contains(popup_screen_name_)) {
-      popup_screen_ = screens_[popup_screen_name_];
+      popup_screen_ = screens_.value(popup_screen_name_);
     }
     else {
       popup_screen_ = current_screen();
diff --git a/src/playlist/playlist.cpp b/src/playlist/playlist.cpp
index 3f14ac7b2..1116815e8 100644
--- a/src/playlist/playlist.cpp
+++ b/src/playlist/playlist.cpp
@@ -620,7 +620,7 @@ int Playlist::next_row(const bool ignore_repeat_track) {
   // Still off the end?  Then just give up
   if (next_virtual_index < 0 || next_virtual_index >= virtual_items_.count()) return -1;
 
-  return virtual_items_[next_virtual_index];
+  return virtual_items_.value(next_virtual_index);
 
 }
 
@@ -651,7 +651,7 @@ int Playlist::previous_row(const bool ignore_repeat_track) {
   // Still off the beginning?  Then just give up
   if (prev_virtual_index < 0) return -1;
 
-  return virtual_items_[prev_virtual_index];
+  return virtual_items_.value(prev_virtual_index);
 
 }
 
@@ -1227,7 +1227,7 @@ void Playlist::UpdateItems(SongList songs) {
     QMutableListIterator<Song> it(songs);
     while (it.hasNext()) {
       const Song &song = it.next();
-      const PlaylistItemPtr &item = items_[i];
+      const PlaylistItemPtr item = items_.value(i);
       if (item->Metadata().url() == song.url() && (item->Metadata().filetype() == Song::FileType::Unknown || item->Metadata().filetype() == Song::FileType::Stream || item->Metadata().filetype() == Song::FileType::CDDA || !item->Metadata().init_from_file())) {
         PlaylistItemPtr new_item;
         if (song.url().isLocalFile()) {
@@ -2315,7 +2315,7 @@ void Playlist::InvalidateDeletedSongs() {
   QList<int> invalidated_rows;
 
   for (int row = 0; row < items_.count(); ++row) {
-    PlaylistItemPtr item = items_[row];
+    PlaylistItemPtr item = items_.value(row);
     Song song = item->Metadata();
 
     if (song.url().isLocalFile()) {
@@ -2349,7 +2349,7 @@ void Playlist::RemoveDeletedSongs() {
   QList<int> rows_to_remove;
 
   for (int row = 0; row < items_.count(); ++row) {
-    PlaylistItemPtr item = items_[row];
+    PlaylistItemPtr item = items_.value(row);
     Song song = item->Metadata();
 
     if (song.url().isLocalFile() && !QFile::exists(song.url().toLocalFile())) {
@@ -2383,7 +2383,7 @@ void Playlist::RemoveDuplicateSongs() {
   std::unordered_map<Song, int, SongSimilarHash, SongSimilarEqual> unique_songs;
 
   for (int row = 0; row < items_.count(); ++row) {
-    PlaylistItemPtr item = items_[row];
+    PlaylistItemPtr item = items_.value(row);
     const Song &song = item->Metadata();
 
     bool found_duplicate = false;
@@ -2416,7 +2416,7 @@ void Playlist::RemoveUnavailableSongs() {
 
   QList<int> rows_to_remove;
   for (int row = 0; row < items_.count(); ++row) {
-    PlaylistItemPtr item = items_[row];
+    PlaylistItemPtr item = items_.value(row);
     const Song &song = item->Metadata();
 
     // Check only local files
diff --git a/src/playlist/playlistlistmodel.cpp b/src/playlist/playlistlistmodel.cpp
index 01458f191..5415045c5 100644
--- a/src/playlist/playlistlistmodel.cpp
+++ b/src/playlist/playlistlistmodel.cpp
@@ -135,7 +135,7 @@ void PlaylistListModel::RowsAboutToBeRemoved(const QModelIndex &parent, const in
         const int id = idx.data(Role_PlaylistId).toInt();
         QMap<int, QStandardItem*>::iterator it = playlists_by_id_.find(id);
         if (it != playlists_by_id_.end() && it.value() == item) {
-          playlists_by_id_.erase(it);  // clazy:exclude=strict-iterators
+          playlists_by_id_.erase(it);
         }
         break;
       }
diff --git a/src/playlist/playlistmanager.cpp b/src/playlist/playlistmanager.cpp
index 3eda0f74a..7dac0227f 100644
--- a/src/playlist/playlistmanager.cpp
+++ b/src/playlist/playlistmanager.cpp
@@ -431,7 +431,8 @@ void PlaylistManager::UpdateSummaryText() {
   int selected = 0;
 
