diff --git a/src/applib/app_builder_widget.h b/src/applib/app_builder_widget.h
index 9077ee3..228624a 100644
--- a/src/applib/app_builder_widget.h
+++ b/src/applib/app_builder_widget.h
@@ -64,13 +64,13 @@ class AppBuilderWidget : public WidgetType, public WindowInstanceManager<Child,
 		AppBuilderWidget(const AppBuilderWidget& other) = delete;
 
 		/// Disallow
-		AppBuilderWidget(const AppBuilderWidget&& other) = delete;
+		AppBuilderWidget(AppBuilderWidget&& other) = delete;
 
 		/// Disallow
 		AppBuilderWidget& operator=(const AppBuilderWidget& other) = delete;
 
 		/// Disallow
-		AppBuilderWidget& operator=(const AppBuilderWidget&& other) = delete;
+		AppBuilderWidget& operator=(AppBuilderWidget&& other) = delete;
 
 		/// Default
 		~AppBuilderWidget() = default;
diff --git a/src/applib/app_gtkmm_tools.cpp b/src/applib/app_gtkmm_tools.cpp
index 9b917e6..b586599 100644
--- a/src/applib/app_gtkmm_tools.cpp
+++ b/src/applib/app_gtkmm_tools.cpp
@@ -110,7 +110,7 @@ namespace {
 Glib::ustring app_ustring_from_gchar(gchar* str)
 {
 	if (!str) {
-		return Glib::ustring();
+		return {};
 	}
 	Glib::ustring ustr(str);
 	g_free(str);
diff --git a/src/applib/async_command_executor.h b/src/applib/async_command_executor.h
index 57226aa..141b717 100644
--- a/src/applib/async_command_executor.h
+++ b/src/applib/async_command_executor.h
@@ -39,13 +39,13 @@ class AsyncCommandExecutor : public hz::ErrorHolder {
 		AsyncCommandExecutor(const AsyncCommandExecutor& other) = delete;
 
 		/// Deleted
-		AsyncCommandExecutor(const AsyncCommandExecutor&& other) = delete;
+		AsyncCommandExecutor(AsyncCommandExecutor&& other) = delete;
 
 		/// Deleted
 		AsyncCommandExecutor& operator=(const AsyncCommandExecutor& other) = delete;
 
 		/// Deleted
-		AsyncCommandExecutor& operator=(const AsyncCommandExecutor&& other) = delete;
+		AsyncCommandExecutor& operator=(AsyncCommandExecutor&& other) = delete;
 
 
 		/// Destructor. Don't destroy this object unless the child has exited. It will leak stuff
@@ -196,8 +196,8 @@ class AsyncCommandExecutor : public hz::ErrorHolder {
 		GIOChannel* channel_stdout_ = nullptr;  ///< stdout channel
 		GIOChannel* channel_stderr_ = nullptr;  ///< stderr channel
 
-		gsize channel_stdout_buffer_size_ = 100 * 1024;  ///< stdout channel buffer size. NOT affected by cleanup_members(). 100K.
-		gsize channel_stderr_buffer_size_ = 10 * 1024;  ///< stderr channel buffer size. NOT affected by cleanup_members(). 10K.
+		gsize channel_stdout_buffer_size_ = 100UL * 1024UL;  ///< stdout channel buffer size. NOT affected by cleanup_members(). 100K.
+		gsize channel_stderr_buffer_size_ = 10UL * 1024UL;  ///< stderr channel buffer size. NOT affected by cleanup_members(). 10K.
 
 		guint event_source_id_stdout_ = 0;  ///< IO watcher event source ID for stdout
 		guint event_source_id_stderr_ = 0;  ///< IO watcher event source ID for stderr
diff --git a/src/applib/ata_storage_property_descr.cpp b/src/applib/ata_storage_property_descr.cpp
index 454aa42..daf1651 100644
--- a/src/applib/ata_storage_property_descr.cpp
+++ b/src/applib/ata_storage_property_descr.cpp
@@ -1110,11 +1110,11 @@ namespace {
 				// search by ID first
 				auto id_iter = id_db.find(id);
 				if (id_iter == id_db.end()) {
-					return AttributeDescription();  // not found
+					return {};  // not found
 				}
 				DBG_ASSERT(!id_iter->second.empty());
 				if (id_iter->second.empty()) {
-					return AttributeDescription();  // invalid DB?
+					return {};  // invalid DB?
 				}
 
 				std::vector<AttributeDescription> type_matched;
@@ -1124,7 +1124,7 @@ namespace {
 					}
 				}
 				if (type_matched.empty()) {
-					return AttributeDescription();  // not found
+					return {};  // not found
 				}
 
 				// search by smartctl name in ID-supplied vector
@@ -1371,7 +1371,7 @@ namespace {
 				// search by ID first
 				auto iter = devstat_db.find(reported_name);
 				if (iter == devstat_db.end()) {
-					return StatisticDescription();  // not found
+					return {};  // not found
 				}
 				return iter->second;
 			}
diff --git a/src/applib/command_executor.cpp b/src/applib/command_executor.cpp
index 0adeaad..f503b5a 100644
--- a/src/applib/command_executor.cpp
+++ b/src/applib/command_executor.cpp
@@ -34,9 +34,9 @@ CommandExecutor::CommandExecutor(std::string command_name, std::string command_a
 
 
 CommandExecutor::CommandExecutor()
+		// Translators: {command} will be replaced by command name.
+		: running_msg_(_("Running {command}..."))
 {
-	/// Translators: {command} will be replaced by command name.
-	running_msg_ = _("Running {command}...");
 	set_error_header(std::string(_("An error occurred while executing command:")) + "\n\n");
 }
 
@@ -131,7 +131,7 @@ bool CommandExecutor::execute()
 			g_main_context_iteration(nullptr, FALSE);
 		}
 
-		const gulong sleep_us = 50*1000;  // 50 msec. avoids 100% CPU usage.
+		const gulong sleep_us = 50UL * 1000UL;  // 50 msec. avoids 100% CPU usage.
 		g_usleep(sleep_us);
 	}
 
diff --git a/src/applib/command_executor.h b/src/applib/command_executor.h
index 64ddb0b..cb02333 100644
--- a/src/applib/command_executor.h
+++ b/src/applib/command_executor.h
@@ -70,13 +70,13 @@ class CommandExecutor : public sigc::trackable {
 		CommandExecutor(const CommandExecutor& other) = delete;
 
 		/// Deleted
-		CommandExecutor(const CommandExecutor&& other) = delete;
+		CommandExecutor(CommandExecutor&& other) = delete;
 
 		/// Deleted
 		CommandExecutor& operator=(CommandExecutor& other) = delete;
 
 		/// Deleted
-		CommandExecutor& operator=(const CommandExecutor&& other) = delete;
+		CommandExecutor& operator=(CommandExecutor&& other) = delete;
 
 
 		/// Virtual destructor
diff --git a/src/applib/gui_utils.h b/src/applib/gui_utils.h
index 0d7acd7..2140285 100644
--- a/src/applib/gui_utils.h
+++ b/src/applib/gui_utils.h
@@ -55,7 +55,7 @@ bool gui_show_text_entry_dialog(const std::string& title, const std::string& mes
 /// \c result is filled with the user-entered string on success.
 /// \return false if Cancel was clicked.
 bool gui_show_text_entry_dialog(const std::string& title, const std::string& message, const std::string& sec_message,
-		std::string& result, const std::string& default_str, Gtk::Window* parent = 0, bool sec_msg_markup = false);
+		std::string& result, const std::string& default_str, Gtk::Window* parent = nullptr, bool sec_msg_markup = false);
 
