diff --git a/src/addressbook/gui/widgets/gal-view-minicard.c b/src/addressbook/gui/widgets/gal-view-minicard.c
index 2e185ee051..a1c61734ba 100644
--- a/src/addressbook/gui/widgets/gal-view-minicard.c
+++ b/src/addressbook/gui/widgets/gal-view-minicard.c
@@ -171,7 +171,7 @@ gal_view_minicard_attach (GalViewMinicard *view,
 	g_return_if_fail (E_IS_MINICARD_VIEW_WIDGET (object));
 
 	gal_view_minicard_detach (view);
-	view->emvw = g_object_ref (object);
+	view->emvw = E_MINICARD_VIEW_WIDGET (g_object_ref (object));
 
 	g_object_set (view->emvw, "column-width", view->column_width, NULL);
 
diff --git a/src/calendar/gui/e-cal-model.c b/src/calendar/gui/e-cal-model.c
index 76857dd9d4..2a622e3ce4 100644
--- a/src/calendar/gui/e-cal-model.c
+++ b/src/calendar/gui/e-cal-model.c
@@ -1383,7 +1383,7 @@ cal_model_create_component_from_values_thread (EAlertSinkThreadJobData *job_data
 	}
 
 	comp_data = g_object_new (E_TYPE_CAL_MODEL_COMPONENT, NULL);
-	comp_data->client = g_object_ref (client);
+	comp_data->client = E_CAL_CLIENT (g_object_ref (client));
 	comp_data->icalcomp = e_cal_model_create_component_with_defaults_sync (ccd->model, comp_data->client, FALSE, cancellable, error);
 
 	if (comp_data->icalcomp) {
diff --git a/src/calendar/gui/e-cal-ops.c b/src/calendar/gui/e-cal-ops.c
index 609b705423..b98f919dd8 100644
--- a/src/calendar/gui/e-cal-ops.c
+++ b/src/calendar/gui/e-cal-ops.c
@@ -2026,7 +2026,7 @@ transfer_components_thread (EAlertSinkThreadJobData *job_data,
 	}
 
 	if (success && ii > 0)
-		tcd->destination_client = g_object_ref (to_client);
+		tcd->destination_client = E_CAL_CLIENT (g_object_ref (to_client));
 
  out:
 	g_clear_object (&from_client);
diff --git a/src/calendar/gui/e-select-names-renderer.c b/src/calendar/gui/e-select-names-renderer.c
index 03bdc44d1c..5e83997a77 100644
--- a/src/calendar/gui/e-select-names-renderer.c
+++ b/src/calendar/gui/e-select-names-renderer.c
@@ -251,7 +251,7 @@ select_names_renderer_start_editing (GtkCellRenderer *cell,
 		editable, "editing_done",
 		G_CALLBACK (e_select_names_renderer_editing_done), sn_cell);
 
-	sn_cell->priv->editable = g_object_ref (editable);
+	sn_cell->priv->editable = E_SELECT_NAMES_EDITABLE (g_object_ref (editable));
 	sn_cell->priv->path = g_strdup (path);
 
 	g_object_unref (client_cache);
diff --git a/src/calendar/gui/e-week-view.c b/src/calendar/gui/e-week-view.c
index 17424e2c19..a966ddeed5 100644
--- a/src/calendar/gui/e-week-view.c
+++ b/src/calendar/gui/e-week-view.c
@@ -3641,7 +3641,7 @@ tooltip_event_cb (GnomeCanvasItem *item,
 			pevent->y = ((GdkEventCrossing *) event)->y_root;
 			pevent->tooltip = NULL;
 
-			data->cal_view = g_object_ref (view);
+			data->cal_view = E_CALENDAR_VIEW (g_object_ref (view));
 			data->day = -1;
 			data->event_num = event_num;
 			data->get_view_event = (ECalendarViewEvent * (*)(ECalendarView *, int, gint)) tooltip_get_view_event;
@@ -4364,7 +4364,7 @@ e_week_view_on_text_item_event (GnomeCanvasItem *item,
 		pevent->y = (gint) event_y_root;
 		pevent->tooltip = NULL;
 
