diff --git a/gtk/Application.cc b/gtk/Application.cc
index 4c2c671a2..9e535c8b4 100644
--- a/gtk/Application.cc
+++ b/gtk/Application.cc
@@ -423,9 +423,8 @@ bool Application::Impl::on_rpc_changed_idle(tr_rpc_callback_type type, int torre
             for (int i = 0; tr_variantDictChild(&tmp, i, &key, &newval); ++i)
             {
                 bool changed;
-                tr_variant const* oldval = tr_variantDictFind(oldvals, key);
 
-                if (oldval == nullptr)
+                if (tr_variant const* oldval = tr_variantDictFind(oldvals, key); oldval == nullptr)
                 {
                     changed = true;
                 }
@@ -1045,20 +1044,15 @@ void Application::Impl::on_prefs_changed(tr_quark const key)
         break;
 
     case TR_KEY_show_notification_area_icon:
+        if (bool const show = gtr_pref_flag_get(key); show && icon_ == nullptr)
         {
-            bool const show = gtr_pref_flag_get(key);
-
-            if (show && icon_ == nullptr)
-            {
-                icon_ = std::make_unique<SystemTrayIcon>(*wind_, core_);
-            }
-            else if (!show && icon_ != nullptr)
-            {
-                icon_.reset();
-            }
-
-            break;
+            icon_ = std::make_unique<SystemTrayIcon>(*wind_, core_);
         }
+        else if (!show && icon_ != nullptr)
+        {
+            icon_.reset();
+        }
+        break;
 
     case TR_KEY_speed_limit_down_enabled:
         tr_sessionLimitSpeed(tr, TR_DOWN, gtr_pref_flag_get(key));
@@ -1359,9 +1353,8 @@ tr_torrent* Application::Impl::get_first_selected_torrent() const
 {
     tr_torrent* tor = nullptr;
     Glib::RefPtr<Gtk::TreeModel> m;
-    auto const l = sel_->get_selected_rows(m);
 
-    if (!l.empty())
+    if (auto const l = sel_->get_selected_rows(m); !l.empty())
     {
         if (auto iter = m->get_iter(l.front()); iter)
         {
diff --git a/gtk/FileList.cc b/gtk/FileList.cc
index 8f3b15430..dc747d223 100644
--- a/gtk/FileList.cc
+++ b/gtk/FileList.cc
@@ -556,9 +556,8 @@ void renderDownload(Gtk::CellRenderer* renderer, Gtk::TreeModel::iterator const&
 void renderPriority(Gtk::CellRenderer* renderer, Gtk::TreeModel::iterator const& iter)
 {
     Glib::ustring text;
-    auto const priority = iter->get_value(file_cols.priority);
 
-    switch (priority)
+    switch (auto const priority = iter->get_value(file_cols.priority); priority)
     {
     case TR_PRI_HIGH:
         text = _("High");
diff --git a/gtk/MainWindow.cc b/gtk/MainWindow.cc
index f2bb75359..a23a0c422 100644
--- a/gtk/MainWindow.cc
+++ b/gtk/MainWindow.cc
@@ -588,9 +588,7 @@ void MainWindow::Impl::updateStats()
     auto const* const session = core_->get_session();
 
     /* update the stats */
-    auto const pch = gtr_pref_string_get(TR_KEY_statusbar_stats);
-
-    if (pch == "session-ratio")
+    if (auto const pch = gtr_pref_string_get(TR_KEY_statusbar_stats); pch == "session-ratio")
     {
         tr_sessionGetStats(session, &stats);
         buf = gtr_sprintf(_("Ratio: %s"), tr_strlratio(stats.ratio));
diff --git a/gtk/MakeDialog.cc b/gtk/MakeDialog.cc
index 98b435b87..7b7188799 100644
--- a/gtk/MakeDialog.cc
+++ b/gtk/MakeDialog.cc
@@ -390,11 +390,10 @@ void MakeDialog::Impl::on_drag_data_received(
     guint time_)
 {
     bool success = false;
-    auto const uris = selection_data.get_uris();
 
