Deprecate conversion functions between QList and QSet

Users should use range constructors instead to do the conversion.
Keep conversion methods between QList and QVector as these will turn
into a no-op in Qt 6, whereas forcing people to use range constructors
would lead to deep copies of the data.

Change-Id: Id9fc9e4d007044e019826da523e8418857c91283
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

14 files changed, 37 insertions, 30 deletions

diff --git a/src/corelib/statemachine/qstatemachine.cpp b/src/corelib/statemachine/qstatemachine.cpp
index ee3f7be279..be48dbc92f 100644
--- a/src/corelib/statemachine/qstatemachine.cpp
+++ b/src/corelib/statemachine/qstatemachine.cpp
@@ -370,10 +370,11 @@ static QList<QAbstractState *> getEffectiveTargetStates(QAbstractTransition *tra
             QList<QAbstractState*> historyConfiguration = QHistoryStatePrivate::get(historyState)->configuration;
             if (!historyConfiguration.isEmpty()) {
                 // There is a saved history, so apply that.
-                targets.unite(historyConfiguration.toSet());
+                targets.unite(QSet<QAbstractState *>(historyConfiguration.constBegin(), historyConfiguration.constEnd()));
             } else if (QAbstractTransition *defaultTransition = historyState->defaultTransition()) {
                 // No saved history, take all default transition targets.
-                targets.unite(defaultTransition->targetStates().toSet());
+                const auto &targetStates = defaultTransition->targetStates();
+                targets.unite(QSet<QAbstractState *>(targetStates.constBegin(), targetStates.constEnd()));
             } else {
                 // Woops, we found a history state without a default state. That's not valid!
                 QStateMachinePrivate *m = QStateMachinePrivate::get(historyState->machine());
@@ -384,7 +385,7 @@ static QList<QAbstractState *> getEffectiveTargetStates(QAbstractTransition *tra
         }
     }
 
-    targetsList = targets.toList();
+    targetsList = targets.values();
     cache->insert(transition, targetsList);
     return targetsList;
 }
@@ -740,7 +741,7 @@ QList<QAbstractState*> QStateMachinePrivate::computeExitSet(const QList<QAbstrac
 {
     Q_ASSERT(cache);
 
-    QList<QAbstractState*> statesToExit_sorted = computeExitSet_Unordered(enabledTransitions, cache).toList();
+    QList<QAbstractState*> statesToExit_sorted = computeExitSet_Unordered(enabledTransitions, cache).values();
     std::sort(statesToExit_sorted.begin(), statesToExit_sorted.end(), stateExitLessThan);
     return statesToExit_sorted;
 }
@@ -777,7 +778,7 @@ QSet<QAbstractState*> QStateMachinePrivate::computeExitSet_Unordered(QAbstractTr
         // makes the state machine invalid.
         if (error == QStateMachine::NoError)
             setError(QStateMachine::NoCommonAncestorForTransitionError, t->sourceState());
-        QList<QAbstractState *> lst = pendingErrorStates.toList();
+        QList<QAbstractState *> lst = pendingErrorStates.values();
         lst.prepend(t->sourceState());
 
         domain = findLCCA(lst);
@@ -879,7 +880,7 @@ QList<QAbstractState*> QStateMachinePrivate::computeEntrySet(const QList<QAbstra
         pendingErrorStatesForDefaultEntry.clear();
     }
 
-    QList<QAbstractState*> statesToEnter_sorted = statesToEnter.toList();
+    QList<QAbstractState*> statesToEnter_sorted = statesToEnter.values();
     std::sort(statesToEnter_sorted.begin(), statesToEnter_sorted.end(), stateEntryLessThan);
     return statesToEnter_sorted;
 }
diff --git a/src/corelib/tools/qlist.h b/src/corelib/tools/qlist.h
index 25380d45ec..04c1f12f5f 100644
--- a/src/corelib/tools/qlist.h
+++ b/src/corelib/tools/qlist.h
@@ -403,13 +403,15 @@ public:
     inline QList<T> &operator<<(const QList<T> &l)
     { *this += l; return *this; }
 
+    static QList<T> fromVector(const QVector<T> &vector);
     QVector<T> toVector() const;
-    QSet<T> toSet() const;
 