 
 
diff --git a/src/applib/selftest.cpp b/src/applib/selftest.cpp
index a3aab27..d12ce24 100644
--- a/src/applib/selftest.cpp
+++ b/src/applib/selftest.cpp
@@ -89,14 +89,12 @@ bool SelfTest::is_supported() const
 	if (!drive_)
 		return false;
 
-	if (type_ == TestType::immediate_offline)  // disable this for now - it's unsupported.
-		return false;
-
 	std::string prop_name;
 	switch(type_) {
 		case TestType::immediate_offline:
-			prop_name = "iodc_support";
-			break;
+			// prop_name = "iodc_support";
+			// break;
+			return false;  // disable this for now - it's unsupported.
 		case TestType::short_test:
 		case TestType::long_test:  // same for short and long
 			prop_name = "selftest_support";
@@ -168,7 +166,7 @@ std::string SelfTest::start(const std::shared_ptr<CommandExecutor>& smartctl_ex)
 	drive_->set_test_is_active(true);
 
 
-	return std::string();  // everything ok
+	return {};  // everything ok
 }
 
 
@@ -221,7 +219,7 @@ std::string SelfTest::force_stop(const std::shared_ptr<CommandExecutor>& smartct
 
 	if (!error_msg.empty())  // update can error out too.
 		return error_msg;
-	return std::string();  // everything ok
+	return {};  // everything ok
 }
 
 
@@ -309,7 +307,7 @@ std::string SelfTest::update(const std::shared_ptr<CommandExecutor>& smartctl_ex
 
 	drive_->set_test_is_active(active);
 
-	return std::string();  // everything ok
+	return {};  // everything ok
 }
 
 
diff --git a/src/applib/smartctl_ata_text_parser.cpp b/src/applib/smartctl_ata_text_parser.cpp
index 6506a1e..a2cb736 100644
--- a/src/applib/smartctl_ata_text_parser.cpp
+++ b/src/applib/smartctl_ata_text_parser.cpp
@@ -365,7 +365,7 @@ std::string SmartctlAtaTextParser::parse_byte_size(const std::string& str, int64
 				" [" + hz::format_size(static_cast<uint64_t>(v), false) + ", " + hz::number_to_string_locale(v) + " bytes]" : "");
 	}
 
-	return std::string();
+	return {};
 }
 
 
diff --git a/src/applib/smartctl_executor.cpp b/src/applib/smartctl_executor.cpp
index c40f99a..11369cc 100644
--- a/src/applib/smartctl_executor.cpp
+++ b/src/applib/smartctl_executor.cpp
@@ -129,7 +129,7 @@ std::string execute_smartctl(const std::string& device, const std::string& devic
 		return _("Smartctl returned an empty output.");
 	}
 
-	return std::string();
+	return {};
 }
 
 
diff --git a/src/applib/storage_detector_helpers.h b/src/applib/storage_detector_helpers.h
index 482760f..7aab8cb 100644
--- a/src/applib/storage_detector_helpers.h
+++ b/src/applib/storage_detector_helpers.h
@@ -65,7 +65,7 @@ inline std::string execute_tw_cli(const CommandExecutorFactoryPtr& ex_factory, c
 		return _("tw_cli returned an empty output.");
 	}
 
-	return std::string();
+	return {};
 }
 
 
@@ -107,7 +107,7 @@ inline std::string tw_cli_get_drives(const std::string& dev, int controller,
 		}
 	}
 
-	return std::string();
+	return {};
 }
 
 
@@ -144,7 +144,7 @@ inline std::string tw_cli_get_controllers(const CommandExecutorFactoryPtr& ex_fa
 	// are sorted in the end anyway.
 	std::sort(controllers.begin(), controllers.end());
 
-	return std::string();
+	return {};
 }
 
 
@@ -191,7 +191,7 @@ inline std::string smartctl_scan_drives_sequentially(const std::string& dev, con
 		}
 	}
 
-	return std::string();
+	return {};
 }
 
 
diff --git a/src/applib/storage_detector_linux.cpp b/src/applib/storage_detector_linux.cpp
index 93bbc2b..dfab28d 100644
--- a/src/applib/storage_detector_linux.cpp
+++ b/src/applib/storage_detector_linux.cpp
@@ -143,7 +143,7 @@ inline std::error_code read_proc_file(const hz::fs::path& file, std::string& con
 	auto& cache = get_read_file_cache_ref();
 	if (auto iter = cache.find(file); iter != cache.end()) {
 		contents = iter->second;
-		return std::error_code();
+		return {};
 	}
 
 	auto ec = hz::fs_file_get_contents_unseekable(file, contents);
@@ -157,7 +157,7 @@ inline std::error_code read_proc_file(const hz::fs::path& file, std::string& con
 	debug_out_dump("app", DBG_FUNC_MSG << "File contents (\"" << file.string() << "\"):\n" << contents << "\n");
 	debug_end();
 
-	return std::error_code();
+	return {};
 }
 
 
@@ -196,7 +196,7 @@ inline std::string read_proc_partitions_file(std::vector<std::string>& lines)
 		return ec.message();
 	}
 
-	return std::string();
+	return {};
 }
 
 
@@ -221,7 +221,7 @@ inline std::string read_proc_devices_file(std::vector<std::string>& lines)
 		return ec.message();
 	}
 
-	return std::string();
+	return {};
 }
 
 
@@ -267,7 +267,7 @@ inline std::string read_proc_scsi_scsi_file(std::vector< std::pair<int, std::str
 		}
 	}
 
-	return std::string();
+	return {};
 }
 
 
@@ -315,7 +315,7 @@ inline std::string read_proc_scsi_sg_devices_file(std::vector<std::vector<int>>&
 		}
 	}
 
-	return std::string();
+	return {};
 }
 
 
@@ -434,7 +434,7 @@ inline std::string detect_drives_linux_proc_partitions(std::vector<StorageDevice
 		}
 	}
 
-	return std::string();
+	return {};
 }
 
 
@@ -499,7 +499,7 @@ inline std::string detect_drives_linux_3ware(std::vector<StorageDevicePtr>& driv
 
 	if (!twa_found && !twe_found && !twl_found) {
 		debug_out_info("app", DBG_FUNC_MSG << "No 3ware-specific entries found in devices file.\n");
-		return std::string();  // no controllers
+		return {};  // no controllers
 	}
 
 	lines.clear();
@@ -621,7 +621,7 @@ inline std::string detect_drives_linux_adaptec(std::vector<StorageDevicePtr>& dr
 	}
 	if (!aac_found) {
 		debug_out_info("app", DBG_FUNC_MSG << "No Adaptec-specific entries found in devices file.\n");
-		return std::string();  // no controllers
+		return {};  // no controllers
 	}
 
 	lines.clear();
@@ -903,7 +903,7 @@ inline std::string detect_drives_linux_cciss(std::vector<StorageDevicePtr>& driv
 	}
 	if (controllers.empty()) {
 		debug_out_info("app", DBG_FUNC_MSG << "No cciss-specific entries found in devices file.\n");
-		return std::string();  // no controllers
+		return {};  // no controllers
 	}
 
 	std::shared_ptr<CommandExecutor> smartctl_ex = ex_factory->create_executor(CommandExecutorFactory::ExecutorType::Smartctl);
diff --git a/src/applib/storage_device.cpp b/src/applib/storage_device.cpp
index b17ca9f..ff26f3b 100644
--- a/src/applib/storage_device.cpp
+++ b/src/applib/storage_device.cpp
@@ -59,10 +59,9 @@ std::string StorageDevice::get_status_displayable_name(Status status)
 
