hyprland/focus_grab: handle destruction of tracked windows

Not supported by lld

.github/ISSUE_TEMPLATE/crash.yml

@@ -1,82 +1,17 @@
 name: Crash Report (v1)
-description: Quickshell has crashed
+description: Quickshell has crashed (old)
-labels: ["bug", "crash"]
+labels: ["unactionable"]
 body:
-  - type: textarea
+  - type: markdown
-    id: crashinfo
     attributes:
-      label: General crash information
+      value: |
-      description: |
+        Thank you for taking the time to click the report button.
-        Paste the contents of the `info.txt` file in your crash folder here.
+        At this point most of the worst issues in 0.2.1 and before have been fixed and we are
-      value: "<details> <summary>General information</summary>
+        preparing for a new release. Please do not submit this report.
-
+  - type: checkboxes
-
+    id: donotcheck
-        ```
+    attributes:
-
+      label: Read the text above. Do not submit the report.
-        <Paste the contents of the file here inside of the triple backticks>
+      options:
-
+        - label: Yes I want this report to be deleted.
-        ```
-
-
-        </details>"
-    validations:
           required: true
-  - type: textarea
-    id: userinfo
-    attributes:
-      label: What caused the crash
-      description: |
-        Any information likely to help debug the crash. What were you doing when the crash occurred,
-        what changes did you make, can you get it to happen again?
-  - type: textarea
-    id: dump
-    attributes:
-      label: Minidump
-      description: |
-        Attach `minidump.dmp.log` here. If it is too big to upload, compress it.
-
-        You may skip this step if quickshell crashed while processing a password
-        or other sensitive information. If you skipped it write why instead.
-    validations:
-        required: true
-  - type: textarea
-    id: logs
-    attributes:
-      label: Log file
-      description: |
-        Attach `log.qslog.log` here. If it is too big to upload, compress it.
-
-        You can preview the log if you'd like using `quickshell read-log <path-to-log>`.
-    validations:
-        required: true
-  - type: textarea
-    id: config
-    attributes:
-      label: Configuration
-      description: |
-        Attach your configuration here, preferrably in full (not just one file).
-        Compress it into a zip, tar, etc.
-
-        This will help us reproduce the crash ourselves.
-  - type: textarea
-    id: bt
-    attributes:
-      label: Backtrace
-      description: |
-        If you have gdb installed and use systemd, or otherwise know how to get a backtrace,
-        we would appreciate one. (You may have gdb installed without knowing it)
-
-        1. Run `coredumpctl debug <pid>` where `pid` is the number shown after "Crashed process ID"
-        in the crash reporter.
-        2. Once it loads, type `bt -full` (then enter)
-        3. Copy the output and attach it as a file or in a spoiler.
-  - type: textarea
-    id: exe
-    attributes:
-      label: Executable
-      description: |
-        If the crash folder contains a executable.txt file, upload it here. If not you can ignore this field.
-        If it is too big to upload, compress it.
-
-        Note: executable.txt is the quickshell binary. It has a .txt extension due to github's limitations on
-        filetypes.

.github/ISSUE_TEMPLATE/crash2.yml

@@ -9,21 +9,21 @@ body:
       description: |
         Any information likely to help debug the crash. What were you doing when the crash occurred,
         what changes did you make, can you get it to happen again?
-  - type: textarea
+  - type: upload
     id: report
     attributes:
       label: Report file
       description: Attach `report.txt` here.
     validations:
         required: true
-  - type: textarea
+  - type: upload
     id: logs
     attributes:
       label: Log file
       description: |
         Attach `log.qslog.log` here. If it is too big to upload, compress it.
 
-        You can preview the log if you'd like using `quickshell read-log <path-to-log>`.
+        You can preview the log if you'd like using `qs log <path-to-log> -r '*=true'`.
     validations:
         required: true
   - type: textarea
@@ -31,7 +31,7 @@ body:
     attributes:
       label: Configuration
       description: |
-        Attach your configuration here, preferrably in full (not just one file).
+        Attach or link your configuration here, preferrably in full (not just one file).
         Compress it into a zip, tar, etc.
 