-    if (!uris.empty())
+    if (auto const uris = selection_data.get_uris(); !uris.empty())
     {
-        auto const uri = uris.front();
+        auto const& uri = uris.front();
         auto const filename = Glib::filename_from_uri(uri);
 
         if (Glib::file_test(filename, Glib::FILE_TEST_IS_DIR))
diff --git a/gtk/Utils.cc b/gtk/Utils.cc
index 04e7442d3..94e2739f5 100644
--- a/gtk/Utils.cc
+++ b/gtk/Utils.cc
@@ -421,11 +421,11 @@ Gtk::ComboBox* gtr_combo_box_new_enum(std::vector<std::pair<Glib::ustring, int>>
 {
     auto store = Gtk::ListStore::create(enum_combo_cols);
 
-    for (auto const& item : items)
+    for (auto const& [label, value] : items)
     {
         auto const iter = store->append();
-        (*iter)[enum_combo_cols.value] = item.second;
-        (*iter)[enum_combo_cols.label] = item.first;
+        (*iter)[enum_combo_cols.value] = value;
+        (*iter)[enum_combo_cols.label] = label;
     }
 
     auto w = Gtk::make_managed<Gtk::ComboBox>(static_cast<Glib::RefPtr<Gtk::TreeModel> const&>(store));
diff --git a/libtransmission/announcer-http.cc b/libtransmission/announcer-http.cc
index 66186d66b..93117a640 100644
--- a/libtransmission/announcer-http.cc
+++ b/libtransmission/announcer-http.cc
@@ -86,8 +86,7 @@ static std::string announce_url_new(tr_session const* session, tr_announce_reque
         evbuffer_add_printf(buf, "&corrupt=%" PRIu64, req->corrupt);
     }
 
-    char const* str = get_event_string(req);
-    if (!tr_str_is_empty(str))
+    if (char const* str = get_event_string(req); !tr_str_is_empty(str))
     {
         evbuffer_add_printf(buf, "&event=%s", str);
     }
diff --git a/libtransmission/announcer.cc b/libtransmission/announcer.cc
index 89ea048a2..972023e08 100644
--- a/libtransmission/announcer.cc
+++ b/libtransmission/announcer.cc
@@ -168,7 +168,6 @@ struct tr_announcer
     explicit tr_announcer(tr_session* session_in)
         : session{ session_in }
         , upkeep_timer{ evtimer_new(session_in->event_base, onUpkeepTimer, this) }
-        , key{ tr_rand_int(INT_MAX) }
     {
         scheduleNextUpdate();
     }
@@ -188,7 +187,7 @@ struct tr_announcer
 
     tr_session* const session;
     event* const upkeep_timer;
-    int const key;
+    int const key = tr_rand_int(INT_MAX);
     time_t tau_upkeep_at = 0;
 };
 
@@ -591,8 +590,7 @@ static void publishMessage(tr_tier* tier, std::string_view msg, TrackerEventType
         event.messageType = type;
         event.text = msg;
 
-        auto* const current_tracker = tier->currentTracker();
-        if (current_tracker != nullptr)
+        if (auto const* const current_tracker = tier->currentTracker(); current_tracker != nullptr)
         {
             event.announce_url = current_tracker->announce_url;
         }
@@ -865,7 +863,7 @@ void tr_announcerRemoveTorrent(tr_announcer* announcer, tr_torrent* tor)
         return;
     }
 
-    for (auto& tier : ta->tiers)
+    for (auto const& tier : ta->tiers)
     {
         if (tier.isRunning)
         {
@@ -1405,7 +1403,7 @@ static void multiscrape(tr_announcer* announcer, std::vector<tr_tier*> const& ti
         /* otherwise, if there's room for another request, build a new one */
         if (!found && request_count < MaxScrapesPerUpkeep)
         {
-            auto* const req = &requests[request_count++];
+            auto* const req = &requests[request_count];
             req->scrape_url = scrape_info->scrape_url;
             tier->buildLogName(req->log_name, sizeof(req->log_name));
 
