diff --git a/libtransmission/.clang-tidy b/libtransmission/.clang-tidy
index 7b0ead67d..0c8c212e9 100644
--- a/libtransmission/.clang-tidy
+++ b/libtransmission/.clang-tidy
@@ -8,14 +8,10 @@ Checks: >
   -bugprone-narrowing-conversions,
   cert-*,
   -cert-err58-cpp,
-  clang-analyzer-core.*,
-  clang-analyzer-cplusplus.*,
-  clang-analyzer-deadcode.*,
-  clang-analyzer-nullability.*,
-  clang-analyzer-optin.cplusplus.*,
-  clang-analyzer-security.*,
-  clang-analyzer-valist.*,
+  clang-analyzer-*,
+  cppcoreguidelines-avoid-const-or-ref-data-members,
   cppcoreguidelines-init-variables,
+  cppcoreguidelines-interfaces-global-init,
   cppcoreguidelines-prefer-member-initializer,
   cppcoreguidelines-slicing,
   cppcoreguidelines-special-member-functions,
diff --git a/libtransmission/file-posix.cc b/libtransmission/file-posix.cc
index 88b2d153c..68fafb239 100644
--- a/libtransmission/file-posix.cc
+++ b/libtransmission/file-posix.cc
@@ -781,7 +781,7 @@ bool tr_sys_file_flush(tr_sys_file_t handle, tr_error** error)
 {
     TR_ASSERT(handle != TR_BAD_SYS_FILE);
 
-    bool const ret = (isatty(handle) ? true : (fsync(handle) != -1));
+    bool const ret = (isatty(handle) != 0) || (fsync(handle) != -1);
 
     if (!ret)
     {
diff --git a/qt/.clang-tidy b/qt/.clang-tidy
index bb0b7af3c..867a46fcd 100644
--- a/qt/.clang-tidy
+++ b/qt/.clang-tidy
@@ -6,35 +6,22 @@ Checks: >
   -bugprone-branch-clone,
   -bugprone-easily-swappable-parameters,
   -bugprone-narrowing-conversions,
-  -bugprone-unchecked-optional-access,
   cert-*,
-  clang-analyzer-optin*,
-  -clang-diagnostic-c++98*,
-  -clang-diagnostic-double-promotion,
-  -clang-diagnostic-exit-time-destructors,
-  -clang-diagnostic-global-constructors,
-  -clang-diagnostic-shorten-64-to-32,
-  -clang-diagnostic-sign-compare,
-  -clang-diagnostic-sign-conversion,
+  clang-analyzer-*,
   cppcoreguidelines-*,
   -cppcoreguidelines-avoid-magic-numbers,
   -cppcoreguidelines-macro-usage,
   -cppcoreguidelines-narrowing-conversions,
   -cppcoreguidelines-non-private-member-variables-in-classes,
   -cppcoreguidelines-owning-memory,
-  -cppcoreguidelines-prefer-member-initializer,
-  -cppcoreguidelines-pro-bounds-array-to-pointer-decay,
   -cppcoreguidelines-pro-bounds-constant-array-index,
   -cppcoreguidelines-pro-bounds-pointer-arithmetic,
   -cppcoreguidelines-pro-type-const-cast,
   google-readability-*,
-  -google-readability-casting,
   google-runtime-operator,
   hicpp-*,
   -hicpp-multiway-paths-covered,
-  -hicpp-no-array-decay,
   -hicpp-signed-bitwise,
-  -hicpp-special-member-functions,
   misc-*,
   -misc-no-recursion,
   -misc-non-private-member-variables-in-classes,
@@ -46,9 +33,8 @@ Checks: >
   -readability-function-cognitive-complexity,
   -readability-identifier-length,
   -readability-implicit-bool-conversion,
-  -readability-inconsistent-declaration-parameter-name,
   -readability-magic-numbers,
-  -readability-redundant-access-specifiers
+  -readability-redundant-access-specifiers, # keep: 'private' vs 'private slots'
 
 CheckOptions:
   - { key: readability-identifier-naming.ClassCase,                value: CamelCase  }
diff --git a/qt/AddData.cc b/qt/AddData.cc
index 7c1caf851..34f25384d 100644
--- a/qt/AddData.cc
+++ b/qt/AddData.cc
@@ -22,7 +22,7 @@ namespace
 QString getNameFromMetainfo(QByteArray const& benc)
 {
     auto metainfo = tr_torrent_metainfo{};
-    if (!metainfo.parseBenc({ benc.constData(), size_t(benc.size()) }))
+    if (!metainfo.parseBenc({ benc.constData(), static_cast<size_t>(benc.size()) }))
     {
         return {};
     }
diff --git a/qt/Application.cc b/qt/Application.cc
index ef1b39e60..704c1e7c2 100644
--- a/qt/Application.cc
+++ b/qt/Application.cc
@@ -405,16 +405,16 @@ void Application::quitLater() const
     QTimer::singleShot(0, this, SLOT(quit()));
 }
 
-void Application::onTorrentsEdited(torrent_ids_t const& ids) const
+void Application::onTorrentsEdited(torrent_ids_t const& torrent_ids) const
 {
     // the backend's tr_info has changed, so reload those fields
-    session_->initTorrents(ids);
+    session_->initTorrents(torrent_ids);
 }
 
-QStringList Application::getNames(torrent_ids_t const& ids) const
+QStringList Application::getNames(torrent_ids_t const& torrent_ids) const
 {
     QStringList names;
-    for (auto const& id : ids)
+    for (auto const& id : torrent_ids)
     {
         names.push_back(model_->getTorrentFromId(id)->name());
     }
@@ -423,23 +423,25 @@ QStringList Application::getNames(torrent_ids_t const& ids) const
     return names;
 }
 
-void Application::onTorrentsAdded(torrent_ids_t const& ids) const
+void Application::onTorrentsAdded(torrent_ids_t const& torrent_ids) const
 {
-    if (prefs_->getBool(Prefs::SHOW_NOTIFICATION_ON_ADD))
+    if (!prefs_->getBool(Prefs::SHOW_NOTIFICATION_ON_ADD))
     {
-        for (auto id : ids)
-        {
-            notifyTorrentAdded(model_->getTorrentFromId(id));
-        }
+        return;
+    }
+
+    for (auto id : torrent_ids)
+    {
+        notifyTorrentAdded(model_->getTorrentFromId(id));
     }
 }
 