         This will help us reproduce the crash ourselves.

changelog/next.md

@@ -48,6 +48,7 @@ set shell id.
 - Fixed volumes not initializing if a pipewire device was already loaded before its node.
 - Fixed hyprland active toplevel not resetting after window closes.
 - Fixed hyprland ipc window names and titles being reversed.
+- Fixed a hyprland ipc crash when refreshing toplevels before workspaces.
 - Fixed missing signals for system tray item title and description updates.
 - Fixed asynchronous loaders not working after reload.
 - Fixed asynchronous loaders not working before window creation.
@@ -58,6 +59,8 @@ set shell id.
 - Fixed ToplevelManager not clearing activeToplevel on deactivation.
 - Desktop action order is now preserved.
 - Fixed partial socket reads in greetd and hyprland on slow machines.
+- Worked around Qt bug causing crashes when plugging and unplugging monitors.
+- Fixed HyprlandFocusGrab crashing if windows were destroyed after being passed to it.
 
 ## Packaging Changes
 

src/core/logging.cpp

@@ -31,6 +31,9 @@
 #include <sys/sendfile.h>
 #include <sys/types.h>
 #endif
+#ifdef __FreeBSD__
+#include <unistd.h>
+#endif
 
 #include "instanceinfo.hpp"
 #include "logcat.hpp"
@@ -67,7 +70,7 @@ bool copyFileData(int sourceFd, int destFd, qint64 size) {
 	return true;
 #else
 	std::array<char, 64 * 1024> buffer = {};
-	auto remaining = totalTarget;
+	auto remaining = usize;
 
 	while (remaining > 0) {
 		auto chunk = std::min(remaining, buffer.size());

src/core/platformmenu.cpp

@@ -18,7 +18,6 @@
 #include <qwindow.h>
 
 #include "../window/proxywindow.hpp"
-#include "../window/windowinterface.hpp"
 #include "iconprovider.hpp"
 #include "model.hpp"
 #include "platformmenu_p.hpp"
@@ -91,10 +90,8 @@ bool PlatformMenuEntry::display(QObject* parentWindow, int relativeX, int relati
 	} else if (parentWindow == nullptr) {
 		qCritical() << "Cannot display PlatformMenuEntry with null parent window.";
 		return false;
-	} else if (auto* proxy = qobject_cast<ProxyWindowBase*>(parentWindow)) {
+	} else if (auto* proxy = ProxyWindowBase::forObject(parentWindow)) {
 		window = proxy->backingWindow();
-	} else if (auto* interface = qobject_cast<WindowInterface*>(parentWindow)) {
-		window = interface->proxyWindow()->backingWindow();
 	} else {
 		qCritical() << "PlatformMenuEntry.display() must be called with a window.";
 		return false;

src/core/popupanchor.cpp

@@ -11,7 +11,6 @@
 #include <qwindow.h>
 
 #include "../window/proxywindow.hpp"
-#include "../window/windowinterface.hpp"
 #include "types.hpp"
 
 bool PopupAnchorState::operator==(const PopupAnchorState& other) const {
@@ -40,10 +39,8 @@ void PopupAnchor::setWindowInternal(QObject* window) {
 	}
 
 	if (window) {
-		if (auto* proxy = qobject_cast<ProxyWindowBase*>(window)) {
+		if (auto* proxy = ProxyWindowBase::forObject(window)) {
 			this->bProxyWindow = proxy;
-		} else if (auto* interface = qobject_cast<WindowInterface*>(window)) {
-			this->bProxyWindow = interface->proxyWindow();
 		} else {
 			qWarning() << "Tried to set popup anchor window to" << window
 			           << "which is not a quickshell window.";

src/services/pam/conversation.cpp

@@ -8,6 +8,9 @@
 #include <qtmetamacros.h>
 #include <sys/signal.h>
 #include <sys/wait.h>
+#ifdef __FreeBSD__
+#include <signal.h>
+#endif
 
 #include "../../core/logcat.hpp"
 #include "ipc.hpp"

src/wayland/CMakeLists.txt

@@ -73,6 +73,7 @@ endfunction()
 # -----
 
 qt_add_library(quickshell-wayland STATIC
+	wl_proxy_safe_deref.cpp
 	platformmenu.cpp
 	popupanchor.cpp
 	xdgshell.cpp
@@ -80,6 +81,10 @@ qt_add_library(quickshell-wayland STATIC
 	output_tracking.cpp
 )
 
