code: Small cleanups and fixes to lambda captures (#6191)

Co-authored-by: v1993 <v19930312@gmail.com>
Co-authored-by: Morph <39850852+Morph1984@users.noreply.github.com>

src/citra_qt/game_list_p.h

@@ -320,6 +320,12 @@ public:
         setData(type(), TypeRole);
         setData(size_bytes, SizeRole);
     }
+    explicit GameListItemSize(const QString& string) {
+        // This is required to avoid incorrect virtual function call in
+        // GameListItem's constructor
+        setText(string);
+        setData(string, SortRole);
+    }
 
     void setData(const QVariant& value, int role) override {
         // By specializing setData for SizeRole, we can ensure that the numerical and string

src/citra_qt/multiplayer/lobby.cpp

@@ -30,12 +30,12 @@ Lobby::Lobby(QWidget* parent, QStandardItemModel* list,
     ui->setupUi(this);
 
     // setup the watcher for background connections
-    watcher = new QFutureWatcher<void>;
+    watcher = new QFutureWatcher<void>(this);
 
     model = new QStandardItemModel(ui->room_list);
 
     // Create a proxy to the game list to get the list of games owned
-    game_list = new QStandardItemModel;
+    game_list = new QStandardItemModel(this);
     UpdateGameList(list);
 
     proxy = new LobbyFilterProxyModel(this, game_list);

src/citra_qt/updater/updater.cpp

@@ -156,7 +156,7 @@ void UpdaterPrivate::StopUpdateCheck(int delay, bool async) {
             QTimer* timer = new QTimer(this);
             timer->setSingleShot(true);
 
-            connect(timer, &QTimer::timeout, [=]() {
+            connect(timer, &QTimer::timeout, [this, timer]() {
                 StopUpdateCheck(0, false);
                 timer->deleteLater();
             });

src/citra_qt/util/spinbox.cpp

@@ -76,10 +76,12 @@ void CSpinBox::stepBy(int steps) {
     }*/
 
     // Increment "new_value" by "steps", and perform annoying overflow checks, too.
-    if (steps < 0 && new_value + steps > new_value) {
-        new_value = std::numeric_limits<qint64>::min();
-    } else if (steps > 0 && new_value + steps < new_value) {
-        new_value = std::numeric_limits<qint64>::max();
+    constexpr qint64 qint64_min = std::numeric_limits<qint64>::min();
+    constexpr qint64 qint64_max = std::numeric_limits<qint64>::max();
+    if (steps < 0 && new_value < qint64_min - steps) {
+        new_value = qint64_min;
+    } else if (steps > 0 && new_value > qint64_max - steps) {
+        new_value = qint64_max;
     } else {
         new_value += steps;
     }