   // Get the length of the selected tracks
-  for (const QItemSelectionRange &range : std::as_const(playlists_[current_id()].selection)) {
+  const QItemSelection ranges = playlists_.value(current_id()).selection;
+  for (const QItemSelectionRange &range : ranges) {
     if (!range.isValid()) continue;
 
     selected += range.bottom() - range.top() + 1;
diff --git a/src/playlist/playlistundocommands.cpp b/src/playlist/playlistundocommands.cpp
index af719bd4d..a217c2d1e 100644
--- a/src/playlist/playlistundocommands.cpp
+++ b/src/playlist/playlistundocommands.cpp
@@ -57,7 +57,7 @@ void InsertItems::undo() {
 bool InsertItems::UpdateItem(const PlaylistItemPtr &updated_item) {
 
   for (int i = 0; i < items_.size(); i++) {
-    PlaylistItemPtr item = items_[i];
+    PlaylistItemPtr item = items_.value(i);
     if (item->Metadata().url() == updated_item->Metadata().url()) {
       items_[i] = updated_item;
       return true;
diff --git a/src/playlist/songloaderinserter.cpp b/src/playlist/songloaderinserter.cpp
index 30dbbf98f..d657b8dc4 100644
--- a/src/playlist/songloaderinserter.cpp
+++ b/src/playlist/songloaderinserter.cpp
@@ -177,7 +177,7 @@ void SongLoaderInserter::AsyncLoad() {
   task_manager_->SetTaskProgress(async_load_id, async_progress, pending_.count());
   bool first_loaded = false;
   for (int i = 0; i < pending_.count(); ++i) {
-    SongLoader *loader = pending_[i];
+    SongLoader *loader = pending_.value(i);
     SongLoader::Result res = loader->LoadFilenamesBlocking();
     task_manager_->SetTaskProgress(async_load_id, ++async_progress);
 
@@ -208,7 +208,7 @@ void SongLoaderInserter::AsyncLoad() {
   task_manager_->SetTaskProgress(async_load_id, async_progress, songs_.count());
   SongList songs;
   for (int i = 0; i < pending_.count(); ++i) {
-    SongLoader *loader = pending_[i];
+    SongLoader *loader = pending_.value(i);
     if (i != 0) {
       // We already did this earlier for the first song.
       loader->LoadMetadataBlocking();
diff --git a/src/qobuz/qobuzrequest.cpp b/src/qobuz/qobuzrequest.cpp
index be96db970..1b31c81e3 100644
--- a/src/qobuz/qobuzrequest.cpp
+++ b/src/qobuz/qobuzrequest.cpp
@@ -801,7 +801,7 @@ void QobuzRequest::AlbumsFinishCheck(const Artist &artist, const int limit, cons
 
     // Get songs for all the albums.
 
-    for (QHash<QString, AlbumSongsRequest>::iterator it = album_songs_requests_pending_.begin(); it != album_songs_requests_pending_.end(); ++it) {
+    for (QHash<QString, AlbumSongsRequest>::const_iterator it = album_songs_requests_pending_.constBegin(); it != album_songs_requests_pending_.constEnd(); ++it) {
       const AlbumSongsRequest &request = it.value();
       AddAlbumSongsRequest(request.artist, request.album);
     }
@@ -1366,7 +1366,7 @@ void QobuzRequest::AlbumCoverReceived(QNetworkReply *reply, const QUrl &cover_ur
   QByteArrayList format_list = QImageReader::imageFormatsForMimeType(mimetype.toUtf8());
   char *format = nullptr;
   if (!format_list.isEmpty()) {
-    format = format_list.first().data();
+    format = format_list[0].data();
   }
 
   QImage image;
diff --git a/src/qobuz/qobuzstreamurlrequest.cpp b/src/qobuz/qobuzstreamurlrequest.cpp
index 286b38b38..324672f5c 100644
--- a/src/qobuz/qobuzstreamurlrequest.cpp
+++ b/src/qobuz/qobuzstreamurlrequest.cpp
@@ -159,32 +159,32 @@ void QobuzStreamURLRequest::StreamURLReceived() {
       need_login_ = true;
       return;
     }
-    emit StreamURLFailure(id_, media_url_, errors_.first());
+    emit StreamURLFailure(id_, media_url_, errors_.constFirst());
     return;
   }
 
