Don't initialize QFlags<T> with nullptr

Summary: This looks very odd.

Test Plan: Compiles.

Reviewers: #kwin, romangg

Reviewed By: #kwin, romangg

Subscribers: apol, kwin

Tags: #kwin

Differential Revision: https://phabricator.kde.org/D24086

client.cpp

@@ -116,7 +116,7 @@ Client::Client()
     , m_killHelperPID(0)
     , m_pingTimestamp(XCB_TIME_CURRENT_TIME)
     , m_userTime(XCB_TIME_CURRENT_TIME)   // Not known yet
-    , allowed_actions(nullptr)
+    , allowed_actions()
     , shade_geometry_change(false)
     , sm_stacking_order(-1)
     , activitiesDefined(false)
@@ -1768,7 +1768,7 @@ void Client::updateAllowedActions(bool force)
     if (!isManaged() && !force)
         return;
     NET::Actions old_allowed_actions = NET::Actions(allowed_actions);
-    allowed_actions = nullptr;
+    allowed_actions = NET::Actions();
     if (isMovable())
         allowed_actions |= NET::ActionMove;
     if (isResizable())

effects/desktopgrid/desktopgrid_config.cpp

@@ -73,7 +73,7 @@ DesktopGridEffectConfig::DesktopGridEffectConfig(QWidget* parent, const QVariant
     m_ui->shortcutEditor->addCollection(m_actionCollection);
 
 
-    m_ui->desktopNameAlignmentCombo->addItem(i18nc("Desktop name alignment:", "Disabled"), QVariant(Qt::Alignment(nullptr)));
+    m_ui->desktopNameAlignmentCombo->addItem(i18nc("Desktop name alignment:", "Disabled"), QVariant(Qt::Alignment()));
     m_ui->desktopNameAlignmentCombo->addItem(i18n("Top"), QVariant(Qt::AlignHCenter | Qt::AlignTop));
     m_ui->desktopNameAlignmentCombo->addItem(i18n("Top-Right"), QVariant(Qt::AlignRight | Qt::AlignTop));
     m_ui->desktopNameAlignmentCombo->addItem(i18n("Right"), QVariant(Qt::AlignRight | Qt::AlignVCenter));

effects/trackmouse/trackmouse.cpp

@@ -83,7 +83,7 @@ TrackMouseEffect::~TrackMouseEffect()
 
 void TrackMouseEffect::reconfigure(ReconfigureFlags)
 {
-    m_modifiers = nullptr;
+    m_modifiers = Qt::KeyboardModifiers();
     TrackMouseConfig::self()->read();
     if (TrackMouseConfig::shift())
         m_modifiers |= Qt::ShiftModifier;

events.cpp

@@ -444,7 +444,7 @@ bool Client::windowEvent(xcb_generic_event_t *e)
                 emit opacityChanged(this, old_opacity);
             } else {
                 // forward to the frame if there's possibly another compositing manager running
-                NETWinInfo i(connection(), frameId(), rootWindow(), nullptr, nullptr);
+                NETWinInfo i(connection(), frameId(), rootWindow(), NET::Properties(), NET::Properties2());
                 i.setOpacity(info->opacity());
             }
         }

geometry.cpp

@@ -894,7 +894,7 @@ void Workspace::setMoveResizeClient(AbstractClient *c)
 // (the property with the size of the frame remains on the window after the crash).
 void Workspace::fixPositionAfterCrash(xcb_window_t w, const xcb_get_geometry_reply_t *geometry)
 {
-    NETWinInfo i(connection(), w, rootWindow(), NET::WMFrameExtents, nullptr);
+    NETWinInfo i(connection(), w, rootWindow(), NET::WMFrameExtents, NET::Properties2());
     NETStrut frame = i.frameExtents();
 
     if (frame.left != 0 || frame.top != 0) {

group.cpp

@@ -60,7 +60,7 @@ Group::Group(xcb_window_t leader_P)
     if (leader_P != XCB_WINDOW_NONE) {
         leader_client = workspace()->findClient(Predicate::WindowMatch, leader_P);
         leader_info = new NETWinInfo(connection(), leader_P, rootWindow(),
-                                      nullptr, NET::WM2StartupId);
+                                     NET::Properties(), NET::WM2StartupId);
     }
     effect_group = new EffectWindowGroupImpl(this);
     workspace()->addGroup(this);

kcmkwin/kwinrules/ruleswidget.cpp

@@ -586,7 +586,7 @@ Rules* RulesWidget::rules() const
     rules->wmclassmatch = static_cast< Rules::StringMatch >(wmclass_match->currentIndex());
     rules->windowrole = role->text().toUtf8();
     rules->windowrolematch = static_cast< Rules::StringMatch >(role_match->currentIndex());
-    rules->types = nullptr;
+    rules->types = {};
     bool all_types = true;
     for (int i = 0;
             i < types->count();

manage.cpp

@@ -606,7 +606,7 @@ bool Client::manage(xcb_window_t w, bool isMapped)
             if (opacity() == 1.0) {
                 return;
             }
-            NETWinInfo info(connection(), frameId(), rootWindow(), nullptr, nullptr);
+            NETWinInfo info(connection(), frameId(), rootWindow(), NET::Properties(), NET::Properties2());
             info.setOpacity(static_cast<unsigned long>(opacity() * 0xffffffff));
         }
     );

utils.cpp

@@ -172,7 +172,7 @@ Qt::MouseButton x11ToQtMouseButton(int button)
 
 Qt::MouseButtons x11ToQtMouseButtons(int state)
 {
-    Qt::MouseButtons ret = nullptr;
+    Qt::MouseButtons ret = {};
     if (state & XCB_KEY_BUT_MASK_BUTTON_1)
         ret |= Qt::LeftButton;
     if (state & XCB_KEY_BUT_MASK_BUTTON_2)
@@ -188,7 +188,7 @@ Qt::MouseButtons x11ToQtMouseButtons(int state)
 
 Qt::KeyboardModifiers x11ToQtKeyboardModifiers(int state)
 {
-    Qt::KeyboardModifiers ret = nullptr;
+    Qt::KeyboardModifiers ret = {};
     if (state & XCB_KEY_BUT_MASK_SHIFT)
         ret |= Qt::ShiftModifier;
     if (state & XCB_KEY_BUT_MASK_CONTROL)