-void Application::onTorrentsCompleted(torrent_ids_t const& ids) const
+void Application::onTorrentsCompleted(torrent_ids_t const& torrent_ids) const
 {
     if (prefs_->getBool(Prefs::SHOW_NOTIFICATION_ON_COMPLETE))
     {
-        auto const title = tr("Torrent Completed", nullptr, static_cast<int>(ids.size()));
-        auto const body = getNames(ids).join(QStringLiteral("\n"));
+        auto const title = tr("Torrent Completed", nullptr, static_cast<int>(std::size(torrent_ids)));
+        auto const body = getNames(torrent_ids).join(QStringLiteral("\n"));
         notifyApp(title, body);
     }
 
@@ -455,11 +457,11 @@ void Application::onTorrentsCompleted(torrent_ids_t const& ids) const
     }
 }
 
-void Application::onTorrentsNeedInfo(torrent_ids_t const& ids) const
+void Application::onTorrentsNeedInfo(torrent_ids_t const& torrent_ids) const
 {
-    if (!ids.empty())
+    if (!torrent_ids.empty())
     {
-        session_->initTorrents(ids);
+        session_->initTorrents(torrent_ids);
     }
 }
 
diff --git a/qt/Application.h b/qt/Application.h
index 67b2481f5..e0d475027 100644
--- a/qt/Application.h
+++ b/qt/Application.h
@@ -54,10 +54,10 @@ public slots:
 private slots:
     void consentGiven(int result) const;
     void onSessionSourceChanged() const;
-    void onTorrentsAdded(torrent_ids_t const& torrents) const;
-    void onTorrentsCompleted(torrent_ids_t const& torrents) const;
-    void onTorrentsEdited(torrent_ids_t const& torrents) const;
-    void onTorrentsNeedInfo(torrent_ids_t const& torrents) const;
+    void onTorrentsAdded(torrent_ids_t const& torrent_ids) const;
+    void onTorrentsCompleted(torrent_ids_t const& torrent_ids) const;
+    void onTorrentsEdited(torrent_ids_t const& torrent_ids) const;
+    void onTorrentsNeedInfo(torrent_ids_t const& torrent_ids) const;
     void refreshPref(int key) const;
     void refreshTorrents();
     void saveGeometry() const;
diff --git a/qt/DetailsDialog.cc b/qt/DetailsDialog.cc
index b01c50058..3e93ef726 100644
--- a/qt/DetailsDialog.cc
+++ b/qt/DetailsDialog.cc
@@ -71,7 +71,7 @@ public:
     }
 
 signals:
-    void trackerListEdited(QString trackerList);
+    void trackerListEdited(QString /*tracker_list*/);
 
 private slots:
     void onButtonBoxClicked(QAbstractButton* button)
@@ -664,7 +664,7 @@ void DetailsDialog::refreshUI()
         }
         else
         {
-            auto const seconds = int(std::difftime(now, baseline));
+            auto const seconds = static_cast<int>(std::difftime(now, baseline));
             string = fmt.timeToString(seconds);
         }
     }
@@ -725,7 +725,7 @@ void DetailsDialog::refreshUI()
             }
         }
 
-        auto const seconds = int(std::difftime(now, latest));
+        auto const seconds = static_cast<int>(std::difftime(now, latest));
 
         if (seconds < 0)
         {
@@ -1037,8 +1037,8 @@ void DetailsDialog::refreshUI()
 
         setIfIdle(ui_.bandwidthPriorityCombo, i);
 
-        setIfIdle(ui_.singleDownSpin, int(baseline.downloadLimit().getKBps()));
-        setIfIdle(ui_.singleUpSpin, int(baseline.uploadLimit().getKBps()));
+        setIfIdle(ui_.singleDownSpin, static_cast<int>(baseline.downloadLimit().getKBps()));
+        setIfIdle(ui_.singleUpSpin, static_cast<int>(baseline.uploadLimit().getKBps()));
         setIfIdle(ui_.peerLimitSpin, baseline.peerLimit());
     }
 
@@ -1198,7 +1198,9 @@ void DetailsDialog::refreshUI()
 
             item->setText(COL_UP, peer.rate_to_peer.isZero() ? QString() : fmt.speedToString(peer.rate_to_peer));
             item->setText(COL_DOWN, peer.rate_to_client.isZero() ? QString() : fmt.speedToString(peer.rate_to_client));
-            item->setText(COL_PERCENT, peer.progress > 0 ? QStringLiteral("%1%").arg(int(peer.progress * 100.0)) : QString());
+            item->setText(
+                COL_PERCENT,
+                peer.progress > 0 ? QStringLiteral("%1%").arg(static_cast<int>(peer.progress * 100.0)) : QString());
             item->setText(COL_STATUS, code);
             item->setToolTip(COL_STATUS, code_tip);
 
@@ -1572,9 +1574,9 @@ void DetailsDialog::onFileWantedChanged(QSet<int> const& indices, bool wanted)
     torrentSet(key, indices.values());
 }
 
-void DetailsDialog::onPathEdited(QString const& oldpath, QString const& newname)
+void DetailsDialog::onPathEdited(QString const& old_path, QString const& new_name)
 {
-    session_.torrentRenamePath(ids_, oldpath, newname);
+    session_.torrentRenamePath(ids_, old_path, new_name);
 }
 
 void DetailsDialog::onOpenRequested(QString const& path) const
diff --git a/qt/FileTreeDelegate.cc b/qt/FileTreeDelegate.cc
index 6174db162..94182f2b7 100644
--- a/qt/FileTreeDelegate.cc
+++ b/qt/FileTreeDelegate.cc
@@ -56,7 +56,7 @@ void FileTreeDelegate::paint(QPainter* painter, QStyleOptionViewItem const& opti
         p.maximum = 100;
         p.textAlignment = Qt::AlignCenter;
         p.textVisible = true;
-        p.progress = int(100.0 * index.data().toDouble());
+        p.progress = static_cast<int>(100.0 * index.data().toDouble());
         p.text = QStringLiteral("%1%").arg(p.progress);
         style->drawControl(QStyle::CE_ProgressBar, &p, painter);
     }
diff --git a/qt/FileTreeItem.cc b/qt/FileTreeItem.cc
index b5eea8a3a..82affff39 100644
--- a/qt/FileTreeItem.cc
+++ b/qt/FileTreeItem.cc
@@ -337,11 +337,11 @@ int FileTreeItem::priority() const
     return i;
 }
 