-    static QList<T> fromVector(const QVector<T> &vector);
+#if QT_VERSION < QT_VERSION_CHECK(6,0,0)
+    Q_DECL_DEPRECATED_X("Use QList<T>(set.begin(), set.end()) instead.")
     static QList<T> fromSet(const QSet<T> &set);
+    Q_DECL_DEPRECATED_X("Use QSet<T>(list.begin(), list.end()) instead.")
+    QSet<T> toSet() const;
 
-#if QT_VERSION < QT_VERSION_CHECK(6,0,0)
     Q_DECL_DEPRECATED_X("Use QList<T>(list.begin(), list.end()) instead.")
     static inline QList<T> fromStdList(const std::list<T> &list)
     { QList<T> tmp; std::copy(list.begin(), list.end(), std::back_inserter(tmp)); return tmp; }
diff --git a/src/corelib/tools/qset.h b/src/corelib/tools/qset.h
index 8b31de71a9..83e574bf1c 100644
--- a/src/corelib/tools/qset.h
+++ b/src/corelib/tools/qset.h
@@ -245,10 +245,13 @@ public:
     inline QSet<T> operator-(const QSet<T> &other) const
         { QSet<T> result = *this; result -= other; return result; }
 
-    QList<T> toList() const;
-    inline QList<T> values() const { return toList(); }
-
+    QList<T> values() const;
+#if QT_VERSION < QT_VERSION_CHECK(6,0,0)
+    Q_DECL_DEPRECATED_X("Use values() instead.")
+    QList<T> toList() const { return values(); }
+    Q_DECL_DEPRECATED_X("Use QSet<T>(list.begin(), list.end()) instead.")
     static QSet<T> fromList(const QList<T> &list);
+#endif
 
 private:
     Hash q_hash;
@@ -368,7 +371,7 @@ Q_INLINE_TEMPLATE bool QSet<T>::contains(const QSet<T> &other) const
 }
 
 template <typename T>
-Q_OUTOFLINE_TEMPLATE QList<T> QSet<T>::toList() const
+Q_OUTOFLINE_TEMPLATE QList<T> QSet<T>::values() const
 {
     QList<T> result;
     result.reserve(size());
@@ -380,6 +383,7 @@ Q_OUTOFLINE_TEMPLATE QList<T> QSet<T>::toList() const
     return result;
 }
 
+#if QT_VERSION < QT_VERSION_CHECK(6,0,0)
 template <typename T>
 Q_OUTOFLINE_TEMPLATE QSet<T> QList<T>::toSet() const
 {
@@ -401,6 +405,7 @@ QList<T> QList<T>::fromSet(const QSet<T> &set)
 {
     return set.toList();
 }
+#endif
 
 Q_DECLARE_SEQUENTIAL_ITERATOR(Set)
 
diff --git a/src/corelib/tools/qvector.h b/src/corelib/tools/qvector.h
index b763d6e7e2..492afeac75 100644
--- a/src/corelib/tools/qvector.h
+++ b/src/corelib/tools/qvector.h
@@ -297,9 +297,8 @@ public:
     inline QVector<T> &operator<<(T &&t)
     { append(std::move(t)); return *this; }
 
-    QList<T> toList() const;
-
     static QVector<T> fromList(const QList<T> &list);
+    QList<T> toList() const;
 
 #if QT_VERSION < QT_VERSION_CHECK(6,0,0)
     Q_DECL_DEPRECATED_X("Use QVector<T>(vector.begin(), vector.end()) instead.")
diff --git a/src/gui/opengl/qopengl.cpp b/src/gui/opengl/qopengl.cpp
index 6b701fe52b..667d16317f 100644
--- a/src/gui/opengl/qopengl.cpp
+++ b/src/gui/opengl/qopengl.cpp
@@ -80,7 +80,7 @@ QOpenGLExtensionMatcher::QOpenGLExtensionMatcher()
     if (extensionStr) {
         QByteArray ba(extensionStr);
         QList<QByteArray> extensions = ba.split(' ');
-        m_extensions = extensions.toSet();
+        m_extensions = QSet<QByteArray>(extensions.constBegin(), extensions.constEnd());
     } else {
 #ifdef QT_OPENGL_3
         // clear error state
diff --git a/src/gui/text/qtextodfwriter.cpp b/src/gui/text/qtextodfwriter.cpp
index a62e7e425a..8eaad403d0 100644
--- a/src/gui/text/qtextodfwriter.cpp
+++ b/src/gui/text/qtextodfwriter.cpp
@@ -1007,7 +1007,7 @@ bool QTextOdfWriter::writeAll()
 