+# required for wl_proxy_safe_deref
+target_link_libraries(quickshell-wayland PRIVATE ${CMAKE_DL_LIBS})
+target_link_options(quickshell PRIVATE "LINKER:--export-dynamic-symbol=wl_proxy_get_listener")
+
 # required to make sure the constructor is linked
 add_library(quickshell-wayland-init OBJECT init.cpp)
 

src/wayland/hyprland/focus_grab/qml.cpp

@@ -9,7 +9,6 @@
 #include <qwindow.h>
 
 #include "../../../window/proxywindow.hpp"
-#include "../../../window/windowinterface.hpp"
 #include "grab.hpp"
 #include "manager.hpp"
 
@@ -38,8 +37,51 @@ QObjectList HyprlandFocusGrab::windows() const { return this->windowObjects; }
 
 void HyprlandFocusGrab::setWindows(QObjectList windows) {
 	if (windows == this->windowObjects) return;
+	if (this->grab) this->grab->startTransaction();
+
+	for (auto* obj: this->windowObjects) {
+		if (windows.contains(obj)) continue;
+		QObject::disconnect(obj, nullptr, this, nullptr);
+
+		auto* proxy = ProxyWindowBase::forObject(obj);
+		if (!proxy) continue;
+
+		QObject::disconnect(proxy, nullptr, this, nullptr);
+
+		if (this->grab && proxy->backingWindow()) {
+			this->grab->removeWindow(proxy->backingWindow());
+		}
+	}
+
+	for (auto it = windows.begin(); it != windows.end();) {
+		auto* proxy = ProxyWindowBase::forObject(*it);
+		if (!proxy) {
+			it = windows.erase(it);
+			continue;
+		}
+
+		if (this->windowObjects.contains(*it)) {
+			++it;
+			continue;
+		}
+
+		QObject::connect(*it, &QObject::destroyed, this, &HyprlandFocusGrab::onObjectDestroyed);
+		QObject::connect(
+		    proxy,
+		    &ProxyWindowBase::windowConnected,
+		    this,
+		    &HyprlandFocusGrab::onProxyConnected
+		);
+
+		if (this->grab && proxy->backingWindow()) {
+			this->grab->addWindow(proxy->backingWindow());
+		}
+
+		++it;
+	}
+
+	if (this->grab) this->grab->completeTransaction();
 	this->windowObjects = std::move(windows);
-	this->syncWindows();
 	emit this->windowsChanged();
 }
 
@@ -75,59 +117,18 @@ void HyprlandFocusGrab::tryActivate() {
 	QObject::connect(this->grab, &FocusGrab::cleared, this, &HyprlandFocusGrab::onGrabCleared);
 
 	this->grab->startTransaction();
-	for (auto* proxy: this->trackedProxies) {
+	for (auto* obj: this->windowObjects) {
-		if (proxy->backingWindow() != nullptr) {
+		auto* proxy = ProxyWindowBase::forObject(obj);
+		if (proxy && proxy->backingWindow()) {
 			this->grab->addWindow(proxy->backingWindow());
 		}
 	}
 	this->grab->completeTransaction();
 }
 
-void HyprlandFocusGrab::syncWindows() {
+void HyprlandFocusGrab::onObjectDestroyed(QObject* object) {
-	auto newProxy = QList<ProxyWindowBase*>();
+	this->windowObjects.removeOne(object);
-	for (auto* windowObject: this->windowObjects) {
+	emit this->windowsChanged();
-		auto* proxyWindow = qobject_cast<ProxyWindowBase*>(windowObject);
-
-		if (proxyWindow == nullptr) {
-			if (auto* iface = qobject_cast<WindowInterface*>(windowObject)) {
-				proxyWindow = iface->proxyWindow();
-			}
-		}
-
-		if (proxyWindow != nullptr) {
-			newProxy.push_back(proxyWindow);
-		}
-	}
-
-	if (this->grab) this->grab->startTransaction();
-
-	for (auto* oldWindow: this->trackedProxies) {
-		if (!newProxy.contains(oldWindow)) {
-			QObject::disconnect(oldWindow, nullptr, this, nullptr);
-
-			if (this->grab != nullptr && oldWindow->backingWindow() != nullptr) {
-				this->grab->removeWindow(oldWindow->backingWindow());
-			}
-		}
-	}
-
-	for (auto* newProxy: newProxy) {
-		if (!this->trackedProxies.contains(newProxy)) {
-			QObject::connect(
-			    newProxy,
-			    &ProxyWindowBase::windowConnected,
-			    this,
-			    &HyprlandFocusGrab::onProxyConnected
-			);
-
-			if (this->grab != nullptr && newProxy->backingWindow() != nullptr) {
-				this->grab->addWindow(newProxy->backingWindow());
-			}
-		}
-	}
-
-	this->trackedProxies = newProxy;
-	if (this->grab) this->grab->completeTransaction();
 }
 