-void FileTreeItem::setSubtreePriority(int i, QSet<int>& ids)
+void FileTreeItem::setSubtreePriority(int priority, QSet<int>& ids)
 {
-    if (priority_ != i)
+    if (priority_ != priority)
     {
-        priority_ = i;
+        priority_ = priority;
 
         if (file_index_ >= 0)
         {
@@ -351,7 +351,7 @@ void FileTreeItem::setSubtreePriority(int i, QSet<int>& ids)
 
     for (FileTreeItem* const child : children_)
     {
-        child->setSubtreePriority(i, ids);
+        child->setSubtreePriority(priority, ids);
     }
 }
 
diff --git a/qt/FileTreeModel.cc b/qt/FileTreeModel.cc
index 787bb5405..f7433e2e8 100644
--- a/qt/FileTreeModel.cc
+++ b/qt/FileTreeModel.cc
@@ -173,13 +173,13 @@ Qt::ItemFlags FileTreeModel::flags(QModelIndex const& index) const
     return { i };
 }
 
-bool FileTreeModel::setData(QModelIndex const& index, QVariant const& newname, int role)
+bool FileTreeModel::setData(QModelIndex const& index, QVariant const& value, int role)
 {
     if (role == Qt::EditRole)
     {
         FileTreeItem const* item = itemFromIndex(index);
 
-        emit pathEdited(item->path(), newname.toString());
+        emit pathEdited(item->path(), value.toString());
     }
 
     return false; // don't update the view until the session confirms the change
diff --git a/qt/FileTreeModel.h b/qt/FileTreeModel.h
index a7077935a..8fdad1a02 100644
--- a/qt/FileTreeModel.h
+++ b/qt/FileTreeModel.h
@@ -54,7 +54,7 @@ public:
         int priority,
         uint64_t size,
         uint64_t have,
-        bool torrent_changed);
+        bool update_fields);
 
     bool openFile(QModelIndex const& index);
 
@@ -69,7 +69,7 @@ public:
     // QAbstractItemModel
     QVariant data(QModelIndex const& index, int role = Qt::DisplayRole) const override;
     Qt::ItemFlags flags(QModelIndex const& index) const override;
-    QVariant headerData(int section, Qt::Orientation orientation, int role = Qt::DisplayRole) const override;
+    QVariant headerData(int column, Qt::Orientation orientation, int role = Qt::DisplayRole) const override;
     QModelIndex index(int row, int column, QModelIndex const& parent = {}) const override;
     QModelIndex parent(QModelIndex const& child) const override;
     int rowCount(QModelIndex const& parent = {}) const override;
diff --git a/qt/FileTreeView.h b/qt/FileTreeView.h
index e8cc68dc2..c37d4d0e5 100644
--- a/qt/FileTreeView.h
+++ b/qt/FileTreeView.h
@@ -28,7 +28,7 @@ public:
     FileTreeView(QWidget* parent = nullptr, bool editable = true);
 
     void clear();
-    void update(FileList const& files, bool update_properties = true);
+    void update(FileList const& files, bool update_fields = true);
 
     void setEditable(bool editable);
 
diff --git a/qt/FilterBar.cc b/qt/FilterBar.cc
index 05ed7488f..3408be8aa 100644
--- a/qt/FilterBar.cc
+++ b/qt/FilterBar.cc
@@ -99,7 +99,7 @@ QString getCountString(size_t n)
 }
 
 Torrent::fields_t constexpr TrackerFields = {
-    uint64_t(1) << Torrent::TRACKER_STATS,
+    static_cast<uint64_t>(1) << Torrent::TRACKER_STATS,
 };
 
 auto constexpr ActivityFields = FilterMode::TorrentFields;
@@ -127,7 +127,7 @@ void FilterBar::refreshTrackers()
     // update the "All" row
     auto const num_trackers = torrents_per_sitename.size();
     auto* item = tracker_model_->item(ROW_TOTALS);
-    item->setData(int(num_trackers), FilterBarComboBox::CountRole);
+    item->setData(static_cast<int>(num_trackers), FilterBarComboBox::CountRole);
     item->setData(getCountString(num_trackers), FilterBarComboBox::CountStringRole);
 
     auto update_tracker_item = [](QStandardItem* i, auto const& it)
@@ -140,7 +140,7 @@ void FilterBar::refreshTrackers()
         i->setData(display_name, TRACKER_ROLE);
         i->setData(getCountString(static_cast<size_t>(count)), FilterBarComboBox::CountStringRole);
         i->setData(icon, Qt::DecorationRole);
-        i->setData(int(count), FilterBarComboBox::CountRole);
+        i->setData(static_cast<int>(count), FilterBarComboBox::CountRole);
 
         return i;
     };
@@ -221,16 +221,13 @@ FilterBar::FilterBar(Prefs& prefs, TorrentModel const& torrents, TorrentFilter c
     count_label_ = new QLabel(tr("Show:"), this);
     h->addWidget(count_label_);
 
-    activity_combo_ = createActivityCombo();
     h->addWidget(activity_combo_);
 
-    tracker_model_ = new QStandardItemModel(this);
     tracker_combo_ = createTrackerCombo(tracker_model_);
     h->addWidget(tracker_combo_);
 
     h->addStretch();
 
-    line_edit_ = new QLineEdit(this);
     line_edit_->setClearButtonEnabled(true);
     line_edit_->setPlaceholderText(tr("Search..."));
     line_edit_->setMaximumWidth(250);
@@ -249,7 +246,7 @@ FilterBar::FilterBar(Prefs& prefs, TorrentModel const& torrents, TorrentFilter c
     connect(&trApp->faviconCache(), &FaviconCache::pixmapReady, this, &FilterBar::recountTrackersSoon);
 
     recountAllSoon();
-    is_bootstrapping_ = false;
+    is_bootstrapping_ = false; // NOLINT cppcoreguidelines-prefer-member-initializer
 