@@ -1413,6 +1411,8 @@ static void multiscrape(tr_announcer* announcer, std::vector<tr_tier*> const& ti
             ++req->info_hash_count;
             tier->isScraping = true;
             tier->lastScrapeStartTime = now;
+
+            ++request_count;
         }
     }
 
diff --git a/libtransmission/handshake.cc b/libtransmission/handshake.cc
index b9f0081c0..f3b945200 100644
--- a/libtransmission/handshake.cc
+++ b/libtransmission/handshake.cc
@@ -26,11 +26,11 @@
 using namespace std::literals;
 
 /* enable LibTransmission extension protocol */
-#define ENABLE_LTEP * /
+#define ENABLE_LTEP
 /* fast extensions */
-#define ENABLE_FAST * /
+#define ENABLE_FAST
 /* DHT */
-#define ENABLE_DHT * /
+#define ENABLE_DHT
 
 /***
 ****
diff --git a/libtransmission/torrent.h b/libtransmission/torrent.h
index 2f9e6dc74..228ef0b13 100644
--- a/libtransmission/torrent.h
+++ b/libtransmission/torrent.h
@@ -151,55 +151,55 @@ public:
 
     [[nodiscard]] constexpr auto blockCount() const
     {
-        return blockInfo().blockCount();
+        return metainfo_.blockCount();
     }
     [[nodiscard]] constexpr auto blockOf(uint64_t offset) const
     {
-        return blockInfo().blockOf(offset);
+        return metainfo_.blockOf(offset);
     }
     [[nodiscard]] constexpr auto blockOf(tr_piece_index_t piece, uint32_t offset, uint32_t length = 0) const
     {
-        return blockInfo().blockOf(piece, offset, length);
+        return metainfo_.blockOf(piece, offset, length);
     }
     [[nodiscard]] constexpr auto blockSize() const
     {
-        return blockInfo().blockSize();
+        return metainfo_.blockSize();
     }
     [[nodiscard]] constexpr auto blockSize(tr_block_index_t block) const
     {
-        return blockInfo().blockSize(block);
+        return metainfo_.blockSize(block);
     }
     [[nodiscard]] constexpr auto blockSpanForPiece(tr_piece_index_t piece) const
     {
-        return blockInfo().blockSpanForPiece(piece);
+        return metainfo_.blockSpanForPiece(piece);
     }
     [[nodiscard]] constexpr auto offset(tr_piece_index_t piece, uint32_t offset, uint32_t length = 0) const
     {
-        return blockInfo().offset(piece, offset, length);
+        return metainfo_.offset(piece, offset, length);
     }
     [[nodiscard]] constexpr auto pieceCount() const
     {
-        return blockInfo().pieceCount();
+        return metainfo_.pieceCount();
     }
     [[nodiscard]] constexpr auto pieceForBlock(tr_block_index_t block) const
     {
-        return blockInfo().pieceForBlock(block);
+        return metainfo_.pieceForBlock(block);
     }
     [[nodiscard]] constexpr auto pieceOf(uint64_t offset) const
     {
-        return blockInfo().pieceOf(offset);
+        return metainfo_.pieceOf(offset);
     }
     [[nodiscard]] constexpr auto pieceSize() const
     {
-        return blockInfo().pieceSize();
+        return metainfo_.pieceSize();
     }
     [[nodiscard]] constexpr auto pieceSize(tr_piece_index_t piece) const
     {
-        return blockInfo().pieceSize(piece);
+        return metainfo_.pieceSize(piece);
     }
     [[nodiscard]] constexpr auto totalSize() const
     {
-        return blockInfo().totalSize();
+        return metainfo_.totalSize();
     }
 
     /// COMPLETION
diff --git a/libtransmission/utils.cc b/libtransmission/utils.cc
index 6d2cd1641..cd87fb740 100644
--- a/libtransmission/utils.cc
+++ b/libtransmission/utils.cc
@@ -298,7 +298,7 @@ uint8_t* tr_loadFile(char const* path, size_t* size, tr_error** error)
     {
         tr_logAddError(err_fmt, path, my_error->message);
         tr_sys_file_close(fd, nullptr);
-        free(buf);
+        tr_free(buf);
         tr_error_propagate(error, &my_error);
         return nullptr;
     }
diff --git a/libtransmission/variant.cc b/libtransmission/variant.cc
index caa0e4fbd..d860213d9 100644
--- a/libtransmission/variant.cc
+++ b/libtransmission/variant.cc
@@ -829,6 +829,7 @@ protected:
         }
     }
 