 } // namespace qs::hyprland

src/wayland/hyprland/focus_grab/qml.hpp

@@ -96,15 +96,13 @@ private slots:
 	void onGrabActivated();
 	void onGrabCleared();
 	void onProxyConnected();
+	void onObjectDestroyed(QObject* object);
 
 private:
 	void tryActivate();
-	void syncWindows();
 
 	bool targetActive = false;
 	QObjectList windowObjects;
-	QList<ProxyWindowBase*> trackedProxies;
-	QList<QWindow*> trackedWindows;
 
 	focus_grab::FocusGrab* grab = nullptr;
 };

src/wayland/hyprland/ipc/connection.cpp

@@ -729,7 +729,7 @@ void HyprlandIpc::refreshToplevels() {
 			}
 
 			auto* workspace = toplevel->bindableWorkspace().value();
-			workspace->insertToplevel(toplevel);
+			if (workspace) workspace->insertToplevel(toplevel);
 		}
 	});
 }

src/wayland/hyprland/ipc/hyprland_toplevel.cpp

@@ -72,20 +72,16 @@ void HyprlandToplevel::updateFromObject(const QVariantMap& object) {
 	Qt::beginPropertyUpdateGroup();
 	bool ok = false;
 	auto address = addressStr.toULongLong(&ok, 16);
-	if (!ok || !address) {
+	if (ok && address) this->setAddress(address);
-		return;
-	}
 
-	this->setAddress(address);
 	this->bTitle = title;
 
 	auto workspaceMap = object.value("workspace").toMap();
 	auto workspaceName = workspaceMap.value("name").toString();
 
-	auto* workspace = this->ipc->findWorkspaceByName(workspaceName, false);
+	auto* workspace = this->ipc->findWorkspaceByName(workspaceName, true);
-	if (!workspace) return;
+	if (workspace) this->setWorkspace(workspace);
 
-	this->setWorkspace(workspace);
 	this->bLastIpcObject = object;
 	Qt::endPropertyUpdateGroup();
 }

src/wayland/hyprland/surface/qml.cpp

@@ -14,7 +14,6 @@
 
 #include "../../../core/region.hpp"
 #include "../../../window/proxywindow.hpp"
-#include "../../../window/windowinterface.hpp"
 #include "manager.hpp"
 #include "surface.hpp"
 
@@ -23,13 +22,7 @@ using QtWaylandClient::QWaylandWindow;
 namespace qs::hyprland::surface {
 
 HyprlandWindow* HyprlandWindow::qmlAttachedProperties(QObject* object) {
-	auto* proxyWindow = qobject_cast<ProxyWindowBase*>(object);
+	auto* proxyWindow = ProxyWindowBase::forObject(object);
-
-	if (!proxyWindow) {
-		if (auto* iface = qobject_cast<WindowInterface*>(object)) {
-			proxyWindow = iface->proxyWindow();
-		}
-	}
 
 	if (!proxyWindow) return nullptr;
 	return new HyprlandWindow(proxyWindow);

src/wayland/idle_inhibit/inhibitor.cpp

@@ -6,7 +6,6 @@
 #include <qtmetamacros.h>
 
 #include "../../window/proxywindow.hpp"
-#include "../../window/windowinterface.hpp"
 #include "proto.hpp"
 
 namespace qs::wayland::idle_inhibit {
@@ -25,27 +24,13 @@ QObject* IdleInhibitor::window() const { return this->bWindowObject; }
 void IdleInhibitor::setWindow(QObject* window) {
 	if (window == this->bWindowObject) return;
 
