Avoid detaching temporary objects

Found with clazy [detaching-temporary]:
- don't call QList::first() on temporary
- don't call QString::operator[]() on temporary
- don't call QByteArray::data() on temporary

Change-Id: I390962ef6020e4fcb0b0e447a63eed1e314d18a4
Reviewed-by: Anton Kudryavtsev <antkudr@mail.ru>
Reviewed-by: Sérgio Martins <sergio.martins@kdab.com>

src/corelib/io/qfsfileengine_unix.cpp

@@ -629,7 +629,7 @@ QString QFSFileEngine::fileName(FileName file) const
 bool QFSFileEngine::isRelativePath() const
 {
     Q_D(const QFSFileEngine);
-    return d->fileEntry.filePath().length() ? d->fileEntry.filePath()[0] != QLatin1Char('/') : true;
+    return d->fileEntry.filePath().length() ? d->fileEntry.filePath().at(0) != QLatin1Char('/') : true;
 }
 
 uint QFSFileEngine::ownerId(FileOwner own) const

src/network/access/qnetworkdiskcache.cpp

@@ -606,7 +606,7 @@ QString QNetworkDiskCachePrivate::uniqueFileName(const QUrl &url)
     QCryptographicHash hash(QCryptographicHash::Sha1);
     hash.addData(cleanUrl.toEncoded());
     // convert sha1 to base36 form and return first 8 bytes for use as string
-    QByteArray id =  QByteArray::number(*(qlonglong*)hash.result().data(), 36).left(8);
+    const QByteArray id = QByteArray::number(*(qlonglong*)hash.result().constData(), 36).left(8);
     // generates <one-char subdir>/<8-char filname.d>
     uint code = (uint)id.at(id.length()-1) % 16;
     QString pathFragment = QString::number(code, 16) + QLatin1Char('/')

src/platformsupport/linuxaccessibility/atspiadaptor.cpp

@@ -1398,7 +1398,7 @@ bool AtSpiAdaptor::accessibleInterface(QAccessibleInterface *interface, const QS
         sendReply(connection, message, QVariant::fromValue(
                       QDBusVariant(QVariant::fromValue(QSpiObjectReference(connection, QDBusObjectPath(path))))));
     } else if (function == QLatin1String("GetChildAtIndex")) {
-        int index = message.arguments().first().toInt();
+        const int index = message.arguments().at(0).toInt();
         if (index < 0) {
             sendReply(connection, message, QVariant::fromValue(
                           QSpiObjectReference(connection, QDBusObjectPath(ATSPI_DBUS_PATH_NULL))));

src/tools/uic/main.cpp

@@ -115,7 +115,7 @@ int runUic(int argc, char *argv[])
 
     QString inputFile;
     if (!parser.positionalArguments().isEmpty())
-        inputFile = parser.positionalArguments().first();
+        inputFile = parser.positionalArguments().at(0);
     else // reading from stdin
         driver.option().headerProtection = false;
 

src/widgets/widgets/qcalendarwidget.cpp

@@ -765,7 +765,7 @@ bool QCalendarTextNavigator::eventFilter(QObject *o, QEvent *e)
     if (m_widget) {
         if (e->type() == QEvent::KeyPress || e->type() == QEvent::KeyRelease) {
             QKeyEvent* ke = (QKeyEvent*)e;
-            if ((ke->text().length() > 0 && ke->text()[0].isPrint()) || m_dateFrame) {
+            if ((ke->text().length() > 0 && ke->text().at(0).isPrint()) || m_dateFrame) {
                 if (ke->key() == Qt::Key_Return || ke->key() == Qt::Key_Enter || ke->key() == Qt::Key_Select) {
                     applyDate();
                     emit editingFinished();

src/widgets/widgets/qmenubar.cpp

@@ -1119,7 +1119,7 @@ void QMenuBar::keyPressEvent(QKeyEvent *e)
         int clashCount = 0;
         QAction *first = 0, *currentSelected = 0, *firstAfterCurrent = 0;
         {
-            QChar c = e->text()[0].toUpper();
+            const QChar c = e->text().at(0).toUpper();
             for(int i = 0; i < d->actions.size(); ++i) {
                 if (d->actionRects.at(i).isNull())
                     continue;