+private:
     // When walking `v`'s children, this is the index of the next child
     size_t child_index = 0;
 
diff --git a/qt/MainWindow.cc b/qt/MainWindow.cc
index fc3e5a39b..b0042a1fd 100644
--- a/qt/MainWindow.cc
+++ b/qt/MainWindow.cc
@@ -262,10 +262,10 @@ MainWindow::MainWindow(Session& session, Prefs& prefs, TorrentModel& model, bool
     // NOLINTNEXTLINE(clang-analyzer-cplusplus.NewDeleteLeaks)
     auto* action_group = new QActionGroup(this);
 
-    for (auto const& mode : sort_modes)
+    for (auto const& [action, mode] : sort_modes)
     {
-        mode.first->setProperty(SortModeKey, mode.second);
-        action_group->addAction(mode.first);
+        action->setProperty(SortModeKey, mode);
+        action_group->addAction(action);
     }
 
     connect(action_group, &QActionGroup::triggered, this, &MainWindow::onSortModeChanged);
@@ -1605,8 +1605,8 @@ bool MainWindow::event(QEvent* e)
         return QMainWindow::event(e);
     }
 
-    QString const text = QGuiApplication::clipboard()->text().trimmed();
-    if (text.endsWith(QStringLiteral(".torrent"), Qt::CaseInsensitive) ||
+    if (auto const text = QGuiApplication::clipboard()->text().trimmed();
+        text.endsWith(QStringLiteral(".torrent"), Qt::CaseInsensitive) ||
         text.startsWith(QStringLiteral("magnet:"), Qt::CaseInsensitive))
     {
         for (QString const& entry : text.split(QLatin1Char('\n')))
diff --git a/qt/RpcQueue.h b/qt/RpcQueue.h
index 37be9e120..2891c3a04 100644
--- a/qt/RpcQueue.h
+++ b/qt/RpcQueue.h
@@ -70,8 +70,8 @@ private:
     // normal closure, takes response and returns new future
     template<
         typename Func,
-        typename std::enable_if<
-            std::is_same_v<typename std::invoke_result_t<Func, RpcResponse const&>, RpcResponseFuture>>::type* = nullptr>
+        typename std::enable_if_t<std::is_same_v<typename std::invoke_result_t<Func, RpcResponse const&>, RpcResponseFuture>>* =
+            nullptr>
     QueuedFunction normalizeFunc(Func const& func) const
     {
         return [func](RpcResponseFuture const& r)
@@ -83,7 +83,7 @@ private:
     // closure without argument (first step), takes nothing and returns new future
     template<
         typename Func,
-        typename std::enable_if<std::is_same_v<typename std::invoke_result_t<Func>, RpcResponseFuture>>::type* = nullptr>
+        typename std::enable_if_t<std::is_same_v<typename std::invoke_result_t<Func>, RpcResponseFuture>>* = nullptr>
     QueuedFunction normalizeFunc(Func const& func) const
     {
         return [func](RpcResponseFuture const&)
@@ -95,7 +95,7 @@ private:
     // closure without return value ("auxiliary"), takes response and returns nothing
     template<
         typename Func,
-        typename std::enable_if<std::is_same_v<typename std::invoke_result_t<Func, RpcResponse const&>, void>>::type* = nullptr>
+        typename std::enable_if_t<std::is_same_v<typename std::invoke_result_t<Func, RpcResponse const&>, void>>* = nullptr>
     QueuedFunction normalizeFunc(Func const& func) const
     {
         return [func](RpcResponseFuture const& r)
@@ -106,7 +106,7 @@ private:
     }
 