     // initialize our state
     for (int const key : { Prefs::FILTER_MODE, Prefs::FILTER_TRACKERS })
@@ -354,9 +351,9 @@ void FilterBar::onActivityIndexChanged(int i)
 ****
 ***/
 
-void FilterBar::recountSoon(Pending const& pending)
+void FilterBar::recountSoon(Pending const& fields)
 {
-    pending_ |= pending;
+    pending_ |= fields;
 
     if (!recount_timer_.isActive())
     {
diff --git a/qt/FilterBar.h b/qt/FilterBar.h
index 9e29c6860..241602309 100644
--- a/qt/FilterBar.h
+++ b/qt/FilterBar.h
@@ -8,6 +8,8 @@
 #include <bitset>
 #include <map>
 
+#include <QLineEdit>
+#include <QStandardItemModel>
 #include <QTimer>
 #include <QWidget>
 
@@ -18,8 +20,6 @@
 #include "Typedefs.h"
 
 class QLabel;
-class QLineEdit;
-class QStandardItemModel;
 class QString;
 
 class FilterBarComboBox;
@@ -58,12 +58,12 @@ private:
     TorrentFilter const& filter_;
 
     std::map<QString, int> sitename_counts_;
-    FilterBarComboBox* activity_combo_ = {};
+    FilterBarComboBox* const activity_combo_ = createActivityCombo();
     FilterBarComboBox* tracker_combo_ = {};
     QLabel* count_label_ = {};
-    QStandardItemModel* tracker_model_ = {};
+    QStandardItemModel* const tracker_model_ = new QStandardItemModel{ this };
     QTimer recount_timer_;
-    QLineEdit* line_edit_ = {};
+    QLineEdit* const line_edit_ = new QLineEdit{ this };
     Pending pending_ = {};
     bool is_bootstrapping_ = {};
 
diff --git a/qt/FreeSpaceLabel.h b/qt/FreeSpaceLabel.h
index 7c175d240..e435f32b6 100644
--- a/qt/FreeSpaceLabel.h
+++ b/qt/FreeSpaceLabel.h
@@ -27,7 +27,7 @@ public:
     explicit FreeSpaceLabel(QWidget* parent = nullptr);
 
     void setSession(Session& session);
-    void setPath(QString const& folder);
+    void setPath(QString const& path);
 
 private slots:
     void onTimer();
diff --git a/qt/MainWindow.h b/qt/MainWindow.h
index df84a840a..b079564a0 100644
--- a/qt/MainWindow.h
+++ b/qt/MainWindow.h
@@ -125,7 +125,7 @@ private slots:
 private:
     QIcon addEmblem(QIcon icon, QStringList const& emblem_names) const;
 
-    torrent_ids_t getSelectedTorrents(bool withMetadataOnly = false) const;
+    torrent_ids_t getSelectedTorrents(bool with_metadata_only = false) const;
     void updateNetworkIcon();
 
     QMenu* createOptionsMenu();
diff --git a/qt/PrefsDialog.h b/qt/PrefsDialog.h
index 042a10e6b..da907316a 100644
--- a/qt/PrefsDialog.h
+++ b/qt/PrefsDialog.h
@@ -29,7 +29,7 @@ public:
     PrefsDialog(Session&, Prefs&, QWidget* parent = nullptr);
 
 private slots:
-    void focusChanged(QWidget* old, QWidget* now);
+    void focusChanged(QWidget* old, QWidget* cur);
     void checkBoxToggled(bool checked);
     void spinBoxEditingFinished();
     void timeEditingFinished();
diff --git a/qt/RpcClient.cc b/qt/RpcClient.cc
index 81fa6f39f..9de81b160 100644
--- a/qt/RpcClient.cc
+++ b/qt/RpcClient.cc
@@ -283,23 +283,23 @@ void RpcClient::localRequestFinished(TrVariantPtr response)
     promise.reportFinished(&result);
 }
 
-int64_t RpcClient::parseResponseTag(tr_variant& json) const
+int64_t RpcClient::parseResponseTag(tr_variant& response) const
 {
-    auto const tag = dictFind<int>(&json, TR_KEY_tag);
+    auto const tag = dictFind<int>(&response, TR_KEY_tag);
     return tag ? *tag : -1;
 }
 
-RpcResponse RpcClient::parseResponseData(tr_variant& json) const
+RpcResponse RpcClient::parseResponseData(tr_variant& response) const
 {
     RpcResponse ret;
 
-    if (auto const result = dictFind<QString>(&json, TR_KEY_result); result)
+    if (auto const result = dictFind<QString>(&response, TR_KEY_result); result)
     {
         ret.result = *result;
         ret.success = *result == QStringLiteral("success");
     }
 
-    if (tr_variant* args = nullptr; tr_variantDictFindDict(&json, TR_KEY_arguments, &args))
+    if (tr_variant* args = nullptr; tr_variantDictFindDict(&response, TR_KEY_arguments, &args))
     {
         ret.args = createVariant();
         *ret.args = *args;
diff --git a/qt/Session.cc b/qt/Session.cc
index 9db5abc25..3d1950578 100644
--- a/qt/Session.cc
+++ b/qt/Session.cc
@@ -288,10 +288,6 @@ Session::Session(QString config_dir, Prefs& prefs)
     : config_dir_(std::move(config_dir))
     , prefs_(prefs)
 {
-    stats_ = {};
-    stats_.ratio = TR_RATIO_NA;
-    cumulative_stats_ = stats_;
-
     connect(&prefs_, &Prefs::changed, this, &Session::updatePref);
     connect(&rpc_, &RpcClient::httpAuthenticationRequired, this, &Session::httpAuthenticationRequired);
     connect(&rpc_, &RpcClient::dataReadProgress, this, &Session::dataReadProgress);
@@ -383,17 +379,17 @@ bool Session::isLocal() const
 ****
 ***/
 
-void Session::addOptionalIds(tr_variant* args, torrent_ids_t const& ids) const
+void Session::addOptionalIds(tr_variant* args_dict, torrent_ids_t const& torrent_ids) const
 {
     auto constexpr RecentlyActiveKey = std::string_view{ "recently-active" };
 