-		data->cal_view = g_object_ref (week_view);
+		data->cal_view = E_CALENDAR_VIEW (g_object_ref (week_view));
 		data->day = -1;
 		data->event_num = nevent;
 		data->get_view_event = (ECalendarViewEvent * (*)(ECalendarView *, int, gint)) tooltip_get_view_event;
diff --git a/src/composer/e-composer-name-header.c b/src/composer/e-composer-name-header.c
index 1bf7dd4370..6599b93d19 100644
--- a/src/composer/e-composer-name-header.c
+++ b/src/composer/e-composer-name-header.c
@@ -219,7 +219,7 @@ composer_name_header_constructed (GObject *object)
 		entry, "query-tooltip",
 		G_CALLBACK (composer_name_header_entry_query_tooltip_cb),
 		NULL);
-	E_COMPOSER_HEADER (object)->input_widget = g_object_ref_sink (entry);
+	E_COMPOSER_HEADER (object)->input_widget = GTK_WIDGET (g_object_ref_sink (entry));
 
 	e_signal_connect_notify_swapped (
 		object, "notify::visible",
diff --git a/src/e-util/e-attachment-bar.c b/src/e-util/e-attachment-bar.c
index 51631aedfc..45978883db 100644
--- a/src/e-util/e-attachment-bar.c
+++ b/src/e-util/e-attachment-bar.c
@@ -161,7 +161,7 @@ attachment_bar_set_store (EAttachmentBar *bar,
 {
 	g_return_if_fail (E_IS_ATTACHMENT_STORE (store));
 
-	bar->priv->model = g_object_ref (store);
+	bar->priv->model = GTK_TREE_MODEL (g_object_ref (store));
 
 	gtk_icon_view_set_model (
 		GTK_ICON_VIEW (bar->priv->icon_view),
diff --git a/src/e-util/e-import-assistant.c b/src/e-util/e-import-assistant.c
index 395b8ad23b..42cff3eb24 100644
--- a/src/e-util/e-import-assistant.c
+++ b/src/e-util/e-import-assistant.c
@@ -889,7 +889,7 @@ prepare_progress_page (GtkAssistant *assistant,
 	}
 
 	pd = g_slice_new0 (ProgressData);
-	pd->assistant = g_object_ref (assistant);
+	pd->assistant = E_IMPORT_ASSISTANT (g_object_ref (assistant));
 	pd->done = done;
 
 	g_idle_add_full (G_PRIORITY_HIGH_IDLE, run_import_progress_page_idle, pd, NULL);
diff --git a/src/e-util/e-photo-cache.c b/src/e-util/e-photo-cache.c
index 21cb0cafff..111564ab7e 100644
--- a/src/e-util/e-photo-cache.c
+++ b/src/e-util/e-photo-cache.c
@@ -312,7 +312,7 @@ async_context_new (EDataCapture *data_capture,
 		(GDestroyNotify) async_subtask_unref,
 		(GDestroyNotify) NULL);
 
-	async_context->data_capture = g_object_ref (data_capture);
+	async_context->data_capture = G_CONVERTER (g_object_ref (data_capture));
 
 	if (G_IS_CANCELLABLE (cancellable)) {
 		gulong handler_id;
diff --git a/src/e-util/e-preview-pane.c b/src/e-util/e-preview-pane.c
index 272c896532..0f5ecec902 100644
--- a/src/e-util/e-preview-pane.c
+++ b/src/e-util/e-preview-pane.c
@@ -93,7 +93,7 @@ preview_pane_alert_bar_visible_notify_cb (GtkWidget *alert_bar,
 
 static void
 preview_pane_set_web_view (EPreviewPane *preview_pane,
-                           EWebView *web_view)
+			   GtkWidget *web_view)
 {
 	gulong handler_id;
 
diff --git a/src/e-util/test-html-editor-units-utils.c b/src/e-util/test-html-editor-units-utils.c
index 929763bcbf..a286b20db9 100644
--- a/src/e-util/test-html-editor-units-utils.c
+++ b/src/e-util/test-html-editor-units-utils.c
@@ -341,7 +341,7 @@ test_utils_html_editor_created_cb (GObject *source_object,
 			WebKitWebContext *web_context;
 