   QJsonObject json_obj = ExtractJsonObj(data);
   if (json_obj.isEmpty()) {
-    emit StreamURLFailure(id_, media_url_, errors_.first());
+    emit StreamURLFailure(id_, media_url_, errors_.constFirst());
     return;
   }
 
   if (!json_obj.contains(QLatin1String("track_id"))) {
     Error(QStringLiteral("Invalid Json reply, stream url is missing track_id."), json_obj);
-    emit StreamURLFailure(id_, media_url_, errors_.first());
+    emit StreamURLFailure(id_, media_url_, errors_.constFirst());
     return;
   }
 
   int track_id = json_obj[QLatin1String("track_id")].toInt();
   if (track_id != song_id_) {
     Error(QStringLiteral("Incorrect track ID returned."), json_obj);
-    emit StreamURLFailure(id_, media_url_, errors_.first());
+    emit StreamURLFailure(id_, media_url_, errors_.constFirst());
     return;
   }
 
   if (!json_obj.contains(QLatin1String("mime_type")) || !json_obj.contains(QLatin1String("url"))) {
     Error(QStringLiteral("Invalid Json reply, stream url is missing url or mime_type."), json_obj);
-    emit StreamURLFailure(id_, media_url_, errors_.first());
+    emit StreamURLFailure(id_, media_url_, errors_.constFirst());
     return;
   }
 
@@ -205,7 +205,7 @@ void QobuzStreamURLRequest::StreamURLReceived() {
 
   if (!url.isValid()) {
     Error(QStringLiteral("Returned stream url is invalid."), json_obj);
-    emit StreamURLFailure(id_, media_url_, errors_.first());
+    emit StreamURLFailure(id_, media_url_, errors_.constFirst());
     return;
   }
 
diff --git a/src/radios/radiomodel.cpp b/src/radios/radiomodel.cpp
index 5d657cc91..f08cc8e4e 100644
--- a/src/radios/radiomodel.cpp
+++ b/src/radios/radiomodel.cpp
@@ -163,7 +163,7 @@ void RadioModel::AddChannels(const RadioChannelList &channels) {
   for (const RadioChannel &channel : channels) {
     RadioItem *container = nullptr;
     if (container_nodes_.contains(channel.source)) {
-      container = container_nodes_[channel.source];
+      container = container_nodes_.value(channel.source);
     }
     else {
       beginInsertRows(ItemToIndex(root_), static_cast<int>(root_->children.count()), static_cast<int>(root_->children.count()));
diff --git a/src/scrobbler/audioscrobbler.cpp b/src/scrobbler/audioscrobbler.cpp
index 85f311b4f..b7c28de22 100644
--- a/src/scrobbler/audioscrobbler.cpp
+++ b/src/scrobbler/audioscrobbler.cpp
@@ -49,7 +49,7 @@ AudioScrobbler::AudioScrobbler(Application *app, QObject *parent)
 AudioScrobbler::~AudioScrobbler() {
 
   while (!services_.isEmpty()) {
-    ScrobblerServicePtr service = services_.first();
+    ScrobblerServicePtr service = services_.value(services_.firstKey());
     RemoveService(service);
   }
 
diff --git a/src/settings/globalshortcutssettingspage.cpp b/src/settings/globalshortcutssettingspage.cpp
index 2eff76396..d36a2c5f6 100644
--- a/src/settings/globalshortcutssettingspage.cpp
+++ b/src/settings/globalshortcutssettingspage.cpp
@@ -278,17 +278,19 @@ void GlobalShortcutsSettingsPage::OpenMateKeybindingProperties() {
 
 void GlobalShortcutsSettingsPage::SetShortcut(const QString &id, const QKeySequence &key) {
 
-  Shortcut &shortcut = shortcuts_[id];
+  Shortcut shortcut = shortcuts_.value(id);
 
   shortcut.key = key;
   shortcut.item->setText(1, key.toString(QKeySequence::NativeText));
 
+  shortcuts_[id] = shortcut;
+
 }
 
 void GlobalShortcutsSettingsPage::ItemClicked(QTreeWidgetItem *item) {
 
   current_id_ = item->data(0, Qt::UserRole).toString();
-  Shortcut &shortcut = shortcuts_[current_id_];
+  const Shortcut shortcut = shortcuts_.value(current_id_);
 