-	auto* proxyWindow = qobject_cast<ProxyWindowBase*>(window);
+	auto* proxyWindow = ProxyWindowBase::forObject(window);
-
-	if (proxyWindow == nullptr) {
-		if (auto* iface = qobject_cast<WindowInterface*>(window)) {
-			proxyWindow = iface->proxyWindow();
-		}
-	}
-
 	this->bWindowObject = proxyWindow ? window : nullptr;
 }
 
 void IdleInhibitor::boundWindowChanged() {
 	auto* window = this->bBoundWindow.value();
-	auto* proxyWindow = qobject_cast<ProxyWindowBase*>(window);
+	auto* proxyWindow = ProxyWindowBase::forObject(window);
-
-	if (proxyWindow == nullptr) {
-		if (auto* iface = qobject_cast<WindowInterface*>(window)) {
-			proxyWindow = iface->proxyWindow();
-		}
-	}
-
 	if (proxyWindow == this->proxyWindow) return;
 
 	if (this->mWaylandWindow) {

src/wayland/init.cpp

@@ -10,6 +10,7 @@
 #include "wlr_layershell/wlr_layershell.hpp"
 #endif
 
+void installWlProxySafeDeref(); // NOLINT(misc-use-internal-linkage)
 void installPlatformMenuHook(); // NOLINT(misc-use-internal-linkage)
 void installPopupPositioner();  // NOLINT(misc-use-internal-linkage)
 
@@ -33,6 +34,7 @@ class WaylandPlugin: public QsEnginePlugin {
 	}
 
 	void init() override {
+		installWlProxySafeDeref();
 		installPlatformMenuHook();
 		installPopupPositioner();
 	}

src/wayland/shortcuts_inhibit/inhibitor.cpp

@@ -9,7 +9,6 @@
 #include <qwindow.h>
 
 #include "../../window/proxywindow.hpp"
-#include "../../window/windowinterface.hpp"
 #include "proto.hpp"
 
 namespace qs::wayland::shortcuts_inhibit {
@@ -48,14 +47,7 @@ ShortcutInhibitor::~ShortcutInhibitor() {
 
 void ShortcutInhibitor::onBoundWindowChanged() {
 	auto* window = this->bBoundWindow.value();
-	auto* proxyWindow = qobject_cast<ProxyWindowBase*>(window);
+	auto* proxyWindow = ProxyWindowBase::forObject(window);
-
-	if (!proxyWindow) {
-		if (auto* iface = qobject_cast<WindowInterface*>(window)) {
-			proxyWindow = iface->proxyWindow();
-		}
-	}
-
 	if (proxyWindow == this->proxyWindow) return;
 
 	if (this->proxyWindow) {

src/wayland/toplevel_management/qml.cpp

@@ -9,7 +9,6 @@
 #include "../../core/qmlscreen.hpp"
 #include "../../core/util.hpp"
 #include "../../window/proxywindow.hpp"
-#include "../../window/windowinterface.hpp"
 #include "../output_tracking.hpp"
 #include "handle.hpp"
 #include "manager.hpp"
@@ -73,13 +72,7 @@ void Toplevel::fullscreenOn(QuickshellScreenInfo* screen) {
 }
 
 void Toplevel::setRectangle(QObject* window, QRect rect) {
-	auto* proxyWindow = qobject_cast<ProxyWindowBase*>(window);
+	auto* proxyWindow = ProxyWindowBase::forObject(window);
-
-	if (proxyWindow == nullptr) {
-		if (auto* iface = qobject_cast<WindowInterface*>(window)) {
-			proxyWindow = iface->proxyWindow();
-		}
-	}
 
 	if (proxyWindow != this->rectWindow) {
 		if (this->rectWindow != nullptr) {

src/wayland/windowmanager/windowset.cpp

@@ -8,9 +8,9 @@
 #include <qobjectdefs.h>
 #include <qproperty.h>
 
+#include "../../windowmanager/screenprojection.hpp"
 #include "../../windowmanager/windowmanager.hpp"
 #include "../../windowmanager/windowset.hpp"
-#include "../../windowmanager/screenprojection.hpp"
 #include "ext_workspace.hpp"
 