-    if (&ids == &RecentlyActiveIDs)
+    if (&torrent_ids == &RecentlyActiveIDs)
     {
-        dictAdd(args, TR_KEY_ids, RecentlyActiveKey);
+        dictAdd(args_dict, TR_KEY_ids, RecentlyActiveKey);
     }
-    else if (!ids.empty())
+    else if (!std::empty(torrent_ids))
     {
-        dictAdd(args, TR_KEY_ids, ids);
+        dictAdd(args_dict, TR_KEY_ids, torrent_ids);
     }
 }
 
@@ -410,76 +406,76 @@ Session::Tag Session::torrentSetImpl(tr_variant* args)
     return tag;
 }
 
-Session::Tag Session::torrentSet(torrent_ids_t const& ids, tr_quark const key, double value)
+Session::Tag Session::torrentSet(torrent_ids_t const& torrent_ids, tr_quark const key, double value)
 {
     tr_variant args;
     tr_variantInitDict(&args, 2);
-    addOptionalIds(&args, ids);
+    addOptionalIds(&args, torrent_ids);
     dictAdd(&args, key, value);
     return torrentSetImpl(&args);
 }
 
-Session::Tag Session::torrentSet(torrent_ids_t const& ids, tr_quark const key, int value)
+Session::Tag Session::torrentSet(torrent_ids_t const& torrent_ids, tr_quark const key, int value)
 {
     tr_variant args;
     tr_variantInitDict(&args, 2);
-    addOptionalIds(&args, ids);
+    addOptionalIds(&args, torrent_ids);
     dictAdd(&args, key, value);
     return torrentSetImpl(&args);
 }
 
-Session::Tag Session::torrentSet(torrent_ids_t const& ids, tr_quark const key, bool value)
+Session::Tag Session::torrentSet(torrent_ids_t const& torrent_ids, tr_quark const key, bool value)
 {
     tr_variant args;
     tr_variantInitDict(&args, 2);
-    addOptionalIds(&args, ids);
+    addOptionalIds(&args, torrent_ids);
     dictAdd(&args, key, value);
     return torrentSetImpl(&args);
 }
 
-Session::Tag Session::torrentSet(torrent_ids_t const& ids, tr_quark const key, QString const& value)
+Session::Tag Session::torrentSet(torrent_ids_t const& torrent_ids, tr_quark const key, QString const& value)
 {
     tr_variant args;
     tr_variantInitDict(&args, 2);
-    addOptionalIds(&args, ids);
+    addOptionalIds(&args, torrent_ids);
     dictAdd(&args, key, value);
     return torrentSetImpl(&args);
 }
 
-Session::Tag Session::torrentSet(torrent_ids_t const& ids, tr_quark const key, QStringList const& value)
+Session::Tag Session::torrentSet(torrent_ids_t const& torrent_ids, tr_quark const key, QStringList const& value)
 {
     tr_variant args;
     tr_variantInitDict(&args, 2);
-    addOptionalIds(&args, ids);
+    addOptionalIds(&args, torrent_ids);
     dictAdd(&args, key, value);
     return torrentSetImpl(&args);
 }
 
-Session::Tag Session::torrentSet(torrent_ids_t const& ids, tr_quark const key, QList<int> const& value)
+Session::Tag Session::torrentSet(torrent_ids_t const& torrent_ids, tr_quark const key, QList<int> const& value)
 {
     tr_variant args;
     tr_variantInitDict(&args, 2);
-    addOptionalIds(&args, ids);
+    addOptionalIds(&args, torrent_ids);
     dictAdd(&args, key, value);
     return torrentSetImpl(&args);
 }
 
-void Session::torrentSetLocation(torrent_ids_t const& ids, QString const& location, bool do_move)
+void Session::torrentSetLocation(torrent_ids_t const& torrent_ids, QString const& path, bool do_move)
 {
     tr_variant args;
     tr_variantInitDict(&args, 3);
-    addOptionalIds(&args, ids);
-    dictAdd(&args, TR_KEY_location, location);
+    addOptionalIds(&args, torrent_ids);
+    dictAdd(&args, TR_KEY_location, path);
     dictAdd(&args, TR_KEY_move, do_move);
 
     exec(TR_KEY_torrent_set_location, &args);
 }
 
-void Session::torrentRenamePath(torrent_ids_t const& ids, QString const& oldpath, QString const& newname)
+void Session::torrentRenamePath(torrent_ids_t const& torrent_ids, QString const& oldpath, QString const& newname)
 {
     tr_variant args;
     tr_variantInitDict(&args, 2);
-    addOptionalIds(&args, ids);
+    addOptionalIds(&args, torrent_ids);
     dictAdd(&args, TR_KEY_path, oldpath);
     dictAdd(&args, TR_KEY_name, newname);
 
@@ -507,7 +503,7 @@ void Session::torrentRenamePath(torrent_ids_t const& ids, QString const& oldpath
             d->show();
         });
 
-    q->add([this, ids](RpcResponse const& /*r*/) { refreshTorrents(ids, TorrentProperties::Rename); });
+    q->add([this, torrent_ids](RpcResponse const& /*r*/) { refreshTorrents(torrent_ids, TorrentProperties::Rename); });
 
     q->run();
 }
@@ -645,7 +641,7 @@ std::vector<std::string_view> const& Session::getKeyNames(TorrentProperties prop
     return names;
 }
 
-void Session::refreshTorrents(torrent_ids_t const& ids, TorrentProperties props)
+void Session::refreshTorrents(torrent_ids_t const& torrent_ids, TorrentProperties props)
 {
     auto constexpr Table = std::string_view{ "table" };
 
@@ -653,13 +649,13 @@ void Session::refreshTorrents(torrent_ids_t const& ids, TorrentProperties props)
     tr_variantInitDict(&args, 3);
     dictAdd(&args, TR_KEY_format, Table);
     dictAdd(&args, TR_KEY_fields, getKeyNames(props));
-    addOptionalIds(&args, ids);
+    addOptionalIds(&args, torrent_ids);
 
     auto* q = new RpcQueue();
 
     q->add([this, &args]() { return exec(TR_KEY_torrent_get, &args); });
 