   // Enable options
   ui_->shortcut_options->setEnabled(true);
@@ -324,7 +326,7 @@ void GlobalShortcutsSettingsPage::ChangeClicked() {
 
   GlobalShortcutsManager *manager = dialog()->global_shortcuts_manager();
   manager->Unregister();
-  QKeySequence key = grabber_->GetKey(shortcuts_[current_id_].s.action->text());
+  QKeySequence key = grabber_->GetKey(shortcuts_.value(current_id_).s.action->text());
   manager->Register();
 
   if (key.isEmpty()) return;
diff --git a/src/smartplaylists/smartplaylistquerywizardplugin.cpp b/src/smartplaylists/smartplaylistquerywizardplugin.cpp
index 6022af332..d8c3b4580 100644
--- a/src/smartplaylists/smartplaylistquerywizardplugin.cpp
+++ b/src/smartplaylists/smartplaylistquerywizardplugin.cpp
@@ -186,7 +186,7 @@ void SmartPlaylistQueryWizardPlugin::SetGenerator(PlaylistGeneratorPtr g) {
 
   for (const SmartPlaylistSearchTerm &term : std::as_const(search.terms_)) {
     AddSearchTerm();
-    search_page_->terms_.last()->SetTerm(term);
+    search_page_->terms_.constLast()->SetTerm(term);
   }
 
   // Sort order
diff --git a/src/smartplaylists/smartplaylistsmodel.cpp b/src/smartplaylists/smartplaylistsmodel.cpp
index cc7f8aa7d..f1adad1b4 100644
--- a/src/smartplaylists/smartplaylistsmodel.cpp
+++ b/src/smartplaylists/smartplaylistsmodel.cpp
@@ -122,7 +122,7 @@ void SmartPlaylistsModel::Init() {
   // How many defaults do we have to write?
   int unwritten_defaults = 0;
   for (int i = version; i < default_smart_playlists_.count(); ++i) {
-    unwritten_defaults += static_cast<int>(default_smart_playlists_[i].count());
+    unwritten_defaults += static_cast<int>(default_smart_playlists_.value(i).count());
   }
 
   // Save the defaults if there are any unwritten ones
@@ -134,7 +134,8 @@ void SmartPlaylistsModel::Init() {
     // Append the new ones
     s.beginWriteArray(collection_backend_->songs_table(), playlist_index + unwritten_defaults);
     for (; version < default_smart_playlists_.count(); ++version) {
-      for (PlaylistGeneratorPtr gen : std::as_const(default_smart_playlists_[version])) {
+      const GeneratorList generators = default_smart_playlists_.value(version);
+      for (PlaylistGeneratorPtr gen : generators) {
         SaveGenerator(&s, playlist_index++, gen);
       }
     }
diff --git a/src/smartplaylists/smartplaylistwizard.cpp b/src/smartplaylists/smartplaylistwizard.cpp
index f7d38b261..574aa2391 100644
--- a/src/smartplaylists/smartplaylistwizard.cpp
+++ b/src/smartplaylists/smartplaylistwizard.cpp
@@ -110,7 +110,7 @@ void SmartPlaylistWizard::SetGenerator(PlaylistGeneratorPtr gen) {
 
   // Find the right type and jump to the start page
   for (int i = 0; i < plugins_.count(); ++i) {
-    if (plugins_[i]->type() == gen->type()) {
+    if (plugins_.value(i)->type() == gen->type()) {
       TypeChanged(i);
       // TODO: Put this back in when the setStartId is removed from the ctor next();
       break;
@@ -130,7 +130,8 @@ void SmartPlaylistWizard::SetGenerator(PlaylistGeneratorPtr gen) {
   finish_page_->ui_->dynamic->setChecked(gen->is_dynamic());
 
   // Tell the plugin to load
-  plugins_[type_index_]->SetGenerator(gen);
+  SmartPlaylistWizardPlugin *plugin = plugins_.value(type_index_);
+  plugin->SetGenerator(gen);
 
 }
 
@@ -158,7 +159,7 @@ void SmartPlaylistWizard::AddPlugin(SmartPlaylistWizardPlugin *plugin) {
 void SmartPlaylistWizard::TypeChanged(const int index) {
 
   type_index_ = index;
-  type_page_->next_id_ = plugins_[type_index_]->start_page();
+  type_page_->next_id_ = plugins_.value(type_index_)->start_page();
 