 
 StorageDevice::StorageDevice(std::string dev_or_vfile, bool is_virtual)
+		: is_virtual_(is_virtual)
 {
-	is_virtual_ = is_virtual;
-
-	if (is_virtual) {
+	if (is_virtual_) {
 		virtual_file_ = hz::fs::u8path(dev_or_vfile);
 	} else {
 		device_ = std::move(dev_or_vfile);
@@ -249,7 +248,7 @@ std::string StorageDevice::parse_basic_data(bool do_set_properties, bool emit_si
 	if (emit_signal)
 		signal_changed().emit(this);  // notify listeners
 
-	return std::string();
+	return {};
 }
 
 
@@ -320,7 +319,7 @@ std::string StorageDevice::parse_data()
 
 		signal_changed().emit(this);  // notify listeners
 
-		return std::string();
+		return {};
 	}
 
 	// Don't show any GUI warnings on parse failure - it may just be an unsupported
@@ -334,7 +333,7 @@ std::string StorageDevice::parse_data()
 		return ps.get_error_msg();  // return full parser's error messages - they are more detailed.
 	}
 
-	return std::string();  // return ok if at least the info was ok.
+	return {};  // return ok if at least the info was ok.
 }
 
 
@@ -374,7 +373,7 @@ A mandatory SMART command failed: exiting. To continue, add one or more '-T perm
 
 	// search at line start, because they are sometimes present in other sentences too.
 	if (app_pcre_match("/^SMART Enabled/mi", output) || app_pcre_match("/^SMART Disabled/mi", output)) {
-		return std::string();  // success
+		return {};  // success
 	}
 
 	if (app_pcre_match("/^A mandatory SMART command failed/mi", output)) {
@@ -409,7 +408,7 @@ A mandatory SMART command failed: exiting. To continue, add one or more '-T perm
 		return error_msg;
 
 	if (app_pcre_match("/Testing Enabled/mi", output) || app_pcre_match("/Testing Disabled/mi", output)) {
-		return std::string();  // success
+		return {};  // success
 	}
 
 	if (app_pcre_match("/^A mandatory SMART command failed/mi", output)) {
@@ -668,7 +667,7 @@ AtaStorageProperty StorageDevice::lookup_property(const std::string& generic_nam
 		if (p.generic_name == generic_name)
 			return p;
 	}
-	return AtaStorageProperty();  // check with .empty()
+	return {};  // check with .empty()
 }
 
 
@@ -781,7 +780,7 @@ std::string StorageDevice::get_device_options() const
 {
 	if (is_virtual_) {
 		debug_out_warn("app", DBG_FUNC_MSG << "Cannot get device options of a virtual device.\n");
-		return std::string();
+		return {};
 	}
 
 	// If we have some special type or option, specify it on the command line (like "-d scsi").
@@ -838,7 +837,7 @@ std::string StorageDevice::execute_device_smartctl(const std::string& command_op
 		return error_msg;
 	}
 
-	return std::string();
+	return {};
 }
 
 
diff --git a/src/applib/storage_settings.h b/src/applib/storage_settings.h
index 8ee1246..1f42630 100644
--- a/src/applib/storage_settings.h
+++ b/src/applib/storage_settings.h
@@ -85,13 +85,13 @@ inline AppDeviceOptionMap app_config_get_device_option_map()
 inline std::string app_get_device_option(const std::string& dev, const std::string& type_arg)
 {
 	if (dev.empty())
-		return std::string();
+		return {};
 
 	auto devmap = app_config_get_device_option_map().value;
 	if (auto iter = devmap.find(std::pair(dev, type_arg)); iter != devmap.end()) {
 		return iter->second;
 	}
-	return std::string();
+	return {};
 }
 
 
diff --git a/src/applib/warning_colors.h b/src/applib/warning_colors.h
index 2acd6f9..f775ff1 100644
--- a/src/applib/warning_colors.h
+++ b/src/applib/warning_colors.h
@@ -85,7 +85,7 @@ inline std::string storage_property_get_warning_reason(const AtaStorageProperty&
 			return Glib::ustring::compose(_("%1ALERT:%2 %3"), start, stop, p.warning_reason);
 	}
 
-	return std::string();
+	return {};
 }
 
 
diff --git a/src/applib/window_instance_manager.h b/src/applib/window_instance_manager.h
index 251c3c7..48ddd25 100644
--- a/src/applib/window_instance_manager.h
+++ b/src/applib/window_instance_manager.h
@@ -73,13 +73,13 @@ class WindowInstanceManager {
 		WindowInstanceManager(const WindowInstanceManager& other) = delete;
 
 		/// Deleted
-		WindowInstanceManager(const WindowInstanceManager&& other) = delete;
+		WindowInstanceManager(WindowInstanceManager&& other) = delete;
 
 		/// Deleted
 		WindowInstanceManager& operator=(const WindowInstanceManager&) = delete;
 
 		/// Deleted
-		WindowInstanceManager& operator=(const WindowInstanceManager&&) = delete;
+		WindowInstanceManager& operator=(WindowInstanceManager&&) = delete;
 
 		/// Default, must be polymorphic for casts to succeed
 		virtual ~WindowInstanceManager() = default;
@@ -125,13 +125,13 @@ class WindowInstanceManager<Child, false> {
 		WindowInstanceManager(const WindowInstanceManager& other) = delete;
 
 		/// Deleted
-		WindowInstanceManager(const WindowInstanceManager&& other) = delete;
+		WindowInstanceManager(WindowInstanceManager&& other) = delete;
 
 		/// Deleted
 		WindowInstanceManager& operator=(const WindowInstanceManager&) = delete;
 
 		/// Deleted
-		WindowInstanceManager& operator=(const WindowInstanceManager&&) = delete;
+		WindowInstanceManager& operator=(WindowInstanceManager&&) = delete;
 
 		/// Default, must be polymorphic for casts to succeed
 		virtual ~WindowInstanceManager() = default;
diff --git a/src/gsc_main_window_iconview.h b/src/gsc_main_window_iconview.h
index 8e5610e..97b9c40 100644
--- a/src/gsc_main_window_iconview.h
+++ b/src/gsc_main_window_iconview.h
@@ -66,7 +66,7 @@ class GscMainWindowIconView : public Gtk::IconView {
 
 
 		/// Constructor, GtkBuilder needs this.
-		GscMainWindowIconView(BaseObjectType* gtkcobj, [[maybe_unused]] const Glib::RefPtr<Gtk::Builder>& ref_ui)
+		[[maybe_unused]] GscMainWindowIconView(BaseObjectType* gtkcobj, [[maybe_unused]] const Glib::RefPtr<Gtk::Builder>& ref_ui)
 				: Gtk::IconView(gtkcobj)
 		{
 			columns.add(col_name);  // we can use the col_name variable by value after this.
@@ -358,16 +358,15 @@ class GscMainWindowIconView : public Gtk::IconView {
 				if (icon) {
 					icon = icon->copy();  // work on a copy
 					if (icon->get_colorspace() == Gdk::COLORSPACE_RGB && icon->get_bits_per_sample() == 8) {
-						int n_channels = icon->get_n_channels();
-						int icon_width = icon->get_width();
-						int icon_height = icon->get_height();
-						int rowstride = icon->get_rowstride();
+						std::ptrdiff_t n_channels = icon->get_n_channels();
+						std::ptrdiff_t icon_width = icon->get_width();
+						std::ptrdiff_t icon_height = icon->get_height();
+						std::ptrdiff_t rowstride = icon->get_rowstride();
 						guint8* pixels = icon->get_pixels();
 