-    bool const all_torrents = ids.empty();
+    bool const all_torrents = std::empty(torrent_ids);
 
     q->add(
         [this, all_torrents](RpcResponse const& r)
@@ -690,17 +686,17 @@ void Session::refreshExtraStats(torrent_ids_t const& ids)
     refreshTorrents(ids, TorrentProperties::DetailStat);
 }
 
-void Session::sendTorrentRequest(std::string_view request, torrent_ids_t const& ids)
+void Session::sendTorrentRequest(std::string_view request, torrent_ids_t const& torrent_ids)
 {
     tr_variant args;
     tr_variantInitDict(&args, 1);
-    addOptionalIds(&args, ids);
+    addOptionalIds(&args, torrent_ids);
 
     auto* q = new RpcQueue();
 
     q->add([this, request, &args]() { return exec(request, &args); });
 
-    q->add([this, ids]() { refreshTorrents(ids, TorrentProperties::MainStats); });
+    q->add([this, torrent_ids]() { refreshTorrents(torrent_ids, TorrentProperties::MainStats); });
 
     q->run();
 }
@@ -812,29 +808,29 @@ RpcResponseFuture Session::exec(std::string_view method, tr_variant* args)
     return rpc_.exec(method, args);
 }
 
-void Session::updateStats(tr_variant* d, tr_session_stats* stats)
+void Session::updateStats(tr_variant* args_dict, tr_session_stats* stats)
 {
-    if (auto const value = dictFind<uint64_t>(d, TR_KEY_uploadedBytes); value)
+    if (auto const value = dictFind<uint64_t>(args_dict, TR_KEY_uploadedBytes); value)
     {
         stats->uploadedBytes = *value;
     }
 
-    if (auto const value = dictFind<uint64_t>(d, TR_KEY_downloadedBytes); value)
+    if (auto const value = dictFind<uint64_t>(args_dict, TR_KEY_downloadedBytes); value)
     {
         stats->downloadedBytes = *value;
     }
 
-    if (auto const value = dictFind<uint64_t>(d, TR_KEY_filesAdded); value)
+    if (auto const value = dictFind<uint64_t>(args_dict, TR_KEY_filesAdded); value)
     {
         stats->filesAdded = *value;
     }
 
-    if (auto const value = dictFind<uint64_t>(d, TR_KEY_sessionCount); value)
+    if (auto const value = dictFind<uint64_t>(args_dict, TR_KEY_sessionCount); value)
     {
         stats->sessionCount = *value;
     }
 
-    if (auto const value = dictFind<uint64_t>(d, TR_KEY_secondsActive); value)
+    if (auto const value = dictFind<uint64_t>(args_dict, TR_KEY_secondsActive); value)
     {
         stats->secondsActive = *value;
     }
@@ -857,13 +853,13 @@ void Session::updateStats(tr_variant* dict)
     emit statsUpdated();
 }
 
-void Session::updateInfo(tr_variant* d)
+void Session::updateInfo(tr_variant* args_dict)
 {
     disconnect(&prefs_, &Prefs::changed, this, &Session::updatePref);
 
     for (int i = Prefs::FIRST_CORE_PREF; i <= Prefs::LAST_CORE_PREF; ++i)
     {
-        tr_variant const* b(tr_variantDictFind(d, prefs_.getKey(i)));
+        tr_variant const* b(tr_variantDictFind(args_dict, prefs_.getKey(i)));
 
         if (b == nullptr)
         {
@@ -932,12 +928,12 @@ void Session::updateInfo(tr_variant* d)
         }
     }
 
-    if (auto const b = dictFind<bool>(d, TR_KEY_seedRatioLimited); b)
+    if (auto const b = dictFind<bool>(args_dict, TR_KEY_seedRatioLimited); b)
     {
         prefs_.set(Prefs::RATIO_ENABLED, *b);
     }
 
-    if (auto const x = dictFind<double>(d, TR_KEY_seedRatioLimit); x)
+    if (auto const x = dictFind<double>(args_dict, TR_KEY_seedRatioLimit); x)
     {
         prefs_.set(Prefs::RATIO, *x);
     }
@@ -954,17 +950,17 @@ void Session::updateInfo(tr_variant* d)
         prefs_.set(Prefs::RPC_WHITELIST, QString::fromUtf8(tr_sessionGetRPCWhitelist(session_)));
     }
 
-    if (auto const size = dictFind<int>(d, TR_KEY_blocklist_size); size && *size != blocklistSize())
+    if (auto const size = dictFind<int>(args_dict, TR_KEY_blocklist_size); size && *size != blocklistSize())
     {
         setBlocklistSize(*size);
     }
 
-    if (auto const str = dictFind<QString>(d, TR_KEY_version); str)
+    if (auto const str = dictFind<QString>(args_dict, TR_KEY_version); str)
     {
         session_version_ = *str;
     }
 
-    if (auto const str = dictFind<QString>(d, TR_KEY_session_id); str)
+    if (auto const str = dictFind<QString>(args_dict, TR_KEY_session_id); str)
     {
         session_id_ = *str;
         is_definitely_local_session_ = tr_session_id::isLocal(session_id_.toUtf8().constData());
@@ -986,30 +982,30 @@ void Session::setBlocklistSize(int64_t i)
     emit blocklistUpdated(i);
 }
 
-void Session::addTorrent(AddData add_me, tr_variant* args, bool trash_original)
+void Session::addTorrent(AddData add_me, tr_variant* args_dict, bool trash_original)
 {
-    assert(tr_variantDictFind(args, TR_KEY_filename) == nullptr);
-    assert(tr_variantDictFind(args, TR_KEY_metainfo) == nullptr);
+    assert(tr_variantDictFind(args_dict, TR_KEY_filename) == nullptr);
+    assert(tr_variantDictFind(args_dict, TR_KEY_metainfo) == nullptr);
 