 }
 
@@ -179,7 +180,7 @@ PlaylistGeneratorPtr SmartPlaylistWizard::CreateGenerator() const {
 void SmartPlaylistWizard::initializePage(const int id) {
 
   if (id == finish_id_) {
-    finish_page_->ui_->dynamic_container->setEnabled(plugins_[type_index_]->is_dynamic());
+    finish_page_->ui_->dynamic_container->setEnabled(plugins_.value(type_index_)->is_dynamic());
   }
   QWizard::initializePage(id);
 
diff --git a/src/spotify/spotifyrequest.cpp b/src/spotify/spotifyrequest.cpp
index a4093f298..240cee219 100644
--- a/src/spotify/spotifyrequest.cpp
+++ b/src/spotify/spotifyrequest.cpp
@@ -855,7 +855,7 @@ void SpotifyRequest::AlbumsFinishCheck(const Artist &artist, const int limit, co
 
     // Get songs for all the albums.
 
-    for (QMap<QString, AlbumSongsRequest> ::iterator it = album_songs_requests_pending_.begin(); it != album_songs_requests_pending_.end(); ++it) {
+    for (QMap<QString, AlbumSongsRequest> ::const_iterator it = album_songs_requests_pending_.constBegin(); it != album_songs_requests_pending_.constEnd(); ++it) {
       AlbumSongsRequest request = it.value();
       AddAlbumSongsRequest(request.artist, request.album);
     }
@@ -1315,7 +1315,7 @@ void SpotifyRequest::AlbumCoverReceived(QNetworkReply *reply, const QString &alb
   QList<QByteArray> format_list = QImageReader::imageFormatsForMimeType(mimetype.toUtf8());
   char *format = nullptr;
   if (!format_list.isEmpty()) {
-    format = format_list.first().data();
+    format = format_list[0].data();
   }
 
   QImage image;
diff --git a/src/streaming/streamingsearchmodel.cpp b/src/streaming/streamingsearchmodel.cpp
index d567d1590..370da629c 100644
--- a/src/streaming/streamingsearchmodel.cpp
+++ b/src/streaming/streamingsearchmodel.cpp
@@ -258,7 +258,7 @@ QStandardItem *StreamingSearchModel::BuildContainers(const Song &s, QStandardIte
   key->group_[level] = display_text + unique_tag;
   QStandardItem *container = nullptr;
   if (containers_.contains(*key)) {
-    container = containers_[*key];
+    container = containers_.value(*key);
   }
   else {
     container = new QStandardItem(display_text);
diff --git a/src/streaming/streamingsearchview.cpp b/src/streaming/streamingsearchview.cpp
index b63755378..48a7d6d77 100644
--- a/src/streaming/streamingsearchview.cpp
+++ b/src/streaming/streamingsearchview.cpp
@@ -366,7 +366,7 @@ void StreamingSearchView::timerEvent(QTimerEvent *e) {
   QMap<int, DelayedSearch>::iterator it = delayed_searches_.find(e->timerId());
   if (it != delayed_searches_.end()) {
     SearchAsync(it.value().id_, it.value().query_, it.value().type_);
-    delayed_searches_.erase(it);  // clazy:exclude=strict-iterators
+    delayed_searches_.erase(it);
     return;
   }
 
@@ -517,11 +517,10 @@ void StreamingSearchView::SearchDone(const int service_id, const SongMap &songs,
 
 void StreamingSearchView::CancelSearch(const int id) {
 
-  QMap<int, DelayedSearch>::iterator it;
-  for (it = delayed_searches_.begin(); it != delayed_searches_.end(); ++it) {
+  for (QMap<int, DelayedSearch>::iterator it = delayed_searches_.begin(); it != delayed_searches_.end(); ++it) {
     if (it.value().id_ == id) {
       killTimer(it.key());
-      delayed_searches_.erase(it);  // clazy:exclude=strict-iterators
+      delayed_searches_.erase(it);
       return;
     }
   }
@@ -556,7 +555,7 @@ void StreamingSearchView::SearchError(const int id, const QString &error) {
 void StreamingSearchView::UpdateStatus(const int service_id, const QString &text) {
 
   if (!pending_searches_.contains(service_id)) return;
-  const PendingState state = pending_searches_[service_id];
+  const PendingState state = pending_searches_.value(service_id);
   const int search_id = state.orig_id_;
   if (search_id != last_search_id_) return;
   ui_->progressbar->show();
@@ -567,7 +566,7 @@ void StreamingSearchView::UpdateStatus(const int service_id, const QString &text
 void StreamingSearchView::ProgressSetMaximum(const int service_id, const int max) {
 