 			web_context = webkit_web_view_get_context (WEBKIT_WEB_VIEW (cnt_editor));
-			global_web_context = g_object_ref (web_context);
+			global_web_context = G_OBJECT (g_object_ref (web_context));
 		}
 	}
 
diff --git a/src/em-format/e-mail-part-headers.c b/src/em-format/e-mail-part-headers.c
index a08730bed1..5736dd57d3 100644
--- a/src/em-format/e-mail-part-headers.c
+++ b/src/em-format/e-mail-part-headers.c
@@ -124,7 +124,7 @@ mail_part_headers_build_print_model (EMailPartHeaders *part)
 	g_mutex_lock (&part->priv->property_lock);
 
 	g_clear_object (&part->priv->print_model);
-	part->priv->print_model = g_object_ref (list_store);
+	part->priv->print_model = GTK_TREE_MODEL (g_object_ref (list_store));
 
 	g_mutex_unlock (&part->priv->property_lock);
 
diff --git a/src/libemail-engine/e-mail-folder-utils.c b/src/libemail-engine/e-mail-folder-utils.c
index 5f8922824d..99c08284b9 100644
--- a/src/libemail-engine/e-mail-folder-utils.c
+++ b/src/libemail-engine/e-mail-folder-utils.c
@@ -1948,7 +1948,7 @@ e_mail_folder_uri_parse (CamelSession *session,
 
 	if (CAMEL_IS_STORE (service) && folder_name != NULL) {
 		if (out_store != NULL)
-			*out_store = g_object_ref (service);
+			*out_store = CAMEL_STORE (g_object_ref (service));
 
 		if (out_folder_name != NULL) {
 			*out_folder_name = folder_name;
diff --git a/src/libemail-engine/mail-ops.c b/src/libemail-engine/mail-ops.c
index 3ae85d55cd..24280bb811 100644
--- a/src/libemail-engine/mail-ops.c
+++ b/src/libemail-engine/mail-ops.c
@@ -501,7 +501,7 @@ mail_fetch_mail (CamelStore *store,
 
 	m = mail_msg_new (&fetch_mail_info);
 	fm = (struct _filter_mail_msg *) m;
-	fm->session = g_object_ref (session);
+	fm->session = E_MAIL_SESSION (g_object_ref (session));
 	m->store = g_object_ref (store);
 	fm->cache = NULL;
 	if (cancellable)
diff --git a/src/libemail-engine/mail-vfolder.c b/src/libemail-engine/mail-vfolder.c
index 0f866e224d..c1e8e027a3 100644
--- a/src/libemail-engine/mail-vfolder.c
+++ b/src/libemail-engine/mail-vfolder.c
@@ -233,7 +233,7 @@ vfolder_setup (CamelSession *session,
 	gint id;
 
 	m = mail_msg_new (&vfolder_setup_info);
-	m->session = g_object_ref (session);
+	m->session = E_MAIL_SESSION (g_object_ref (session));
 	m->folder = g_object_ref (folder);
 	/* Make sure the query is enclosed in "(match-all ...)", to traverse the folders' content */
 	m->query = (!query || g_str_has_prefix (query, "(match-all ") || strstr (query, "(match-threads ")) ? g_strdup (query) : g_strconcat ("(match-all ", query, ")", NULL);
diff --git a/src/mail/e-mail-config-assistant.c b/src/mail/e-mail-config-assistant.c
index e5d255675d..857dcc9ffb 100644
--- a/src/mail/e-mail-config-assistant.c
+++ b/src/mail/e-mail-config-assistant.c
@@ -785,7 +785,7 @@ mail_config_assistant_constructed (GObject *object)
 
 	page = e_mail_config_receiving_page_new (registry);
 	e_mail_config_assistant_add_page (assistant, page);
-	assistant->priv->receiving_page = g_object_ref (page);
+	assistant->priv->receiving_page = E_MAIL_CONFIG_SERVICE_PAGE (g_object_ref (page));
 
 	e_binding_bind_object_text_property (
 		mail_identity_extension, "address",
@@ -868,7 +868,7 @@ mail_config_assistant_constructed (GObject *object)
 
