Silence warnings about deprecated QString::QString(const char*)

Fix warnings like:
src/qmllocalstorage/qqmllocalstorage.cpp:81:62: warning: QString::QString(const char*) is deprecated: Use fromUtf8, QStringLiteral, or QLatin1String [-Wdeprecated-declarations]
src/src/labs/settings/qqmlsettings.cpp:335:87: warning: QString::QString(const char*) is deprecated: Use fromUtf8, QStringLiteral, or QLatin1String [-Wdeprecated-declarations]
src/labs/settings/qqmlsettings.cpp:346:50: warning: QString::QString(const char*) is deprecated: Use fromUtf8, QStringLiteral, or n1String [-Wdeprecated-declarations]
src/labs/settings/qqmlsettings.cpp:361:50: warning: QString::QString(const char*) is deprecated: Use fromUtf8, QStringLiteral, or n1String [-Wdeprecated-declarations]
src/quicklayouts/qquicklayout.cpp:1241:61: warning: QString::QString(const char*) is deprecated: Use fromUtf8, QStringLiteral, or QLatin1String [-Wdeprecated-declarations]

Change-Id: I87d7e28842a4f7f75b02c1e78eb3df400adcab94
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>

3 files changed, 14 insertions, 9 deletions

diff --git a/src/labs/settings/qqmlsettings.cpp b/src/labs/settings/qqmlsettings.cpp
index ff8ec5e065..bf1ad021a7 100644
--- a/src/labs/settings/qqmlsettings.cpp
+++ b/src/labs/settings/qqmlsettings.cpp
@@ -330,9 +330,11 @@ void QQmlSettingsPrivate::load()
 
     for (int i = offset; i < count; ++i) {
         QMetaProperty property = mo->property(i);
+        const QString propertyName = QString::fromUtf8(property.name());
 
         const QVariant previousValue = readProperty(property);
-        const QVariant currentValue = instance()->value(property.name(), previousValue);
+        const QVariant currentValue = instance()->value(propertyName,
+                                                        previousValue);
 
         if (!currentValue.isNull() && (!previousValue.isValid()
                 || (currentValue.canConvert(previousValue.metaType())
@@ -343,7 +345,7 @@ void QQmlSettingsPrivate::load()
 
         // ensure that a non-existent setting gets written
         // even if the property wouldn't change later
-        if (!instance()->contains(property.name()))
+        if (!instance()->contains(propertyName))
             _q_propertyChanged();
 
         // setup change notifications on first load
@@ -358,7 +360,7 @@ void QQmlSettingsPrivate::store()
 {
     QHash<const char *, QVariant>::const_iterator it = changedProperties.constBegin();
     while (it != changedProperties.constEnd()) {
-        instance()->setValue(it.key(), it.value());
+        instance()->setValue(QString::fromUtf8(it.key()), it.value());
         qCDebug(lcSettings) << "QQmlSettings: store" << it.key() << ":" << it.value();
         ++it;
     }
diff --git a/src/qmllocalstorage/qqmllocalstorage.cpp b/src/qmllocalstorage/qqmllocalstorage.cpp
index 56b48189ba..8ab7c75ef7 100644
--- a/src/qmllocalstorage/qqmllocalstorage.cpp
+++ b/src/qmllocalstorage/qqmllocalstorage.cpp
@@ -78,7 +78,7 @@ QT_BEGIN_NAMESPACE
 }
 
 #define V4THROW_REFERENCE(string) { \
-    QV4::ScopedString v(scope, scope.engine->newString(string)); \
+    QV4::ScopedString v(scope, scope.engine->newString(QLatin1String(string))); \
     scope.engine->throwReferenceError(v); \
     RETURN_UNDEFINED(); \
 }
@@ -335,9 +335,12 @@ static ReturnedValue qmlsqldatabase_executeSql(const FunctionObject *b, const Va
             // XXX optimize
             ScopedString s(scope);
             ScopedValue v(scope);
-            resultObject->put((s = scope.engine->newIdentifier("rowsAffected")).getPointer(), (v = Value::fromInt32(query.numRowsAffected())));
-            resultObject->put((s = scope.engine->newIdentifier("insertId")).getPointer(), (v = scope.engine->newString(query.lastInsertId().toString())));
-            resultObject->put((s = scope.engine->newIdentifier("rows")).getPointer(), rows);
+            resultObject->put((s = scope.engine->newIdentifier(QLatin1String("rowsAffected"))).getPointer(),
+                              (v = Value::fromInt32(query.numRowsAffected())));
+            resultObject->put((s = scope.engine->newIdentifier(QLatin1String("insertId"))).getPointer(),
+                              (v = scope.engine->newString(query.lastInsertId().toString())));
+            resultObject->put((s = scope.engine->newIdentifier(QLatin1String("rows"))).getPointer(),
+                              rows);
         } else {
             err = true;
         }
diff --git a/src/quicklayouts/qquicklayout.cpp b/src/quicklayouts/qquicklayout.cpp
index dbbd25de85..7af6bd86af 100644
--- a/src/quicklayouts/qquicklayout.cpp
+++ b/src/quicklayouts/qquicklayout.cpp
@@ -1236,9 +1236,9 @@ void QQuickLayout::_q_dumpLayoutTree() const
 
 void QQuickLayout::dumpLayoutTreeRecursive(int level, QString &buf) const
 {
-    auto formatLine = [&level](const char *fmt) {
+    auto formatLine = [&level](const char *fmt) -> QString {
         QString ss(level *4, QLatin1Char(' '));
-        return QString::fromLatin1("%1%2\n").arg(ss).arg(fmt);
+        return ss + QLatin1String(fmt) + QLatin1Char('\n');
     };
 
     auto f2s = [](qreal f) {