   if (!pending_searches_.contains(service_id)) return;
-  const PendingState state = pending_searches_[service_id];
+  const PendingState state = pending_searches_.value(service_id);
   const int search_id = state.orig_id_;
   if (search_id != last_search_id_) return;
   ui_->progressbar->setMaximum(max);
@@ -577,7 +576,7 @@ void StreamingSearchView::ProgressSetMaximum(const int service_id, const int max
 void StreamingSearchView::UpdateProgress(const int service_id, const int progress) {
 
   if (!pending_searches_.contains(service_id)) return;
-  const PendingState state = pending_searches_[service_id];
+  const PendingState state = pending_searches_.value(service_id);
   const int search_id = state.orig_id_;
   if (search_id != last_search_id_) return;
   ui_->progressbar->setValue(progress);
diff --git a/src/streaming/streamingservices.cpp b/src/streaming/streamingservices.cpp
index cd0e47da8..cd18befaf 100644
--- a/src/streaming/streamingservices.cpp
+++ b/src/streaming/streamingservices.cpp
@@ -34,7 +34,7 @@ StreamingServices::StreamingServices(QObject *parent) : QObject(parent) {}
 StreamingServices::~StreamingServices() {
 
   while (!services_.isEmpty()) {
-    StreamingServicePtr service = services_.first();
+    StreamingServicePtr service = services_.value(services_.firstKey());
     RemoveService(service);
   }
 
diff --git a/src/subsonic/subsonicrequest.cpp b/src/subsonic/subsonicrequest.cpp
index ef938af04..8fb1f298b 100644
--- a/src/subsonic/subsonicrequest.cpp
+++ b/src/subsonic/subsonicrequest.cpp
@@ -306,8 +306,8 @@ void SubsonicRequest::AlbumsFinishCheck(const int offset, const int size, const
 
   if (albums_requests_queue_.isEmpty() && albums_requests_active_ <= 0) { // Albums list is finished, get songs for all albums.
 
-    for (QHash<QString, Request> ::iterator it = album_songs_requests_pending_.begin(); it != album_songs_requests_pending_.end(); ++it) {
-      Request request = it.value();
+    for (QHash<QString, Request>::const_iterator it = album_songs_requests_pending_.constBegin(); it != album_songs_requests_pending_.constEnd(); ++it) {
+      const Request request = it.value();
       AddAlbumSongsRequest(request.artist_id, request.album_id, request.album_artist);
     }
     album_songs_requests_pending_.clear();
@@ -822,7 +822,7 @@ void SubsonicRequest::AlbumCoverReceived(QNetworkReply *reply, const AlbumCoverR
   QByteArrayList format_list = QImageReader::imageFormatsForMimeType(mimetype.toUtf8());
   char *format = nullptr;
   if (!format_list.isEmpty()) {
-    format = format_list.first().data();
+    format = format_list[0].data();
   }
 
   QImage image;
diff --git a/src/tidal/tidalrequest.cpp b/src/tidal/tidalrequest.cpp
index 33f2913df..54cb08958 100644
--- a/src/tidal/tidalrequest.cpp
+++ b/src/tidal/tidalrequest.cpp
@@ -812,7 +812,7 @@ void TidalRequest::AlbumsFinishCheck(const Artist &artist, const int limit, cons
 
     // Get songs for all the albums.
 
-    for (QHash<QString, AlbumSongsRequest>::iterator it = album_songs_requests_pending_.begin(); it != album_songs_requests_pending_.end(); ++it) {
+    for (QHash<QString, AlbumSongsRequest>::const_iterator it = album_songs_requests_pending_.constBegin(); it != album_songs_requests_pending_.constEnd(); ++it) {
       const AlbumSongsRequest &request = it.value();
       AddAlbumSongsRequest(request.artist, request.album);
     }
@@ -1302,7 +1302,7 @@ void TidalRequest::AlbumCoverReceived(QNetworkReply *reply, const QString &album
   QByteArrayList format_list = QImageReader::imageFormatsForMimeType(mimetype.toUtf8());
   char *format = nullptr;
   if (!format_list.isEmpty()) {
-    format = format_list.first().data();
+    format = format_list[0].data();
   }
 