 namespace qs::wm::wayland {

src/wayland/wl_proxy_safe_deref.cpp

@@ -0,0 +1,41 @@
+#include <dlfcn.h>
+#include <qlogging.h>
+#include <qloggingcategory.h>
+#include <wayland-client-core.h>
+#include <wayland-util.h>
+
+#include "../core/logcat.hpp"
+
+namespace {
+QS_LOGGING_CATEGORY(logDeref, "quickshell.wayland.safederef", QtWarningMsg);
+using wl_proxy_get_listener_t = const void* (*) (wl_proxy*);
+wl_proxy_get_listener_t original_wl_proxy_get_listener = nullptr; // NOLINT
+} // namespace
+
+extern "C" {
+WL_EXPORT const void* wl_proxy_get_listener(struct wl_proxy* proxy) {
+	// Avoid null derefs of protocol objects in qtbase.
+	// https://qt-project.atlassian.net/browse/QTBUG-145022
+	if (!proxy) [[unlikely]] {
+		qCCritical(logDeref) << "wl_proxy_get_listener called with a null proxy!";
+		return nullptr;
+	}
+
+	return original_wl_proxy_get_listener(proxy);
+}
+}
+
+// NOLINTBEGIN (concurrency-mt-unsafe)
+void installWlProxySafeDeref() {
+	dlerror(); // clear old errors
+
+	original_wl_proxy_get_listener =
+	    reinterpret_cast<wl_proxy_get_listener_t>(dlsym(RTLD_NEXT, "wl_proxy_get_listener"));
+
+	if (auto* error = dlerror()) {
+		qCCritical(logDeref) << "Failed to find wl_proxy_get_listener for hooking:" << error;
+	} else {
+		qCInfo(logDeref) << "Installed wl_proxy_get_listener hook.";
+	}
+}
+// NOLINTEND

src/wayland/wlr_layershell/surface.cpp

@@ -17,6 +17,7 @@
 #include <qvariant.h>
 #include <qwayland-wlr-layer-shell-unstable-v1.h>
 #include <qwindow.h>
+#include <wayland-xdg-shell-client-protocol.h>
 
 #include "../../window/panelinterface.hpp"
 #include "shell_integration.hpp"
@@ -247,9 +248,19 @@ void LayerSurface::commit() {
 }
 
 void LayerSurface::attachPopup(QtWaylandClient::QWaylandShellSurface* popup) {
-	std::any role = popup->surfaceRole();
+#ifdef __FreeBSD__
-
+	// FreeBSD uses an alternate RTTI matching strategy by default which does
-	if (auto* popupRole = std::any_cast<::xdg_popup*>(&role)) { // NOLINT
+	// not work across modules, preventing std::any from downcasting. On
+	// FreeBSD, Qt is built with a patch to expose the surface role through a
+	// pointer instead of an any, which does not have this problem.
+	// See https://bugs.kde.org/show_bug.cgi?id=479679
+	if (auto* xdgPopup = static_cast<::xdg_popup*>(popup->nativeResource("xdg_popup"))) {
+		this->get_popup(xdgPopup);
+		return;
+	}
+#endif
+	auto role = popup->surfaceRole(); // NOLINT
+	if (auto* popupRole = std::any_cast<::xdg_popup*>(&role)) {
 		this->get_popup(*popupRole);
 	} else {
 		qWarning() << "Cannot attach popup" << popup << "to shell surface" << this

src/window/proxywindow.cpp

@@ -57,6 +57,12 @@ ProxyWindowBase::ProxyWindowBase(QObject* parent)
 
 ProxyWindowBase::~ProxyWindowBase() { this->deleteWindow(true); }
 
+ProxyWindowBase* ProxyWindowBase::forObject(QObject* obj) {
+	if (auto* proxy = qobject_cast<ProxyWindowBase*>(obj)) return proxy;
+	if (auto* iface = qobject_cast<WindowInterface*>(obj)) return iface->proxyWindow();
+	return nullptr;
+}
+
 void ProxyWindowBase::onReload(QObject* oldInstance) {
 	if (this->mVisible) this->window = this->retrieveWindow(oldInstance);
 	auto wasVisible = this->window != nullptr && this->window->isVisible();

src/window/proxywindow.hpp

@@ -66,6 +66,8 @@ public:
 	explicit ProxyWindowBase(QObject* parent = nullptr);
 	~ProxyWindowBase() override;
 
+	static ProxyWindowBase* forObject(QObject* obj);
+
 	ProxyWindowBase(ProxyWindowBase&) = delete;
 	ProxyWindowBase(ProxyWindowBase&&) = delete;
 	void operator=(ProxyWindowBase&) = delete;