     // add objects for lists, frames and tables
     const QVector<QTextFormat> allFormats = m_document->allFormats();
-    const QList<int> copy = formats.toList();
+    const QList<int> copy = formats.values();
     for (auto index : copy) {
         QTextObject *object = m_document->objectForFormat(allFormats[index]);
         if (object) {
diff --git a/src/network/ssl/qsslsocket_openssl_symbols.cpp b/src/network/ssl/qsslsocket_openssl_symbols.cpp
index e04d45c10c..6f935a02e4 100644
--- a/src/network/ssl/qsslsocket_openssl_symbols.cpp
+++ b/src/network/ssl/qsslsocket_openssl_symbols.cpp
@@ -693,7 +693,7 @@ static QStringList libraryPathList()
     // discover paths of already loaded libraries
     QSet<QString> loadedPaths;
     dl_iterate_phdr(dlIterateCallback, &loadedPaths);
-    paths.append(loadedPaths.toList());
+    paths.append(loadedPaths.values());
 #endif
 
     return paths;
diff --git a/src/tools/uic/cpp/cppwriteinitialization.cpp b/src/tools/uic/cpp/cppwriteinitialization.cpp
index a1ff26ba04..2510fd0edc 100644
--- a/src/tools/uic/cpp/cppwriteinitialization.cpp
+++ b/src/tools/uic/cpp/cppwriteinitialization.cpp
@@ -2607,7 +2607,7 @@ static void generateMultiDirectiveBegin(QTextStream &outputStream, const QSet<QS
         return;
     }
 
-    auto list = directives.toList();
+    auto list = directives.values();
     // sort (always generate in the same order):
     std::sort(list.begin(), list.end());
 
diff --git a/src/widgets/graphicsview/qgraphicsanchorlayout_p.cpp b/src/widgets/graphicsview/qgraphicsanchorlayout_p.cpp
index 008560d856..4f44373cad 100644
--- a/src/widgets/graphicsview/qgraphicsanchorlayout_p.cpp
+++ b/src/widgets/graphicsview/qgraphicsanchorlayout_p.cpp
@@ -2066,7 +2066,7 @@ QList<AnchorData *> getVariables(const QList<QSimplexConstraint *> &constraints)
         for (auto it = c->variables.cbegin(), end = c->variables.cend(); it != end; ++it)
             variableSet.insert(static_cast<AnchorData *>(it.key()));
     }
-    return variableSet.toList();
+    return variableSet.values();
 }
 
 /*!
diff --git a/src/widgets/graphicsview/qgraphicsscene.cpp b/src/widgets/graphicsview/qgraphicsscene.cpp
index 3897823e98..e5bd65d61e 100644
--- a/src/widgets/graphicsview/qgraphicsscene.cpp
+++ b/src/widgets/graphicsview/qgraphicsscene.cpp
@@ -6352,7 +6352,7 @@ void QGraphicsScenePrivate::gestureEventHandler(QGestureEvent *event)
                         << "delivering override to"
                         << item.data() << gestures;
                 // send gesture override
-                QGestureEvent ev(gestures.toList());
+                QGestureEvent ev(gestures.values());
                 ev.t = QEvent::GestureOverride;
                 ev.setWidget(event->widget());
                 // mark event and individual gestures as ignored
@@ -6442,7 +6442,7 @@ void QGraphicsScenePrivate::gestureEventHandler(QGestureEvent *event)
         DEBUG() << "QGraphicsScenePrivate::gestureEventHandler:"
                 << "delivering to"
                 << receiver.data() << gestures;
-        QGestureEvent ev(gestures.toList());
+        QGestureEvent ev(gestures.values());
         ev.setWidget(event->widget());
         sendEvent(receiver.data(), &ev);
         QSet<QGesture *> ignoredGestures;
@@ -6473,7 +6473,7 @@ void QGraphicsScenePrivate::gestureEventHandler(QGestureEvent *event)
             // look for new potential targets for gestures that were ignored
             // and should be propagated.
 