 	page = e_mail_config_sending_page_new (registry);
 	e_mail_config_assistant_add_page (assistant, page);
-	assistant->priv->sending_page = g_object_ref (page);
+	assistant->priv->sending_page = E_MAIL_CONFIG_SERVICE_PAGE (g_object_ref (page));
 
 	e_binding_bind_object_text_property (
 		mail_identity_extension, "address",
@@ -923,7 +923,7 @@ mail_config_assistant_constructed (GObject *object)
 
 	page = e_mail_config_summary_page_new ();
 	e_mail_config_assistant_add_page (assistant, page);
-	assistant->priv->summary_page = g_object_ref (page);
+	assistant->priv->summary_page = E_MAIL_CONFIG_SUMMARY_PAGE (g_object_ref (page));
 
 	e_binding_bind_property (
 		assistant, "account-backend",
diff --git a/src/mail/e-mail-config-composing-page.c b/src/mail/e-mail-config-composing-page.c
index b50b95fd2f..644a67d0f3 100644
--- a/src/mail/e-mail-config-composing-page.c
+++ b/src/mail/e-mail-config-composing-page.c
@@ -331,7 +331,7 @@ mail_config_composing_page_setup_three_state_value (ESourceMailComposition *comp
 	g_return_if_fail (GTK_IS_TOGGLE_BUTTON (check_button));
 
 	tsd = g_slice_new0 (ThreeStateData);
-	tsd->composition_ext = g_object_ref (composition_ext);
+	tsd->composition_ext = G_OBJECT (g_object_ref (composition_ext));
 	tsd->property_name = g_strdup (property_name);
 
 	g_object_get (tsd->composition_ext, tsd->property_name, &value, NULL);
diff --git a/src/mail/e-mail-display.c b/src/mail/e-mail-display.c
index 57821f9cfa..c7cdd8424c 100644
--- a/src/mail/e-mail-display.c
+++ b/src/mail/e-mail-display.c
@@ -1636,7 +1636,7 @@ mail_display_constructed (GObject *object)
 	e_web_view_register_content_request_for_scheme (web_view, "cid", content_request);
 	g_object_unref (content_request);
 
-	display->priv->attachment_view = g_object_ref_sink (e_attachment_bar_new (display->priv->attachment_store));
+	display->priv->attachment_view = E_ATTACHMENT_VIEW (g_object_ref_sink (e_attachment_bar_new (display->priv->attachment_store)));
 
 	ui_manager = e_attachment_view_get_ui_manager (display->priv->attachment_view);
 	if (ui_manager) {
diff --git a/src/mail/e-mail-reader.c b/src/mail/e-mail-reader.c
index 7733c238d2..ae585b00e7 100644
--- a/src/mail/e-mail-reader.c
+++ b/src/mail/e-mail-reader.c
@@ -2204,7 +2204,7 @@ action_mail_show_source_cb (GtkAction *action,
 	g_free (string);
 
 	closure = g_slice_new0 (EMailReaderClosure);
-	closure->reader = g_object_ref (browser);
+	closure->reader = E_MAIL_READER (g_object_ref (browser));
 	closure->activity = g_object_ref (activity);
 	closure->message_uid = g_strdup (message_uid);
 
diff --git a/src/mail/e-mail-ui-session.c b/src/mail/e-mail-ui-session.c
index 04341d6c89..a00b04da46 100644
--- a/src/mail/e-mail-ui-session.c
+++ b/src/mail/e-mail-ui-session.c
@@ -544,7 +544,7 @@ mail_ui_session_add_service (CamelSession *session,
 		SourceContext *context;
 
 		context = g_slice_new0 (SourceContext);
-		context->session = g_object_ref (session);
+		context->session = E_MAIL_UI_SESSION (g_object_ref (session));
 		context->service = g_object_ref (service);
 