-						guint8* p = nullptr;
-						for (int y = 0; y < icon_height; ++y) {
-							for (int x = 0; x < icon_width; ++x) {
-								p = pixels + y * rowstride + x * n_channels;
+						for (std::ptrdiff_t y = 0; y < icon_height; ++y) {
+							for (std::ptrdiff_t x = 0; x < icon_width; ++x) {
+								guint8* p = pixels + y * rowstride + x * n_channels;
 								auto avg = static_cast<uint8_t>(std::floor((p[0] * 0.30) + (p[1] * 0.59) + (p[2] * 0.11) + 0.001 + 0.5));
 								p[0] = avg;  // R
 								p[1] = 0;  // G
@@ -459,7 +458,7 @@ class GscMainWindowIconView : public Gtk::IconView {
 				if (drive == row.get_value(col_drive_ptr).get())
 					return ref_list_model->get_path(row);
 			}
-			return Gtk::TreePath();  // check with .empty()
+			return {};  // check with .empty()
 		}
 
 
@@ -530,7 +529,7 @@ class GscMainWindowIconView : public Gtk::IconView {
 					Gtk::CellRenderer* cell = nullptr;
 					if (this->get_cursor(cell) && cell) {
 						// gtkmm's set_cursor() is undefined (but declared) in 2.8, so use gtk variant.
-						gtk_icon_view_set_cursor(GTK_ICON_VIEW(this->gobj()), tpath.gobj(), cell->gobj(), false);
+						gtk_icon_view_set_cursor(GTK_ICON_VIEW(this->gobj()), tpath.gobj(), cell->gobj(), FALSE);
 					}
 
 					// select the icon
diff --git a/src/hz/bad_cast_exception.h b/src/hz/bad_cast_exception.h
index 9f7fa74..b8328f0 100644
--- a/src/hz/bad_cast_exception.h
+++ b/src/hz/bad_cast_exception.h
@@ -36,7 +36,7 @@ class bad_cast_except : public std::exception {  // from <exception>
 		/// \param error_msg error message
 		bad_cast_except(const std::type_info& src, const std::type_info& dest,
 				const char* self_name = nullptr, const char* error_msg = nullptr)
-			: src_type(src), dest_type(dest),
+			: src_type_(src), dest_type_(dest),
 			self_name_(self_name ? self_name : "bad_cast_except"),
 			error_msg_(error_msg ? error_msg : "Type cast failed from \"%s\" to \"%s\".")  // still need %s here for correct arg count for printf
 		{ }
@@ -49,24 +49,37 @@ class bad_cast_except : public std::exception {  // from <exception>
 			// an out-of-memory exception, what the heck.
 			std::string who = (self_name_.empty() ? "[unknown]" : self_name_);
 
-			std::string from = (src_type == typeid(void) ? "[unknown]" : hz::type_name_demangle(src_type.name()));
+			std::string from = (src_type_ == typeid(void) ? "[unknown]" : hz::type_name_demangle(src_type_.name()));
 			if (from.empty())
-				from = src_type.name();
+				from = src_type_.name();
 
-			std::string to = (dest_type == typeid(void) ? "[unknown]" : hz::type_name_demangle(dest_type.name()));
+			std::string to = (dest_type_ == typeid(void) ? "[unknown]" : hz::type_name_demangle(dest_type_.name()));
 			if (to.empty())
-				to = dest_type.name();
+				to = dest_type_.name();
 
 			return (msg_ = hz::string_sprintf((who + ": " + error_msg_).c_str(), from.c_str(), to.c_str())).c_str();
 		}
 
 
-		const std::type_info& src_type;  ///< Cast source type info. Can be a reference since type_info objects are guaranteed to live forever.
-		const std::type_info& dest_type;  ///< Cast destination type info
+		/// Get source type
+		const std::type_info& src_type() const
+		{
+			return src_type_;
+		}
+
+
+		/// Get destination type
+		const std::type_info& dest_type() const
+		{
+			return dest_type_;
+		}
 
 
 	private:
 
+		const std::type_info& src_type_;  ///< Cast source type info. Can be a reference since type_info objects are guaranteed to live forever.
+		const std::type_info& dest_type_;  ///< Cast destination type info
+
 		mutable std::string msg_;  ///< This must be a member to avoid its destruction on function call return. use what().
 
 		std::string self_name_;  ///< The exception class name
diff --git a/src/hz/data_file.h b/src/hz/data_file.h
index 8615e8f..192b0ea 100644
--- a/src/hz/data_file.h
+++ b/src/hz/data_file.h
@@ -50,7 +50,7 @@ inline std::vector<fs::path> data_file_get_search_directories(const std::string&
 	if (DataFileStaticHolder::search_directories.count(domain) > 0) {
 		return DataFileStaticHolder::search_directories.at(domain);
 	}
-	return std::vector<fs::path>();
+	return {};
 }
 
 
@@ -68,19 +68,19 @@ inline void data_file_set_search_directories(const std::string& domain, std::vec
 inline fs::path data_file_find(const std::string& domain, const std::string& filename, bool allow_to_be_directory = false)
 {
 	if (filename.empty())
-		return fs::path();
+		return {};
 
 	if (fs::u8path(filename).is_absolute()) {  // shouldn't happen
 		debug_print_error("app", "%s: Data file \"%s\" must be relative.\n",
 				DBG_FUNC, filename.c_str());
-		return fs::path();
+		return {};
 	}
 
 	auto dirs = data_file_get_search_directories(domain);
 	if (dirs.empty()) {  // shouldn't happen
 		debug_print_error("app", "%s: No search directories registered for domain \"%s\".\n",
 				DBG_FUNC, domain.c_str());
-		return fs::path();
+		return {};
 	}
 
 	for (const auto& dir : dirs) {
@@ -91,7 +91,7 @@ inline fs::path data_file_find(const std::string& domain, const std::string& fil
 			if (!allow_to_be_directory && fs::is_directory(file_path, ec)) {
 				debug_print_error("app", "%s: Data file \"[%s:]%s\" file found at \"%s\", but it is a directory.\n",
 						DBG_FUNC, domain.c_str(), file_path.string().c_str(), dir.string().c_str());
-				return fs::path();
+				return {};
 			}
 			debug_print_info("app", "%s: Data file \"[%s:]%s\" found at \"%s\".\n",
 					DBG_FUNC, domain.c_str(), file_path.string().c_str(), dir.string().c_str());
@@ -101,7 +101,7 @@ inline fs::path data_file_find(const std::string& domain, const std::string& fil
 
 	debug_print_error("app", "%s: Data file \"[%s:]%s\" not found.\n",
 			DBG_FUNC, domain.c_str(), filename.c_str());
-	return fs::path();
+	return {};
 }
 
 
@@ -115,12 +115,11 @@ inline std::string data_file_get_contents(const std::string& domain, const std::
 		auto ec = hz::fs_file_get_contents(file, contents, max_size);
 		if (!ec) {
 			return contents;
-		} else {
-			debug_print_error("app", "%s: Data file \"[%s:]%s\" cannot be loaded: %s.\n",
-					DBG_FUNC, domain.c_str(), filename.c_str(), ec.message().c_str());
 		}
+		debug_print_error("app", "%s: Data file \"[%s:]%s\" cannot be loaded: %s.\n",
+				DBG_FUNC, domain.c_str(), filename.c_str(), ec.message().c_str());
 	}
-	return std::string();
+	return {};
 }
 
 
diff --git a/src/hz/env_tools.h b/src/hz/env_tools.h
index 4d9a8bb..f96ef55 100644
--- a/src/hz/env_tools.h
+++ b/src/hz/env_tools.h
@@ -157,7 +157,7 @@ inline bool env_set_value(const std::string& name, const std::string& value, boo
 