   QImage image;
diff --git a/src/tidal/tidalstreamurlrequest.cpp b/src/tidal/tidalstreamurlrequest.cpp
index 1894165b1..4940259ce 100644
--- a/src/tidal/tidalstreamurlrequest.cpp
+++ b/src/tidal/tidalstreamurlrequest.cpp
@@ -159,19 +159,19 @@ void TidalStreamURLRequest::StreamURLReceived() {
       need_login_ = true;
       return;
     }
-    emit StreamURLFailure(id_, media_url_, errors_.first());
+    emit StreamURLFailure(id_, media_url_, errors_.constFirst());
     return;
   }
 
   QJsonObject json_obj = ExtractJsonObj(data);
   if (json_obj.isEmpty()) {
-    emit StreamURLFailure(id_, media_url_, errors_.first());
+    emit StreamURLFailure(id_, media_url_, errors_.constFirst());
     return;
   }
 
   if (!json_obj.contains(QLatin1String("trackId"))) {
     Error(QStringLiteral("Invalid Json reply, stream missing trackId."), json_obj);
-    emit StreamURLFailure(id_, media_url_, errors_.first());
+    emit StreamURLFailure(id_, media_url_, errors_.constFirst());
     return;
   }
   int track_id = json_obj[QLatin1String("trackId")].toInt();
@@ -211,7 +211,7 @@ void TidalStreamURLRequest::StreamURLReceived() {
 
       json_obj = ExtractJsonObj(data_manifest);
       if (json_obj.isEmpty()) {
-        emit StreamURLFailure(id_, media_url_, errors_.first());
+        emit StreamURLFailure(id_, media_url_, errors_.constFirst());
         return;
       }
 
@@ -220,14 +220,14 @@ void TidalStreamURLRequest::StreamURLReceived() {
         QString key_id = json_obj[QLatin1String("keyId")].toString();
         if (!encryption_type.isEmpty() && !key_id.isEmpty()) {
           Error(tr("Received URL with %1 encrypted stream from Tidal. Strawberry does not currently support encrypted streams.").arg(encryption_type));
-          emit StreamURLFailure(id_, media_url_, errors_.first());
+          emit StreamURLFailure(id_, media_url_, errors_.constFirst());
           return;
         }
       }
 
       if (!json_obj.contains(QLatin1String("mimeType"))) {
         Error(QStringLiteral("Invalid Json reply, stream url reply manifest is missing mimeType."), json_obj);
-        emit StreamURLFailure(id_, media_url_, errors_.first());
+        emit StreamURLFailure(id_, media_url_, errors_.constFirst());
         return;
       }
 
@@ -250,7 +250,7 @@ void TidalStreamURLRequest::StreamURLReceived() {
     QJsonValue json_urls = json_obj[QLatin1String("urls")];
     if (!json_urls.isArray()) {
       Error(QStringLiteral("Invalid Json reply, urls is not an array."), json_urls);
-      emit StreamURLFailure(id_, media_url_, errors_.first());
+      emit StreamURLFailure(id_, media_url_, errors_.constFirst());
       return;
     }
     const QJsonArray json_array_urls = json_urls.toArray();
@@ -273,7 +273,7 @@ void TidalStreamURLRequest::StreamURLReceived() {
     QString encryption_key = json_obj[QLatin1String("encryptionKey")].toString();
     if (!encryption_key.isEmpty()) {
       Error(tr("Received URL with encrypted stream from Tidal. Strawberry does not currently support encrypted streams."));
-      emit StreamURLFailure(id_, media_url_, errors_.first());
+      emit StreamURLFailure(id_, media_url_, errors_.constFirst());
       return;
     }
   }
@@ -283,14 +283,14 @@ void TidalStreamURLRequest::StreamURLReceived() {
     QString security_token = json_obj[QLatin1String("securityToken")].toString();
     if (!security_type.isEmpty() && !security_token.isEmpty()) {
       Error(tr("Received URL with encrypted stream from Tidal. Strawberry does not currently support encrypted streams."));
-      emit StreamURLFailure(id_, media_url_, errors_.first());
+      emit StreamURLFailure(id_, media_url_, errors_.constFirst());
       return;
     }
   }
 
   if (urls.isEmpty()) {
     Error(QStringLiteral("Missing stream urls."), json_obj);
-    emit StreamURLFailure(id_, media_url_, errors_.first());
+    emit StreamURLFailure(id_, media_url_, errors_.constFirst());
     return;
   }
 
diff --git a/src/transcoder/transcoder.cpp b/src/transcoder/transcoder.cpp
index 4fba732a6..e97d6c05b 100644
--- a/src/transcoder/transcoder.cpp
+++ b/src/transcoder/transcoder.cpp
@@ -490,7 +490,7 @@ bool Transcoder::event(QEvent *e) {
     gst_bus_set_sync_handler(gst_pipeline_get_bus(GST_PIPELINE(finished_event->state_->pipeline_)), nullptr, nullptr, nullptr);
 