-            QSet<QGraphicsObject *> targetsSet = cachedTargetItems.toSet();
+            QSet<QGraphicsObject *> targetsSet(cachedTargetItems.constBegin(), cachedTargetItems.constEnd());
 
             if (receiver) {
                 // first if the gesture should be propagated to parents only
@@ -6505,7 +6505,7 @@ void QGraphicsScenePrivate::gestureEventHandler(QGestureEvent *event)
             gestureTargetsAtHotSpots(ignoredGestures, Qt::ReceivePartialGestures,
                                      &cachedItemGestures, &targetsSet, 0, 0);
 
-            cachedTargetItems = targetsSet.toList();
+            cachedTargetItems = targetsSet.values();
             std::sort(cachedTargetItems.begin(), cachedTargetItems.end(), qt_closestItemFirst);
             DEBUG() << "QGraphicsScenePrivate::gestureEventHandler:"
                     << "new targets:" << cachedTargetItems;
@@ -6583,7 +6583,7 @@ void QGraphicsScenePrivate::cancelGesturesForChildren(QGesture *original)
         }
         Q_ASSERT(target);
 
-        const QList<QGesture *> list = gestures.toList();
+        const QList<QGesture *> list = gestures.values();
         QGestureEvent ev(list);
         sendEvent(target, &ev);
 
diff --git a/src/widgets/graphicsview/qsimplex_p.cpp b/src/widgets/graphicsview/qsimplex_p.cpp
index e6ffa856f1..e18f1fa4c4 100644
--- a/src/widgets/graphicsview/qsimplex_p.cpp
+++ b/src/widgets/graphicsview/qsimplex_p.cpp
@@ -164,7 +164,7 @@ bool QSimplex::setConstraints(const QList<QSimplexConstraint *> &newConstraints)
         for (auto it = v.cbegin(), end = v.cend(); it != end; ++it)
             variablesSet.insert(it.key());
     }
-    variables = variablesSet.toList();
+    variables = variablesSet.values();
 
     // Set Variables reverse mapping
     // We also need to be able to find the index for a given variable, to do that
diff --git a/src/widgets/itemviews/qtableview.cpp b/src/widgets/itemviews/qtableview.cpp
index 9e9aa63b53..0e03ff2a97 100644
--- a/src/widgets/itemviews/qtableview.cpp
+++ b/src/widgets/itemviews/qtableview.cpp
@@ -191,7 +191,7 @@ QList<QSpanCollection::Span *> QSpanCollection::spansInRect(int x, int y, int w,
             break;
         --it_y;
     }
-    return list.toList();
+    return list.values();
 }
 
 #undef DEBUG_SPAN_UPDATE
@@ -875,7 +875,7 @@ void QTableViewPrivate::drawAndClipSpans(const QRegion &area, QPainter *painter,
             for(int y = firstVisualRow; y <= lastVisualRow; y++)
                 set.insert(spans.spanAt(x,y));
         set.remove(0);
-        visibleSpans = set.toList();
+        visibleSpans = set.values();
     }
 
     for (QSpanCollection::Span *span : qAsConst(visibleSpans)) {
diff --git a/src/widgets/kernel/qapplication.cpp b/src/widgets/kernel/qapplication.cpp
index c1c4014c6b..ca48a9e145 100644
--- a/src/widgets/kernel/qapplication.cpp
+++ b/src/widgets/kernel/qapplication.cpp
@@ -1721,7 +1721,7 @@ QWidgetList QApplication::topLevelWidgets()
 QWidgetList QApplication::allWidgets()
 {
     if (QWidgetPrivate::allWidgets)
-        return QWidgetPrivate::allWidgets->toList();
+        return QWidgetPrivate::allWidgets->values();
     return QWidgetList();
 }
 
diff --git a/src/widgets/kernel/qgesturemanager.cpp b/src/widgets/kernel/qgesturemanager.cpp
index cd27c9c5be..390602205c 100644
--- a/src/widgets/kernel/qgesturemanager.cpp
+++ b/src/widgets/kernel/qgesturemanager.cpp
@@ -171,7 +171,7 @@ void QGestureManager::cleanupCachedGestures(QObject *target, Qt::GestureType typ
     while (iter != m_objectGestures.end()) {
         ObjectGesture objectGesture = iter.key();
         if (objectGesture.gesture == type && target == objectGesture.object) {
-            QSet<QGesture *> gestures = iter.value().toSet();
+            QSet<QGesture *> gestures = QSet<QGesture *>(iter.value().constBegin(), iter.value().constEnd());
             for (QHash<QGestureRecognizer *, QSet<QGesture *> >::iterator
                  it = m_obsoleteGestures.begin(), e = m_obsoleteGestures.end(); it != e; ++it) {
                 it.value() -= gestures;