 	// glib version may be thread-unsafe on win32, so don't use it there.
 #elif defined ENABLE_GLIB && ENABLE_GLIB
-	return g_setenv(name.c_str(), value.c_str(), overwrite) != 0;  // may be thread-unsafe
+	return g_setenv(name.c_str(), value.c_str(), static_cast<gboolean>(overwrite)) != 0;  // may be thread-unsafe
 
 
 #elif defined HAVE_SETENV && HAVE_SETENV
diff --git a/src/hz/error.h b/src/hz/error.h
index 8d9451c..2e459fd 100644
--- a/src/hz/error.h
+++ b/src/hz/error.h
@@ -66,32 +66,46 @@ class ErrorBase {
 
 
 		/// Constructor
-		ErrorBase(std::string type_, ErrorLevel level_, std::string msg)
-				: type(std::move(type_)), level(level_), message(std::move(msg))
+		ErrorBase(std::string type, ErrorLevel level, std::string message)
+				: type_(std::move(type)), level_(level), message_(std::move(message))
 		{ }
 
 		/// Constructor
-		ErrorBase(std::string type_, ErrorLevel level_)
-				: type(std::move(type_)), level(level_)
+		ErrorBase(std::string type, ErrorLevel level)
+				: type_(std::move(type)), level_(level)
 		{ }
 
+		/// Defaulted
+		ErrorBase(const ErrorBase& other) = default;
+
+		/// Defaulted
+		ErrorBase(ErrorBase&& other) = default;
+
+		/// Defaulted
+		ErrorBase& operator=(const ErrorBase&) = default;
+
+		/// Defaulted
+		ErrorBase& operator=(ErrorBase&&) = default;
+
+
 		/// Virtual destructor
 		virtual ~ErrorBase() = default;
 
+
 		/// Clone this object
 		[[nodiscard]] virtual ErrorBase* clone() = 0;  // needed for copying by base pointers
 
 
 		/// Get std::type_info for the error code type.
-		[[nodiscard]] virtual const std::type_info& get_code_type() const = 0;
+		[[nodiscard]] virtual const std::type_info& get_code_type_info() const = 0;
 
 		
 		/// Get error code of type \c CodeMemberType
 		template<class CodeMemberType>
 		CodeMemberType get_code() const  // this may throw on bad cast!
 		{
-			if (get_code_type() != typeid(CodeMemberType))
-				throw type_mismatch(get_code_type(), typeid(CodeMemberType));
+			if (get_code_type_info() != typeid(CodeMemberType))
+				throw type_mismatch(get_code_type_info(), typeid(CodeMemberType));
 			return static_cast<const Error<CodeMemberType>*>(this)->code;
 		}
 
@@ -99,9 +113,9 @@ class ErrorBase {
 		template<class CodeMemberType>
 		bool get_code(CodeMemberType& put_it_here) const  // this doesn't throw
 		{
-			if (get_code_type() != typeid(CodeMemberType))
+			if (get_code_type_info() != typeid(CodeMemberType))
 				return false;
-			put_it_here = static_cast<const Error<CodeMemberType>*>(this)->code;
+			put_it_here = static_cast<const Error<CodeMemberType>*>(this)->get_code_member();
 			return true;
 		}
 
@@ -109,47 +123,67 @@ class ErrorBase {
 		/// Increase the level (severity) of the error
 		ErrorLevel level_inc()
 		{
-			if (level == ErrorLevel::fatal)
-				return level;
-			return (level = static_cast<ErrorLevel>(static_cast<int>(level) << 1));
+			if (level_ == ErrorLevel::fatal)
+				return level_;
+			return (level_ = static_cast<ErrorLevel>(static_cast<int>(level_) << 1));
 		}
 
 		/// Decrease the level (severity) of the error
 		ErrorLevel level_dec()
 		{
-			if (level == ErrorLevel::none)
-				return level;
-			return (level = static_cast<ErrorLevel>(static_cast<int>(level) >> 1));
+			if (level_ == ErrorLevel::none)
+				return level_;
+			return (level_ = static_cast<ErrorLevel>(static_cast<int>(level_) >> 1));
 		}
 
 		/// Get error level (severity)
 		[[nodiscard]] ErrorLevel get_level() const
 		{
-			return level;
+			return level_;
 		}
 
 
 		/// Get error type
 		[[nodiscard]] std::string get_type() const
 		{
-			return type;
+			return type_;
 		}
 
 		/// Get error message
 		[[nodiscard]] std::string get_message() const
 		{
-			return message;
+			return message_;
 		}
 
 
-		// no set_type, set_message - we don't allow changing those.
-
-
 	protected:
 
-		std::string type;  ///< Error type
-		ErrorLevel level = ErrorLevel::none;  ///< Error severity
-		std::string message;  ///< Error message
+		/// Set error type
+		void set_type(std::string type)
+		{
+			type_ = std::move(type);
+		}
+
+
+		/// Set error level
+		void set_level(ErrorLevel level)
+		{
+			level_ = level;
+		}
+
+
+		/// Set error message
+		void set_message(std::string message)
+		{
+			message_ = std::move(message);
+		}
+
+
+	private:
+
+		std::string type_;  ///< Error type
+		ErrorLevel level_ = ErrorLevel::none;  ///< Error severity
+		std::string message_;  ///< Error message
 
 };
 
@@ -163,25 +197,33 @@ class ErrorCodeHolder : public ErrorBase {
 	protected:
 
 		/// Constructor
-		ErrorCodeHolder(const std::string& type_, ErrorLevel level_, const CodeType& code_,
+		ErrorCodeHolder(const std::string& type, ErrorLevel level, const CodeType& code,
 				const std::string& msg)
-			: ErrorBase(type_, level_, msg), code(code_)
+			: ErrorBase(type, level, msg), code_(code)
 		{ }
 
 		/// Constructor
-		ErrorCodeHolder(const std::string& type_, ErrorLevel level_, const CodeType& code_)
-			: ErrorBase(type_, level_), code(code_)
+		ErrorCodeHolder(const std::string& type, ErrorLevel level, const CodeType& code)
+			: ErrorBase(type, level), code_(code)
 		{ }
 
 	public:
 
 		// Reimplemented from ErrorBase
-		[[nodiscard]] const std::type_info& get_code_type() const override
+		[[nodiscard]] const std::type_info& get_code_type_info() const override
 		{
 			return typeid(CodeType);
 		}
 
-		CodeType code = CodeType();  ///< Error code. We have a class specialization for references too
+		// Reimplemented from ErrorBase
+		[[nodiscard]] const CodeType& get_code_member() const
+		{
+			return code_;
+		}
+
+	private:
+
+		CodeType code_ = CodeType();  ///< Error code. We have a class specialization for references too
 
 };
 
@@ -193,14 +235,14 @@ class ErrorCodeHolder<void> : public ErrorBase {
 	protected:
 
 		/// Constructor
-		ErrorCodeHolder(const std::string& type_, ErrorLevel level_, const std::string& msg)
-			: ErrorBase(type_, level_, msg)
+		ErrorCodeHolder(const std::string& type, ErrorLevel level, const std::string& msg)
+			: ErrorBase(type, level, msg)
 		{ }
 
 	public:
 