-    if (tr_variantDictFind(args, TR_KEY_paused) == nullptr)
+    if (tr_variantDictFind(args_dict, TR_KEY_paused) == nullptr)
     {
-        dictAdd(args, TR_KEY_paused, !prefs_.getBool(Prefs::START));
+        dictAdd(args_dict, TR_KEY_paused, !prefs_.getBool(Prefs::START));
     }
 
     switch (add_me.type)
     {
     case AddData::MAGNET:
-        dictAdd(args, TR_KEY_filename, add_me.magnet);
+        dictAdd(args_dict, TR_KEY_filename, add_me.magnet);
         break;
 
     case AddData::URL:
-        dictAdd(args, TR_KEY_filename, add_me.url.toString());
+        dictAdd(args_dict, TR_KEY_filename, add_me.url.toString());
         break;
 
     case AddData::FILENAME:
         [[fallthrough]];
     case AddData::METAINFO:
-        dictAdd(args, TR_KEY_metainfo, add_me.toBase64());
+        dictAdd(args_dict, TR_KEY_metainfo, add_me.toBase64());
         break;
 
     default:
@@ -1020,7 +1016,7 @@ void Session::addTorrent(AddData add_me, tr_variant* args, bool trash_original)
     auto* q = new RpcQueue();
 
     q->add(
-        [this, args]() { return exec("torrent-add", args); },
+        [this, args_dict]() { return exec("torrent-add", args_dict); },
         [add_me](RpcResponse const& r)
         {
             auto* d = new QMessageBox(
diff --git a/qt/Session.h b/qt/Session.h
index cb4a50e68..edc4fdee7 100644
--- a/qt/Session.h
+++ b/qt/Session.h
@@ -84,27 +84,27 @@ public:
     RpcResponseFuture exec(std::string_view method, tr_variant* args);
 
     using Tag = RpcQueue::Tag;
-    Tag torrentSet(torrent_ids_t const& ids, tr_quark const key, bool val);
-    Tag torrentSet(torrent_ids_t const& ids, tr_quark const key, int val);
-    Tag torrentSet(torrent_ids_t const& ids, tr_quark const key, double val);
-    Tag torrentSet(torrent_ids_t const& ids, tr_quark const key, QString const& val);
-    Tag torrentSet(torrent_ids_t const& ids, tr_quark const key, QList<int> const& val);
-    Tag torrentSet(torrent_ids_t const& ids, tr_quark const key, QStringList const& val);
+    Tag torrentSet(torrent_ids_t const& torrent_ids, tr_quark const key, bool val);
+    Tag torrentSet(torrent_ids_t const& torrent_ids, tr_quark const key, int val);
+    Tag torrentSet(torrent_ids_t const& torrent_ids, tr_quark const key, double val);
+    Tag torrentSet(torrent_ids_t const& torrent_ids, tr_quark const key, QString const& val);
+    Tag torrentSet(torrent_ids_t const& torrent_ids, tr_quark const key, QList<int> const& val);
+    Tag torrentSet(torrent_ids_t const& torrent_ids, tr_quark const key, QStringList const& val);
 
-    void torrentSetLocation(torrent_ids_t const& ids, QString const& path, bool do_move);
-    void torrentRenamePath(torrent_ids_t const& ids, QString const& oldpath, QString const& newname);
-    void addTorrent(AddData addme, tr_variant* top, bool trash_original);
+    void torrentSetLocation(torrent_ids_t const& torrent_ids, QString const& path, bool do_move);
+    void torrentRenamePath(torrent_ids_t const& torrent_ids, QString const& oldpath, QString const& newname);
+    void addTorrent(AddData add_me, tr_variant* args_dict, bool trash_original);
     void initTorrents(torrent_ids_t const& ids = {});
-    void pauseTorrents(torrent_ids_t const& torrentIds = {});
-    void startTorrents(torrent_ids_t const& torrentIds = {});
-    void startTorrentsNow(torrent_ids_t const& torrentIds = {});
+    void pauseTorrents(torrent_ids_t const& torrent_ids = {});
+    void startTorrents(torrent_ids_t const& torrent_ids = {});
+    void startTorrentsNow(torrent_ids_t const& torrent_ids = {});
     void refreshDetailInfo(torrent_ids_t const& torrent_ids);
     void refreshActiveTorrents();
     void refreshAllTorrents();
     void addNewlyCreatedTorrent(QString const& filename, QString const& local_path);
     void verifyTorrents(torrent_ids_t const& torrent_ids);
     void reannounceTorrents(torrent_ids_t const& torrent_ids);
-    void refreshExtraStats(torrent_ids_t const& ids);
+    void refreshExtraStats(torrent_ids_t const& torrent_ids);
 
     enum class TorrentProperties
     {
@@ -117,7 +117,7 @@ public:
     };
 
 public slots:
-    void addTorrent(AddData addme);
+    void addTorrent(AddData add_me);
     void launchWebInterface() const;
     void queueMoveBottom(torrent_ids_t const& torrentIds = {});
     void queueMoveDown(torrent_ids_t const& torrentIds = {});
@@ -148,19 +148,19 @@ private slots:
 private:
     void start();
 
-    void updateStats(tr_variant* args);
-    void updateInfo(tr_variant* args);
+    void updateStats(tr_variant* args_dict);
+    void updateInfo(tr_variant* args_dict);
 
     Tag torrentSetImpl(tr_variant* args);
-    void sessionSet(tr_quark const key, QVariant const& variant);
+    void sessionSet(tr_quark const key, QVariant const& value);
     void pumpRequests();
     void sendTorrentRequest(std::string_view request, torrent_ids_t const& torrent_ids);
     void refreshTorrents(torrent_ids_t const& ids, TorrentProperties props);
     std::vector<std::string_view> const& getKeyNames(TorrentProperties props);
 
-    static void updateStats(tr_variant* d, tr_session_stats* stats);
+    static void updateStats(tr_variant* args_dict, tr_session_stats* stats);
 
-    void addOptionalIds(tr_variant* args, torrent_ids_t const& ids) const;
+    void addOptionalIds(tr_variant* args_dict, torrent_ids_t const& torrent_ids) const;
 