 		/* Prioritize ahead of GTK+ redraws. */
diff --git a/src/mail/em-event.c b/src/mail/em-event.c
index 94c9ea1e2c..c4733365d1 100644
--- a/src/mail/em-event.c
+++ b/src/mail/em-event.c
@@ -197,7 +197,7 @@ em_event_target_new_message (EMEvent *eme,
 		g_object_ref (message);
 	t->target.mask = ~flags;
 	if (composer)
-		t->composer = g_object_ref (G_OBJECT (composer));
+		t->composer = g_object_ref (composer);
 
 	return t;
 }
diff --git a/src/mail/em-folder-tree.c b/src/mail/em-folder-tree.c
index 09c0299bbf..620bfeb81d 100644
--- a/src/mail/em-folder-tree.c
+++ b/src/mail/em-folder-tree.c
@@ -3813,7 +3813,7 @@ em_folder_tree_restore_state (EMFolderTree *folder_tree,
 			service = camel_session_ref_service (
 				CAMEL_SESSION (session), uid);
 			if (CAMEL_IS_STORE (service)) {
-				store = g_object_ref (service);
+				store = CAMEL_STORE (g_object_ref (service));
 				success = TRUE;
 			}
 			if (service != NULL)
diff --git a/src/mail/em-subscription-editor.c b/src/mail/em-subscription-editor.c
index fe0ccc148b..77f881a73d 100644
--- a/src/mail/em-subscription-editor.c
+++ b/src/mail/em-subscription-editor.c
@@ -1433,7 +1433,7 @@ subscription_editor_add_store (EMSubscriptionEditor *editor,
 
 	data = g_slice_new0 (StoreData);
 	data->store = g_object_ref (store);
-	data->tree_view = g_object_ref (widget);
+	data->tree_view = GTK_TREE_VIEW (g_object_ref (widget));
 	data->list_store = GTK_TREE_MODEL (list_store);
 	data->tree_store = GTK_TREE_MODEL (tree_store);
 	data->needs_refresh = TRUE;
@@ -1598,7 +1598,7 @@ subscription_editor_constructed (GObject *object)
 			e_source_get_uid (source));
 
 		if (CAMEL_IS_SUBSCRIBABLE (service))
-			editor->priv->initial_store = g_object_ref (service);
+			editor->priv->initial_store = CAMEL_STORE (g_object_ref (service));
 
 		if (service != NULL)
 			g_object_unref (service);
diff --git a/src/mail/mail-send-recv.c b/src/mail/mail-send-recv.c
index 261c187762..cb13fac3cf 100644
--- a/src/mail/mail-send-recv.c
+++ b/src/mail/mail-send-recv.c
@@ -827,7 +827,7 @@ build_dialog (GtkWindow *parent,
 
 			info = g_malloc0 (sizeof (*info));
 			info->type = type;
-			info->session = g_object_ref (session);
+			info->session = CAMEL_SESSION (g_object_ref (session));
 			info->service = g_object_ref (service);
 			info->cancellable = camel_operation_new ();
 			info->state = allow_send ? SEND_ACTIVE : SEND_COMPLETE;
@@ -915,7 +915,7 @@ build_dialog (GtkWindow *parent,
 		if (info == NULL) {
 			info = g_malloc0 (sizeof (*info));
 			info->type = SEND_SEND;
-			info->session = g_object_ref (session);
+			info->session = CAMEL_SESSION (g_object_ref (session));
 			info->service = g_object_ref (transport);
 			info->cancellable = camel_operation_new ();
 			info->state = SEND_ACTIVE;
@@ -1600,7 +1600,7 @@ receive_update_got_folderinfo (GObject *source_object,
 		struct _refresh_folders_msg *m;
 
 		m = mail_msg_new (&refresh_folders_info);
-		m->store = g_object_ref (send_info->service);
+		m->store = CAMEL_STORE (g_object_ref (send_info->service));
 		m->folders = folders;
 		m->info = send_info;
 		m->finfo = info;  /* takes ownership */
@@ -1980,7 +1980,7 @@ do_mail_send (EMailSession *session,
 	info = g_malloc0 (sizeof (*info));
 	info->type = SEND_SEND;
 	info->progress_bar = NULL;
-	info->session = g_object_ref (session);
+	info->session = CAMEL_SESSION (g_object_ref (session));
 	info->service = g_object_ref (service);
 	info->cancellable = NULL;
 	info->cancel_button = NULL;
diff --git a/src/modules/addressbook/e-book-shell-view-private.c b/src/modules/addressbook/e-book-shell-view-private.c
index 8cd6842ddd..0751e55baa 100644
--- a/src/modules/addressbook/e-book-shell-view-private.c
+++ b/src/modules/addressbook/e-book-shell-view-private.c
@@ -592,9 +592,9 @@ e_book_shell_view_private_constructed (EBookShellView *book_shell_view)
 	e_shell_window_add_action_group_full (shell_window, "contacts-filter", "addressbook");
 