 		// Reimplemented from ErrorBase
-		[[nodiscard]] const std::type_info& get_code_type() const override
+		[[nodiscard]] const std::type_info& get_code_type_info() const override
 		{
 			return typeid(void);
 		}
@@ -219,16 +261,16 @@ class Error : public ErrorCodeHolder<CodeType> {
 	public:
 
 		/// Constructor
-		Error(const std::string& type_, ErrorLevel level_, const CodeType& code_,
+		Error(const std::string& type, ErrorLevel level, const CodeType& code,
 				const std::string& msg)
-			: ErrorCodeHolder<CodeType>(type_, level_, code_, msg)
+			: ErrorCodeHolder<CodeType>(type, level, code, msg)
 		{ }
 
 		// Reimplemented from ErrorBase
 		ErrorBase* clone() override
 		{
-			return new Error(ErrorCodeHolder<CodeType>::type, ErrorCodeHolder<CodeType>::level,
-					ErrorCodeHolder<CodeType>::code, ErrorCodeHolder<CodeType>::message);
+			return new Error(ErrorCodeHolder<CodeType>::get_type(), ErrorCodeHolder<CodeType>::get_level(),
+					ErrorCodeHolder<CodeType>::get_code_member(), ErrorCodeHolder<CodeType>::get_message());
 		}
 };
 
@@ -240,15 +282,15 @@ template<>
 class Error<void> : public ErrorCodeHolder<void> {
 	public:
 
-		Error(const std::string& type_, ErrorLevel level_, const std::string& msg)
-			: ErrorCodeHolder<void>(type_, level_, msg)
+		Error(const std::string& type, ErrorLevel level, const std::string& msg)
+			: ErrorCodeHolder<void>(type, level, msg)
 		{ }
 
 		// Reimplemented from ErrorBase
 		ErrorBase* clone() override
 		{
-			return new Error(ErrorCodeHolder<void>::type, ErrorCodeHolder<void>::level,
-					ErrorCodeHolder<void>::message);
+			return new Error(ErrorCodeHolder<void>::get_type(), ErrorCodeHolder<void>::get_level(),
+					ErrorCodeHolder<void>::get_message());
 		}
 };
 
@@ -262,20 +304,20 @@ class Error<int> : public ErrorCodeHolder<int> {
 	public:
 
 		/// Constructor
-		Error(const std::string& type_, ErrorLevel level_, int code_, const std::string& msg)
-			: ErrorCodeHolder<int>(type_, level_, code_, msg)
+		Error(const std::string& type, ErrorLevel level, int code, const std::string& msg)
+			: ErrorCodeHolder<int>(type, level, code, msg)
 		{ }
 
 		/// Constructor
-		Error(const std::string& type_, ErrorLevel level_, int code_)
-			: ErrorCodeHolder<int>(type_, level_, code_)
+		Error(const std::string& type, ErrorLevel level, int code)
+			: ErrorCodeHolder<int>(type, level, code)
 		{
 			if (type == "errno") {
-				message = std::error_code(code_, std::system_category()).message();
+				this->set_message(std::error_code(code, std::system_category()).message());
 
 			} else if (type == "signal") {
 				// hz::signal_string should be translated already
-				message = "Child exited with signal: " + hz::signal_to_string(code_);
+				this->set_message("Child exited with signal: " + hz::signal_to_string(code));
 
 			} else {  // nothing else supported here. use constructor with a message.
 				DBG_ASSERT(0);
@@ -285,8 +327,8 @@ class Error<int> : public ErrorCodeHolder<int> {
 		// Reimplemented from ErrorBase
 		ErrorBase* clone() override
 		{
-			return new Error(ErrorCodeHolder<int>::type, ErrorCodeHolder<int>::level,
-					ErrorCodeHolder<int>::code, ErrorCodeHolder<int>::message);
+			return new Error(ErrorCodeHolder<int>::get_type(), ErrorCodeHolder<int>::get_level(),
+					ErrorCodeHolder<int>::get_code_member(), ErrorCodeHolder<int>::get_message());
 		}
 };
 
diff --git a/src/hz/error_holder.h b/src/hz/error_holder.h
index 974cfeb..6e20e2e 100644
--- a/src/hz/error_holder.h
+++ b/src/hz/error_holder.h
@@ -30,6 +30,21 @@ class ErrorHolder {
 
 		using error_list_t = std::vector<std::shared_ptr<ErrorBase>>;  ///< A list of ErrorBase* pointers
 
+		/// Defaulted
+		ErrorHolder() = default;
+
+		/// Deleted
+		ErrorHolder(const ErrorHolder& other) = delete;
+
+		/// Deleted
+		ErrorHolder(ErrorHolder&& other) = delete;
+
+		/// Deleted
+		ErrorHolder& operator=(const ErrorHolder&) = delete;
+
+		/// Deleted
+		ErrorHolder& operator=(ErrorHolder&&) = delete;
+
 		/// Virtual destructor
 		virtual ~ErrorHolder() = default;
 
@@ -85,7 +100,7 @@ class ErrorHolder {
 		}
 
 
-	protected:
+	private:
 
 		error_list_t errors_;  ///< Error list. The newest errors at the end.
 
diff --git a/src/hz/format_unit.h b/src/hz/format_unit.h
index 1b90b85..410d297 100644
--- a/src/hz/format_unit.h
+++ b/src/hz/format_unit.h
@@ -177,12 +177,13 @@ inline std::string format_time_length(std::chrono::seconds secs)
 					std::vector<std::string>{"{days}", "{hours}"},
 					std::vector<std::string>{std::to_string(days.count()), std::to_string(hours)});
 
-		} else {  // display days only
-			return hz::string_replace_copy(C_("time", "{days} d"),
-					"{days}", std::to_string(days.count()));
 		}
+		// display days only
+		return hz::string_replace_copy(C_("time", "{days} d"),
+			"{days}", std::to_string(days.count()));
+	}
 
-	} else if (secs >= 100min) {
+	if (secs >= 100min) {
 		auto hours = std::chrono::round<std::chrono::hours>(secs);
 		std::chrono::seconds sec_diff = secs - hours;
 
@@ -195,11 +196,12 @@ inline std::string format_time_length(std::chrono::seconds secs)
 					std::vector<std::string>{"{hours}", "{minutes}"},
 					std::vector<std::string>{std::to_string(hours.count()), std::to_string(minutes)});
 
-		} else {  // display hours only
-			return std::to_string(hours.count()) + " " + "h";
 		}
+		// display hours only
+		return std::to_string(hours.count()) + " " + "h";
+	}
 
-	} else if (secs >= 100s) {
+	if (secs >= 100s) {
 		auto minutes = std::chrono::round<std::chrono::minutes>(secs);
 		return hz::string_replace_copy(C_("time", "{minutes} min"),
 				"{minutes}", std::to_string(minutes.count()));
@@ -222,7 +224,7 @@ inline std::string format_time_length(std::chrono::seconds secs)
 inline std::string format_date(const std::string& format, const struct std::tm* ltmp, bool use_classic_locale)
 {
 	if (!ltmp || format.empty())
-		return std::string();
+		return {};
 
 	std::ostringstream ss;
 	if (!use_classic_locale) {
@@ -250,7 +252,7 @@ inline std::string format_date(const std::string& format, std::time_t timet, boo
 #else
 	struct std::tm ltm = {};
 	if (!localtime_r(&timet, &ltm))  // use reentrant localtime_r (posix/bsd and related)
-		return std::string();
+		return {};
 	const struct std::tm* ltmp = &ltm;
 #endif
 