     // closure without argument and return value, takes nothing and returns nothing -- next function will also get nothing
-    template<typename Func, typename std::enable_if<std::is_same_v<typename std::invoke_result_t<Func>, void>>::type* = nullptr>
+    template<typename Func, typename std::enable_if_t<std::is_same_v<typename std::invoke_result_t<Func>, void>>* = nullptr>
     QueuedFunction normalizeFunc(Func const& func) const
     {
         return [func](RpcResponseFuture const&)
@@ -119,7 +119,7 @@ private:
     // normal error handler, takes last response
     template<
         typename Func,
-        typename std::enable_if<std::is_same_v<typename std::invoke_result_t<Func, RpcResponse const&>, void>>::type* = nullptr>
+        typename std::enable_if_t<std::is_same_v<typename std::invoke_result_t<Func, RpcResponse const&>, void>>* = nullptr>
     ErrorHandlerFunction normalizeErrorHandler(Func const& func) const
     {
         return [func](RpcResponseFuture const& r)
@@ -129,7 +129,7 @@ private:
     }
 
     // error handler without an argument, takes nothing
-    template<typename Func, typename std::enable_if<std::is_same_v<typename std::invoke_result_t<Func>, void>>::type* = nullptr>
+    template<typename Func, typename std::enable_if_t<std::is_same_v<typename std::invoke_result_t<Func>, void>>* = nullptr>
     ErrorHandlerFunction normalizeErrorHandler(Func const& func) const
     {
         return [func](RpcResponseFuture const&)
diff --git a/qt/Session.cc b/qt/Session.cc
index 32ee9167e..0c5944dfe 100644
--- a/qt/Session.cc
+++ b/qt/Session.cc
@@ -1115,9 +1115,9 @@ void Session::onDuplicatesTimer()
     duplicates.swap(duplicates_);
 
     QStringList lines;
-    for (auto it : duplicates)
+    for (auto [dupe, original] : duplicates)
     {
-        lines.push_back(tr("%1 (copy of %2)").arg(it.first).arg(it.second.left(7)));
+        lines.push_back(tr("%1 (copy of %2)").arg(dupe).arg(original.left(7)));
     }
 
     if (!lines.empty())
diff --git a/qt/TorrentModel.cc b/qt/TorrentModel.cc
index ca551960f..fe777f328 100644
--- a/qt/TorrentModel.cc
+++ b/qt/TorrentModel.cc
@@ -342,10 +342,10 @@ std::optional<int> TorrentModel::getRow(int id) const
 {
     std::optional<int> row;
 
-    auto const it = std::equal_range(torrents_.begin(), torrents_.end(), id, TorrentIdLessThan());
-    if (it.first != it.second)
+    auto const [begin, end] = std::equal_range(torrents_.begin(), torrents_.end(), id, TorrentIdLessThan());
+    if (begin != end)
     {
-        row = std::distance(torrents_.begin(), it.first);
+        row = std::distance(torrents_.begin(), begin);
         assert(torrents_[*row]->id() == id);
     }
 
@@ -425,9 +425,9 @@ std::vector<TorrentModel::span_t> TorrentModel::getSpans(torrent_ids_t const& id
 
 void TorrentModel::rowsEmitChanged(torrent_ids_t const& ids)
 {
-    for (auto const& span : getSpans(ids))
+    for (auto const& [first, last] : getSpans(ids))
     {
-        emit dataChanged(index(span.first), index(span.second));
+        emit dataChanged(index(first), index(last));
     }
 }
 
@@ -462,10 +462,10 @@ void TorrentModel::rowsRemove(torrents_t const& torrents)
     auto const& spans = getSpans(getIds(torrents.begin(), torrents.end()));
     for (auto it = spans.rbegin(), end = spans.rend(); it != end; ++it)
     {
-        auto const& span = *it;
+        auto const& [first, last] = *it;
 
-        beginRemoveRows(QModelIndex(), span.first, span.second);
-        torrents_.erase(torrents_.begin() + span.first, torrents_.begin() + span.second + 1);
+        beginRemoveRows(QModelIndex(), first, last);
+        torrents_.erase(torrents_.begin() + first, torrents_.begin() + last + 1);
         endRemoveRows();
     }
 
diff --git a/qt/VariantHelpers.h b/qt/VariantHelpers.h
index 3f96d3c86..099bc44da 100644
--- a/qt/VariantHelpers.h
+++ b/qt/VariantHelpers.h
@@ -28,7 +28,7 @@ namespace trqt
 namespace variant_helpers
 {
 