     // Remove it from the list - this will also destroy the GStreamer pipeline
-    current_jobs_.erase(it);  // clazy:exclude=strict-iterators
+    current_jobs_.erase(it);
 
     // Emit the finished signal
     emit JobComplete(input, output, finished_event->success_);
@@ -525,7 +525,7 @@ void Transcoder::Cancel() {
     }
 
     // Remove the job, this destroys the GStreamer pipeline too
-    it = current_jobs_.erase(it);  // clazy:exclude=strict-iterators
+    it = current_jobs_.erase(it);
   }
 
 }
diff --git a/src/widgets/fancytabwidget.cpp b/src/widgets/fancytabwidget.cpp
index 29a064104..7682e8ea9 100644
--- a/src/widgets/fancytabwidget.cpp
+++ b/src/widgets/fancytabwidget.cpp
@@ -278,7 +278,8 @@ void FancyTabWidget::CurrentTabChangedSlot(const int idx) {
 int FancyTabWidget::IndexOfTab(QWidget *widget) {
 
   if (!tabs_.contains(widget)) return -1;
-  return QTabWidget::indexOf(tabs_[widget]->page());
+  QWidget *page = tabs_.value(widget)->page();
+  return QTabWidget::indexOf(page);
 
 }
 
diff --git a/src/widgets/loginstatewidget.cpp b/src/widgets/loginstatewidget.cpp
index eca96fc5a..75acc3a42 100644
--- a/src/widgets/loginstatewidget.cpp
+++ b/src/widgets/loginstatewidget.cpp
@@ -101,7 +101,7 @@ void LoginStateWidget::SetLoggedIn(const State state, const QString &account_nam
 void LoginStateWidget::FocusLastCredentialField() {
 
   if (!credential_fields_.isEmpty()) {
-    QObject *object = credential_fields_.last();
+    QObject *object = credential_fields_.constLast();
     QWidget *widget = qobject_cast<QWidget*>(object);
     QLineEdit *line_edit = qobject_cast<QLineEdit*>(object);
 
diff --git a/src/widgets/stretchheaderview.cpp b/src/widgets/stretchheaderview.cpp
index aa3a2de85..adb6d0916 100644
--- a/src/widgets/stretchheaderview.cpp
+++ b/src/widgets/stretchheaderview.cpp
@@ -239,7 +239,7 @@ void StretchHeaderView::NormaliseWidths(const QList<int> &sections) {
     selected_sum = 0.0;
     for (int i = 0; i < count(); ++i) {
       if (sections.contains(i)) {
-        selected_sum += column_widths_[i];
+        selected_sum += column_widths_.value(i);
       }
     }
   }
@@ -263,7 +263,7 @@ void StretchHeaderView::ResizeSections(const QList<int> &sections) {
     if (isSectionHidden(i) || (!sections.isEmpty() && !sections.contains(i))) {
       continue;
     }
-    const int pixels = static_cast<int>(column_widths_[i] * width());
+    const int pixels = static_cast<int>(column_widths_.value(i) * width());
     if (pixels != 0) {
       resizeSection(i, pixels);
     }
diff --git a/src/widgets/volumeslider.cpp b/src/widgets/volumeslider.cpp
index 3d9775906..4ba9b87f4 100644
--- a/src/widgets/volumeslider.cpp
+++ b/src/widgets/volumeslider.cpp
@@ -118,7 +118,7 @@ void VolumeSlider::paintEvent(QPaintEvent*) {
 
   p.drawPixmap(0, 0, pixmap_gradient_, 0, 0, offset + padding, 0);
   p.drawPixmap(0, 0, pixmap_inset_);
-  p.drawPixmap(offset - handle_pixmaps_[0].width() / 2 + padding, 0, handle_pixmaps_[anim_count_]);
+  p.drawPixmap(offset - handle_pixmaps_.value(0).width() / 2 + padding, 0, handle_pixmaps_[anim_count_]);
 
   // Draw percentage number
   QStyleOptionViewItem opt;