@@ -265,7 +267,7 @@ inline std::string format_date(const std::string& format, bool use_classic_local
 {
 	const std::time_t timet = std::time(nullptr);
 	if (timet == static_cast<std::time_t>(-1))
-		return std::string();
+		return {};
 
 	return format_date(format, timet, use_classic_locale);
 }
diff --git a/src/hz/fs.h b/src/hz/fs.h
index 4240165..a7598da 100644
--- a/src/hz/fs.h
+++ b/src/hz/fs.h
@@ -19,6 +19,7 @@ Copyright:
 #include <cstdio>  // std::FILE, std::fopen() and friends
 #include <stdio.h>  // off_t, fileno(), _fileno(), _wfopen()
 #include <limits>
+#include <array>
 
 #ifdef _WIN32
 	#include <io.h>  // _waccess*()
@@ -161,7 +162,7 @@ inline std::error_code fs_file_get_contents_noalloc(const fs::path& file, unsign
 
 	std::FILE* f = fs_platform_fopen(file, "rb");
 	if (!f) {
-		return std::error_code(errno, std::system_category());
+		return {errno, std::system_category()};
 	}
 
 	std::error_code ec;
@@ -271,19 +272,19 @@ inline std::error_code fs_file_get_contents_unseekable(const hz::fs::path& file,
 {
 	std::FILE* fp = fs_platform_fopen(file, "rb");
 	if (!fp) {
-		return std::error_code(errno, std::system_category());;
+		return {errno, std::system_category()};
 	}
 	put_data_here.clear();
 
-	char line[1024] = {0};
-	while (std::fgets(line, static_cast<int>(sizeof(line)), fp) != nullptr) {
-		if (*line != '\0')
-			put_data_here += line;  // line contains the terminating newline as well
+	std::array<char, 1024> line = {};
+	while (std::fgets(line.data(), static_cast<int>(line.size()), fp) != nullptr) {
+		if (line[0] != '\0')
+			put_data_here += line.data();  // line contains the terminating newline as well
 	}
 
 	std::fclose(fp);
 
-	return std::error_code();
+	return {};
 }
 
 
@@ -299,7 +300,7 @@ inline std::error_code fs_file_put_contents(const fs::path& file, const unsigned
 
 	std::FILE* f = fs_platform_fopen(file, "wb");
 	if (!f) {
-		return std::error_code(errno, std::system_category());
+		return {errno, std::system_category()};
 	}
 
 	// We write in chunks to support large files.
@@ -328,9 +329,9 @@ inline std::error_code fs_file_put_contents(const fs::path& file, const unsigned
 	}
 
 	if (std::fclose(f) != 0)
-		return std::error_code(errno, std::system_category());
+		return {errno, std::system_category()};
 
-	return std::error_code();
+	return {};
 }
 
 
@@ -386,7 +387,7 @@ inline fs::path fs_get_home_dir()
 		return fs::temp_directory_path(ec);
 	}
 
-	return fs::path(dir);  // native encoding
+	return {dir};  // native encoding
 #endif
 }
 
diff --git a/src/hz/launch_url.h b/src/hz/launch_url.h
index 55d11e7..da7d2cc 100644
--- a/src/hz/launch_url.h
+++ b/src/hz/launch_url.h
@@ -51,10 +51,10 @@ inline std::string launch_url([[maybe_unused]] GtkWindow* window, const std::str
 
 	GError* error = nullptr;
 #if GTK_CHECK_VERSION(3, 22, 0)
-	bool status = gtk_show_uri_on_window(window, link.c_str(), GDK_CURRENT_TIME, &error);
+	bool status = static_cast<bool>(gtk_show_uri_on_window(window, link.c_str(), GDK_CURRENT_TIME, &error));
 #else
 	GdkScreen* screen = (window ? gtk_window_get_screen(window) : nullptr);
-	bool status = (bool)gtk_show_uri(screen, link.c_str(), GDK_CURRENT_TIME, &error);
+	bool status = static_cast<bool>(gtk_show_uri(screen, link.c_str(), GDK_CURRENT_TIME, &error));
 #endif
 	std::unique_ptr<GError, decltype(&g_error_free)> uerror(error, &g_error_free);
 
@@ -62,7 +62,7 @@ inline std::string launch_url([[maybe_unused]] GtkWindow* window, const std::str
 		return std::string("Cannot open URL: ")
 				+ ((error && error->message) ? (std::string(": ") + error->message) : ".");
 	}
-	return std::string();
+	return {};
 #endif
 }
 
diff --git a/src/hz/locale_tools.h b/src/hz/locale_tools.h
index ef25659..d250648 100644
--- a/src/hz/locale_tools.h
+++ b/src/hz/locale_tools.h
@@ -191,7 +191,7 @@ std::string locale_cpp_get<std::string>()
 template<> inline
 std::locale locale_cpp_get<std::locale>()
 {
-	return std::locale();
+	return {};
 }
 
 
@@ -219,6 +219,19 @@ class ScopedCLocale {
 			}
 		}
 
+		/// Deleted
+		ScopedCLocale(const ScopedCLocale& other) = delete;
+
+		/// Deleted
+		ScopedCLocale(ScopedCLocale&& other) = delete;
+
+		/// Deleted
+		ScopedCLocale& operator=(const ScopedCLocale&) = delete;
+
+		/// Deleted
+		ScopedCLocale& operator=(ScopedCLocale&&) = delete;
+
+
 		/// Change back the locale
 		~ScopedCLocale()
 		{
@@ -287,12 +300,26 @@ class ScopedCppLocale {
 			}
 		}
 
+		/// Deleted
+		ScopedCppLocale(const ScopedCppLocale& other) = delete;
+
+		/// Deleted
+		ScopedCppLocale(ScopedCppLocale&& other) = delete;
+
+		/// Deleted
+		ScopedCppLocale& operator=(const ScopedCppLocale&) = delete;
+
+		/// Deleted
+		ScopedCppLocale& operator=(ScopedCppLocale&&) = delete;
+
+
 		/// Change the locale back to the old one
 		~ScopedCppLocale()
 		{
 			this->restore();
 		}
 
+
 		/// Get the old locale
 		[[nodiscard]] std::locale old() const
 		{
diff --git a/src/hz/main_tools.h b/src/hz/main_tools.h
index 1c6bdc0..59eb2fb 100644
--- a/src/hz/main_tools.h
+++ b/src/hz/main_tools.h
@@ -34,7 +34,7 @@ int main_exception_wrapper(MainImplFunc main_impl) noexcept
 		return main_impl();
 	}
 	catch(std::exception& e) {
-		// don't use anything other than cerr here, it's the most safe option.
+		// don't use anything other than cerr here, it's the safest option.
 		std::cerr << "main(): Unhandled exception: " << e.what() << std::endl;
 		if (const auto* ex_type = get_current_exception_type()) {
 			std::cerr << "Type of exception: " << type_name_demangle(ex_type->name()) << std::endl;
diff --git a/src/hz/string_algo.h b/src/hz/string_algo.h
index 48bb3e8..f96413f 100644
--- a/src/hz/string_algo.h
+++ b/src/hz/string_algo.h
@@ -51,9 +51,8 @@ void string_split(const std::string& str, char delimiter,
 			if (++num == limit) {
 				append_here.push_back(str.substr(last, std::string::npos));
 				break;
-			} else {
-				append_here.push_back(str.substr(last, (curr == std::string::npos ? curr : (curr - last))));
 			}
+			append_here.push_back(str.substr(last, (curr == std::string::npos ? curr : (curr - last))));
 		}
 