 	/* Cache these to avoid lots of awkward casting. */
-	priv->book_shell_backend = g_object_ref (shell_backend);
-	priv->book_shell_content = g_object_ref (shell_content);
-	priv->book_shell_sidebar = g_object_ref (shell_sidebar);
+	priv->book_shell_backend = E_BOOK_SHELL_BACKEND (g_object_ref (shell_backend));
+	priv->book_shell_content = E_BOOK_SHELL_CONTENT (g_object_ref (shell_content));
+	priv->book_shell_sidebar = E_BOOK_SHELL_SIDEBAR (g_object_ref (shell_sidebar));
 
 	/* Keep our own reference to this so we can
 	 * disconnect our signal handler in dispose(). */
diff --git a/src/modules/calendar/e-cal-base-shell-sidebar.c b/src/modules/calendar/e-cal-base-shell-sidebar.c
index 44e8134384..5644d7aa39 100644
--- a/src/modules/calendar/e-cal-base-shell-sidebar.c
+++ b/src/modules/calendar/e-cal-base-shell-sidebar.c
@@ -589,7 +589,7 @@ e_cal_base_shell_sidebar_selector_data_dropped (ESourceSelector *selector,
 	titd->destination = g_object_ref (destination);
 	titd->do_copy = do_copy;
 	titd->icomp = icomp;
-	titd->selector = g_object_ref (selector);
+	titd->selector = E_CLIENT_SELECTOR (g_object_ref (selector));
 
 	icomp = NULL;
 
diff --git a/src/modules/calendar/e-cal-shell-view-private.c b/src/modules/calendar/e-cal-shell-view-private.c
index b3ed7c7fd1..f0cc8b705e 100644
--- a/src/modules/calendar/e-cal-shell-view-private.c
+++ b/src/modules/calendar/e-cal-shell-view-private.c
@@ -388,9 +388,9 @@ e_cal_shell_view_private_constructed (ECalShellView *cal_shell_view)
 	e_shell_window_add_action_group_full (shell_window, "calendar-filter", "calendar");
 
 	/* Cache these to avoid lots of awkward casting. */
-	priv->cal_shell_backend = g_object_ref (shell_backend);
-	priv->cal_shell_content = g_object_ref (shell_content);
-	priv->cal_shell_sidebar = g_object_ref (shell_sidebar);
+	priv->cal_shell_backend = E_CAL_SHELL_BACKEND (g_object_ref (shell_backend));
+	priv->cal_shell_content = E_CAL_SHELL_CONTENT (g_object_ref (shell_content));
+	priv->cal_shell_sidebar = E_CAL_BASE_SHELL_SIDEBAR (g_object_ref (shell_sidebar));
 
 	calendar = e_cal_base_shell_sidebar_get_date_navigator (priv->cal_shell_sidebar);
 
diff --git a/src/modules/calendar/e-memo-shell-view-actions.c b/src/modules/calendar/e-memo-shell-view-actions.c
index 0a4382d61f..3a9bd899a3 100644
--- a/src/modules/calendar/e-memo-shell-view-actions.c
+++ b/src/modules/calendar/e-memo-shell-view-actions.c
@@ -365,7 +365,7 @@ action_memo_new_cb (GtkAction *action,
 		ECalModelComponent *comp_data;
 
 		comp_data = list->data;
-		client = g_object_ref (comp_data->client);
+		client = E_CLIENT (g_object_ref (comp_data->client));
 		g_slist_free (list);
 	}
 
diff --git a/src/modules/calendar/e-memo-shell-view-private.c b/src/modules/calendar/e-memo-shell-view-private.c
index e6bff42d85..f6ba77c598 100644
--- a/src/modules/calendar/e-memo-shell-view-private.c
+++ b/src/modules/calendar/e-memo-shell-view-private.c
@@ -117,9 +117,9 @@ e_memo_shell_view_private_constructed (EMemoShellView *memo_shell_view)
 	e_shell_window_add_action_group_full (shell_window, "memos-filter", "memos");
 