     QString const config_dir_;
     Prefs& prefs_;
@@ -170,8 +170,8 @@ private:
     int64_t blocklist_size_ = -1;
     tr_session* session_ = {};
     QStringList idle_json_;
-    tr_session_stats stats_ = {};
-    tr_session_stats cumulative_stats_ = {};
+    tr_session_stats stats_ = EmptyStats;
+    tr_session_stats cumulative_stats_ = EmptyStats;
     QString session_version_;
     QString session_id_;
     bool is_definitely_local_session_ = true;
@@ -180,4 +180,6 @@ private:
 
     std::map<QString, QString> duplicates_;
     QTimer duplicates_timer_;
+
+    static auto constexpr EmptyStats = tr_session_stats{ TR_RATIO_NA, 0, 0, 0, 0, 0 };
 };
diff --git a/qt/SqueezeLabel.cc b/qt/SqueezeLabel.cc
index 1bdf3bef0..49bcd54db 100644
--- a/qt/SqueezeLabel.cc
+++ b/qt/SqueezeLabel.cc
@@ -55,11 +55,11 @@ SqueezeLabel::SqueezeLabel(QWidget* parent)
 {
 }
 
-void SqueezeLabel::paintEvent(QPaintEvent* paintEvent)
+void SqueezeLabel::paintEvent(QPaintEvent* paint_event)
 {
     if (hasFocus() && (textInteractionFlags() & (Qt::TextSelectableByKeyboard | Qt::TextSelectableByMouse)) != 0)
     {
-        return QLabel::paintEvent(paintEvent);
+        return QLabel::paintEvent(paint_event);
     }
 
     QPainter painter(this);
diff --git a/qt/TorrentDelegate.cc b/qt/TorrentDelegate.cc
index 8e901200f..f9edba389 100644
--- a/qt/TorrentDelegate.cc
+++ b/qt/TorrentDelegate.cc
@@ -398,7 +398,7 @@ QString TorrentDelegate::statusString(Torrent const& tor)
 
 QSize TorrentDelegate::sizeHint(QStyleOptionViewItem const& option, Torrent const& tor) const
 {
-    auto const m = QSize(margin(*QApplication::style()));
+    auto const m = margin(*QApplication::style());
     auto const layout = ItemLayout(
         tor.name(),
         progressString(tor),
diff --git a/qt/TorrentDelegateMin.cc b/qt/TorrentDelegateMin.cc
index d2f020a5d..6d9b92155 100644
--- a/qt/TorrentDelegateMin.cc
+++ b/qt/TorrentDelegateMin.cc
@@ -108,7 +108,7 @@ ItemLayout::ItemLayout(
     int const icon_size = style->pixelMetric(QStyle::PM_SmallIconSize);
 
     auto const name_fm = QFontMetrics(name_font);
-    auto const name_size = QSize(name_fm.size(0, name_text_));
+    auto const name_size = name_fm.size(0, name_text_);
 
     status_font.setPointSize(static_cast<int>(status_font.pointSize() * 0.85));
     QFontMetrics const status_fm(status_font);
@@ -148,8 +148,8 @@ ItemLayout::ItemLayout(
 
 QSize TorrentDelegateMin::sizeHint(QStyleOptionViewItem const& option, Torrent const& tor) const
 {
-    auto const is_magnet = bool(!tor.hasMetadata());
-    auto const m = QSize(margin(*QApplication::style()));
+    auto const is_magnet = !tor.hasMetadata();
+    auto const m = margin(*QApplication::style());
     auto const layout = ItemLayout(
         is_magnet ? progressString(tor) : tor.name(),
         shortStatusString(tor),
diff --git a/qt/TorrentModel.cc b/qt/TorrentModel.cc
index 9074e53c4..0ff978a67 100644
--- a/qt/TorrentModel.cc
+++ b/qt/TorrentModel.cc
@@ -118,14 +118,14 @@ QVariant TorrentModel::data(QModelIndex const& index, int role) const
 ****
 ***/
 
-void TorrentModel::removeTorrents(tr_variant* list)
+void TorrentModel::removeTorrents(tr_variant* torrent_list)
 {
-    torrents_t torrents;
-    torrents.reserve(tr_variantListSize(list));
+    auto torrents = torrents_t{};
+    torrents.reserve(tr_variantListSize(torrent_list));
 
     int i = 0;
     tr_variant const* child = nullptr;
-    while ((child = tr_variantListChild(list, i++)) != nullptr)
+    while ((child = tr_variantListChild(torrent_list, i++)) != nullptr)
     {
         if (auto const id = getValue<int>(child); id)
         {
@@ -142,7 +142,7 @@ void TorrentModel::removeTorrents(tr_variant* list)
     }
 }
 
-void TorrentModel::updateTorrents(tr_variant* torrents, bool is_complete_list)
+void TorrentModel::updateTorrents(tr_variant* torrent_list, bool is_complete_list)
 {
     auto const old = is_complete_list ? torrents_ : torrents_t{};
     auto added = torrent_ids_t{};
@@ -163,7 +163,7 @@ void TorrentModel::updateTorrents(tr_variant* torrents, bool is_complete_list)
     };
 
     // build a list of the property keys
-    tr_variant* const first_child = tr_variantListChild(torrents, 0);
+    tr_variant* const first_child = tr_variantListChild(torrent_list, 0);
     bool const table = tr_variantIsList(first_child);
     std::vector<tr_quark> keys;
     if (table)
@@ -202,9 +202,9 @@ void TorrentModel::updateTorrents(tr_variant* torrents, bool is_complete_list)
     std::vector<tr_variant*> values;
     values.reserve(keys.size());
     size_t tor_index = table ? 1 : 0;
-    processed.reserve(tr_variantListSize(torrents));
+    processed.reserve(tr_variantListSize(torrent_list));
     tr_variant* v = nullptr;
-    while ((v = tr_variantListChild(torrents, tor_index++)))
+    while ((v = tr_variantListChild(torrent_list, tor_index++)))
     {
         // Build an array of values
         values.clear();
diff --git a/qt/VariantHelpers.cc b/qt/VariantHelpers.cc
index 0e127b0ab..ef6b036a9 100644
--- a/qt/VariantHelpers.cc
+++ b/qt/VariantHelpers.cc
@@ -31,10 +31,10 @@ bool change(double& setme, double const& value)
     return changed;
 }
 
-bool change(Speed& setme, tr_variant const* variant)
+bool change(Speed& setme, tr_variant const* value)
 {
-    auto const value = getValue<int>(variant);
-    return value && change(setme, Speed::fromBps(*value));
+    auto const bytes_per_second = getValue<int>(value);
+    return bytes_per_second && change(setme, Speed::fromBps(*bytes_per_second));
 }
 
 bool change(TorrentHash& setme, tr_variant const* value)