 		if (curr == std::string::npos)
@@ -98,9 +97,8 @@ void string_split(const std::string& str, const std::string& delimiter,
 			if (++num == limit) {
 				append_here.push_back(str.substr(last, std::string::npos));
 				break;
-			} else {
-				append_here.push_back(component);
 			}
+			append_here.push_back(component);
 		}
 
 		if (curr == std::string::npos)
@@ -137,9 +135,8 @@ void string_split_by_chars(const std::string& str, const std::string& delimiter_
 			if (++num == limit) {
 				append_here.push_back(str.substr(last, std::string::npos));
 				break;
-			} else {
-				append_here.push_back(str.substr(last, (curr == std::string::npos ? curr : (curr - last))));
 			}
+			append_here.push_back(str.substr(last, (curr == std::string::npos ? curr : (curr - last))));
 		}
 
 		if (curr == std::string::npos)
@@ -203,10 +200,11 @@ inline bool string_trim(std::string& s, const std::string& trim_chars = " \t\r\n
 		s.erase(index + 1);  // from index+1 to the end
 
 	index = s.find_first_not_of(trim_chars);
-	if (index != std::string::npos)
+	if (index != std::string::npos) {
 		s.erase(0, index);
-	else
+	} else {
 		s.clear();
+	}
 
 	return s_size != s.size();  // true if s was modified
 }
@@ -234,10 +232,11 @@ inline bool string_trim_left(std::string& s, const std::string& trim_chars = " \
 	const auto s_size = s.size();
 
 	std::string::size_type index = s.find_first_not_of(trim_chars);
-	if (index != std::string::npos)
+	if (index != std::string::npos) {
 		s.erase(0, index);
-	else
+	} else {
 		s.clear();
+	}
 
 	return s_size != s.size();  // true if s was modified
 }
@@ -359,7 +358,7 @@ inline bool string_remove_adjacent_duplicates(std::string& s, char c, std::size_
 		return false;
 
 	bool changed = false;
-	std::string::size_type pos1 = 0, pos2;
+	std::string::size_type pos1 = 0, pos2 = 0;
 
 	while ((pos1 = s.find(c, pos1)) != std::string::npos) {
 		pos2 = s.find_first_not_of(c, pos1);
diff --git a/src/hz/string_num.h b/src/hz/string_num.h
index b46600a..598d421 100644
--- a/src/hz/string_num.h
+++ b/src/hz/string_num.h
@@ -202,7 +202,7 @@ namespace internal {
 			return false;
 		const char* str = s.c_str();
 
-		if (boolalpha_enabled) {
+		if (boolalpha_enabled != 0) {
 			// skip spaces. won't do anything in strict mode (we already ruled out spaces there)
 			while (std::isspace(*str, loc)) {
 				++str;
@@ -345,7 +345,7 @@ namespace internal {
 
 	inline std::string number_to_string_impl_bool(bool number, int boolalpha_enabled)
 	{
-		if (boolalpha_enabled)
+		if (boolalpha_enabled != 0)
 			return (number ? "true" : "false");
 		return (number ? "1" : "0");
 	}
@@ -357,7 +357,8 @@ namespace internal {
 		if (number == 0) {
 			if (base == 16) {
 				return "0x" + std::string(sizeof(T) * 2, '0');  // 0 doesn't print as 0x0000, but as 000000. fix that.
-			} else if (base == 8) {  // same here, 0 prints as 0.
+			}
+			if (base == 8) {  // same here, 0 prints as 0.
 				return "00";  // better than simply 0 (at least it's clearly octal).
 			}
 			// base 10 can possibly have some funny formatting, so continue...
@@ -420,7 +421,7 @@ namespace internal {
 			return internal::number_to_string_impl_floating(number, boolalpha_or_base_or_precision, fixed_prec, use_classic_locale);
 		}
 		// unreachable
-		return std::string();
+		return {};
 	}
 
 
diff --git a/src/libdebug/dchannel.h b/src/libdebug/dchannel.h
index 3b751db..4e87444 100644
--- a/src/libdebug/dchannel.h
+++ b/src/libdebug/dchannel.h
@@ -33,6 +33,21 @@ using DebugChannelBasePtr = std::shared_ptr<DebugChannelBase>;
 class DebugChannelBase {
 	public:
 
+		/// Defaulted
+		DebugChannelBase() = default;
+
+		/// Deleted
+		DebugChannelBase(const DebugChannelBase& other) = delete;
+
+		/// Deleted
+		DebugChannelBase(DebugChannelBase&& other) = delete;
+
+		/// Deleted
+		DebugChannelBase& operator=(const DebugChannelBase&) = delete;
+
+		/// Deleted
+		DebugChannelBase& operator=(DebugChannelBase&&) = delete;
+
 		/// Virtual destructor
 		virtual ~DebugChannelBase() = default;
 
diff --git a/src/libdebug/dstream.h b/src/libdebug/dstream.h
index 5936487..b3d4ed2 100644
--- a/src/libdebug/dstream.h
+++ b/src/libdebug/dstream.h
@@ -66,8 +66,17 @@ namespace debug_internal {
 			}
 
 
-			/// Disallow copying
-			DebugStreamBuf(const DebugStreamBuf& from) = delete;
+			/// Deleted
+			DebugStreamBuf(const DebugStreamBuf& other) = delete;
+
+			/// Deleted
+			DebugStreamBuf(DebugStreamBuf&& other) = delete;
+
+			/// Deleted
+			DebugStreamBuf& operator=(const DebugStreamBuf&) = delete;
+
+			/// Deleted
+			DebugStreamBuf& operator=(DebugStreamBuf&&) = delete;
 
 
 			/// Virtual destructor
diff --git a/src/rconfig/autosave.h b/src/rconfig/autosave.h
index 378f770..250802d 100644
--- a/src/rconfig/autosave.h
+++ b/src/rconfig/autosave.h
@@ -51,7 +51,7 @@ extern "C" {
 		bool force = (bool)data;
 
 		if (!force && !impl::autosave_enabled)  // no more autosaves
-			return false;  // remove timeout, disable autosave for real.
+			return FALSE;  // remove timeout, disable autosave for real.
 
 		auto file = impl::autosave_config_file;
 		debug_print_info("rconfig", "Autosaving config to \"%s\".\n", file.u8string().c_str());
@@ -59,14 +59,14 @@ extern "C" {
 		std::error_code ec;
 		if ((hz::fs::exists(file, ec) && !hz::fs::is_regular_file(file, ec)) || !hz::fs_path_is_writable(file, ec)) {
 			debug_out_error("rconfig", "Autosave failed: Cannot write to file: " << ec.message() << "\n");
-			return !force;  // if manual, return failure. else, don't stop the timeout.
+			return static_cast<gboolean>(force);  // if manual, return failure. else, don't stop the timeout.
 		}
 
 		bool status = rconfig::save_to_file(impl::autosave_config_file);
 		if (force)
-			return status;  // return status to caller
+			return static_cast<gboolean>(status);  // return status to caller
 
-		return true;  // continue timeouts
+		return TRUE;  // continue timeouts
 	}
 
 }
@@ -123,7 +123,7 @@ inline void autosave_stop()
 /// Forcibly save the config now.
 inline bool autosave_force_now()
 {
-	return static_cast<bool>(autosave_timeout_callback((void*)true));  // anyone tell me what is the C++ variant of this?
+	return static_cast<bool>(autosave_timeout_callback(reinterpret_cast<void*>(true)));  // anyone tell me what is the C++ variant of this?
 }