 	/* Cache these to avoid lots of awkward casting. */
-	priv->memo_shell_backend = g_object_ref (shell_backend);
-	priv->memo_shell_content = g_object_ref (shell_content);
-	priv->memo_shell_sidebar = g_object_ref (shell_sidebar);
+	priv->memo_shell_backend = E_MEMO_SHELL_BACKEND (g_object_ref (shell_backend));
+	priv->memo_shell_content = E_MEMO_SHELL_CONTENT (g_object_ref (shell_content));
+	priv->memo_shell_sidebar = E_CAL_BASE_SHELL_SIDEBAR (g_object_ref (shell_sidebar));
 
 	/* Keep our own reference to this so we can
 	 * disconnect our signal handlers in dispose(). */
diff --git a/src/modules/calendar/e-task-shell-view-actions.c b/src/modules/calendar/e-task-shell-view-actions.c
index 52a5f7e0f5..d90cfbe888 100644
--- a/src/modules/calendar/e-task-shell-view-actions.c
+++ b/src/modules/calendar/e-task-shell-view-actions.c
@@ -435,7 +435,7 @@ action_task_new_cb (GtkAction *action,
 		ECalModelComponent *comp_data;
 
 		comp_data = list->data;
-		client = g_object_ref (comp_data->client);
+		client = E_CLIENT (g_object_ref (comp_data->client));
 		g_slist_free (list);
 	}
 
diff --git a/src/modules/calendar/e-task-shell-view-private.c b/src/modules/calendar/e-task-shell-view-private.c
index e4901911a7..9420905eb2 100644
--- a/src/modules/calendar/e-task-shell-view-private.c
+++ b/src/modules/calendar/e-task-shell-view-private.c
@@ -232,9 +232,9 @@ e_task_shell_view_private_constructed (ETaskShellView *task_shell_view)
 	e_shell_window_add_action_group_full (shell_window, "tasks-filter", "tasks");
 
 	/* Cache these to avoid lots of awkward casting. */
-	priv->task_shell_backend = g_object_ref (shell_backend);
-	priv->task_shell_content = g_object_ref (shell_content);
-	priv->task_shell_sidebar = g_object_ref (shell_sidebar);
+	priv->task_shell_backend = E_TASK_SHELL_BACKEND (g_object_ref (shell_backend));
+	priv->task_shell_content = E_TASK_SHELL_CONTENT (g_object_ref (shell_content));
+	priv->task_shell_sidebar = E_CAL_BASE_SHELL_SIDEBAR (g_object_ref (shell_sidebar));
 
 	priv->settings = e_util_ref_settings ("org.gnome.evolution.calendar");
 
diff --git a/src/modules/contact-photos/e-contact-photo-source.c b/src/modules/contact-photos/e-contact-photo-source.c
index 95c09113bb..ca5f8a650c 100644
--- a/src/modules/contact-photos/e-contact-photo-source.c
+++ b/src/modules/contact-photos/e-contact-photo-source.c
@@ -179,7 +179,7 @@ contact_photo_source_get_client_cb (GObject *source_object,
 		((client == NULL) && (error != NULL)));
 
 	if (client != NULL) {
-		async_context->client = g_object_ref (client);
+		async_context->client = E_BOOK_CLIENT (g_object_ref (client));
 
 		/* The rest of the operation we can run from a
 		 * worker thread to keep the logic flow simple. */
diff --git a/src/modules/itip-formatter/itip-view.c b/src/modules/itip-formatter/itip-view.c
index c7b44fa868..918099aed9 100644
--- a/src/modules/itip-formatter/itip-view.c
+++ b/src/modules/itip-formatter/itip-view.c
@@ -3616,7 +3616,7 @@ itip_view_cal_opened_cb (GObject *source_object,
 		itip_view_set_mode (view, ITIP_VIEW_MODE_PUBLISH);
 	}
 