-template<typename T, typename std::enable_if<std::is_same_v<T, bool>>::type* = nullptr>
+template<typename T, typename std::enable_if_t<std::is_same_v<T, bool>>* = nullptr>
 auto getValue(tr_variant const* variant)
 {
     std::optional<T> ret;
@@ -43,9 +43,9 @@ auto getValue(tr_variant const* variant)
 
 template<
     typename T,
-    typename std::enable_if<
-        std::is_same_v<T, int64_t> || std::is_same_v<T, uint64_t> || std::is_same_v<T, int> ||
-        std::is_same_v<T, time_t>>::type* = nullptr>
+    typename std::enable_if_t<
+        std::is_same_v<T, int64_t> || std::is_same_v<T, uint64_t> || std::is_same_v<T, int> || std::is_same_v<T, time_t>>* =
+        nullptr>
 auto getValue(tr_variant const* variant)
 {
     std::optional<T> ret;
@@ -58,7 +58,7 @@ auto getValue(tr_variant const* variant)
     return ret;
 }
 
-template<typename T, typename std::enable_if<std::is_same_v<T, double>>::type* = nullptr>
+template<typename T, typename std::enable_if_t<std::is_same_v<T, double>>* = nullptr>
 auto getValue(tr_variant const* variant)
 {
     std::optional<T> ret;
@@ -71,7 +71,7 @@ auto getValue(tr_variant const* variant)
     return ret;
 }
 
-template<typename T, typename std::enable_if<std::is_same_v<T, QString>>::type* = nullptr>
+template<typename T, typename std::enable_if_t<std::is_same_v<T, QString>>* = nullptr>
 auto getValue(tr_variant const* variant)
 {
     std::optional<T> ret;
@@ -84,7 +84,7 @@ auto getValue(tr_variant const* variant)
     return ret;
 }
 
-template<typename T, typename std::enable_if<std::is_same_v<T, std::string_view>>::type* = nullptr>
+template<typename T, typename std::enable_if_t<std::is_same_v<T, std::string_view>>* = nullptr>
 auto getValue(tr_variant const* variant)
 {
     std::optional<T> ret;
@@ -100,8 +100,8 @@ auto getValue(tr_variant const* variant)
 template<
     typename C,
     typename T = typename C::value_type,
-    typename std::enable_if<
-        std::is_same_v<C, QStringList> || std::is_same_v<C, QList<T>> || std::is_same_v<C, std::vector<T>>>::type* = nullptr>
+    typename std::enable_if_t<
+        std::is_same_v<C, QStringList> || std::is_same_v<C, QList<T>> || std::is_same_v<C, std::vector<T>>>* = nullptr>
 auto getValue(tr_variant const* variant)
 {
     std::optional<C> ret;
diff --git a/utils/show.cc b/utils/show.cc
index 2eb77396e..52f66e4e8 100644
--- a/utils/show.cc
+++ b/utils/show.cc
@@ -156,8 +156,7 @@ void showInfo(app_opts const& opts, tr_torrent_metainfo const& metainfo)
     ***
     **/
 
-    auto const n_webseeds = metainfo.webseedCount();
-    if (n_webseeds > 0)
+    if (auto const n_webseeds = metainfo.webseedCount(); n_webseeds > 0)
     {
         printf("\nWEBSEEDS\n\n");
 
@@ -242,8 +241,7 @@ void doScrape(tr_torrent_metainfo const& metainfo)
         // execute the http scrape
         curl_easy_setopt(curl, CURLOPT_URL, url.c_str());
         curl_easy_setopt(curl, CURLOPT_TIMEOUT, TimeoutSecs);
-        auto const res = curl_easy_perform(curl);
-        if (res != CURLE_OK)
+        if (auto const res = curl_easy_perform(curl); res != CURLE_OK)
         {
             printf("error: %s\n", curl_easy_strerror(res));
             continue;