-	view->priv->current_client = g_object_ref (client);
+	view->priv->current_client = E_CAL_CLIENT (g_object_ref (client));
 
 	set_buttons_sensitive (view);
 
diff --git a/src/modules/mail/e-mail-attachment-handler.c b/src/modules/mail/e-mail-attachment-handler.c
index e3be4f620f..69a050ce54 100644
--- a/src/modules/mail/e-mail-attachment-handler.c
+++ b/src/modules/mail/e-mail-attachment-handler.c
@@ -157,7 +157,7 @@ mail_attachment_handler_get_selected_message (EAttachmentHandler *handler)
 
 exit:
 	if (message == NULL)
-		message = g_object_ref (outer_wrapper);
+		message = CAMEL_MIME_MESSAGE (g_object_ref (outer_wrapper));
 
 	g_clear_object (&mime_part);
 
@@ -758,7 +758,7 @@ mail_attachment_handler_constructed (GObject *object)
 
 	shell = e_shell_get_default ();
 	shell_backend = e_shell_get_backend_by_name (shell, "mail");
-	priv->backend = g_object_ref (shell_backend);
+	priv->backend = E_MAIL_BACKEND (g_object_ref (shell_backend));
 
 	view = e_attachment_handler_get_view (handler);
 
diff --git a/src/modules/mail/e-mail-shell-content.c b/src/modules/mail/e-mail-shell-content.c
index 0133bae52a..e862ea70c9 100644
--- a/src/modules/mail/e-mail-shell-content.c
+++ b/src/modules/mail/e-mail-shell-content.c
@@ -287,7 +287,7 @@ mail_shell_content_constructed (GObject *object)
 	widget = e_mail_paned_view_new (shell_view);
 	gtk_box_pack_start (vbox, widget, TRUE, TRUE, 0);
 
-	priv->mail_view = g_object_ref (widget);
+	priv->mail_view = E_MAIL_VIEW (g_object_ref (widget));
 	gtk_widget_show (widget);
 
 	g_signal_connect (
diff --git a/src/modules/mail/e-mail-shell-view-private.c b/src/modules/mail/e-mail-shell-view-private.c
index 85d4f6bdfc..077c74fe9f 100644
--- a/src/modules/mail/e-mail-shell-view-private.c
+++ b/src/modules/mail/e-mail-shell-view-private.c
@@ -562,9 +562,9 @@ e_mail_shell_view_private_constructed (EMailShellView *mail_shell_view)
 	e_shell_window_add_action_group_full (shell_window, "search-folders", "mail");
 
 	/* Cache these to avoid lots of awkward casting. */
-	priv->mail_shell_backend = g_object_ref (shell_backend);
-	priv->mail_shell_content = g_object_ref (shell_content);
-	priv->mail_shell_sidebar = g_object_ref (shell_sidebar);
+	priv->mail_shell_backend = E_MAIL_SHELL_BACKEND (g_object_ref (shell_backend));
+	priv->mail_shell_content = E_MAIL_SHELL_CONTENT (g_object_ref (shell_content));
+	priv->mail_shell_sidebar = E_MAIL_SHELL_SIDEBAR (g_object_ref (shell_sidebar));
 
 	mail_shell_sidebar = E_MAIL_SHELL_SIDEBAR (shell_sidebar);
 	folder_tree = e_mail_shell_sidebar_get_folder_tree (mail_shell_sidebar);
@@ -1180,7 +1180,7 @@ update_menu_item_sensitivity_cb (gpointer user_data)
 static void
 service_online_state_changed_cb (GObject *service,
 				 GParamSpec *param,
-				 GObject *menu_item)
+				 GtkWidget *menu_item)
 {
 	EMenuItemSensitivityData *data;
 
@@ -1339,7 +1339,7 @@ send_receive_data_new (EMailShellView *mail_shell_view,
 
 	data = g_slice_new0 (SendReceiveData);
 	data->menu = GTK_MENU_SHELL (menu);  /* do not reference */
-	data->session = g_object_ref (session);
+	data->session = CAMEL_SESSION (g_object_ref (session));
 	data->account_store = g_object_ref (account_store);
 
 	data->menu_items = g_hash_table_new_full (
diff --git a/src/modules/mail/em-composer-prefs.c b/src/modules/mail/em-composer-prefs.c
index b0742a9e18..721c07e6e2 100644
--- a/src/modules/mail/em-composer-prefs.c
+++ b/src/modules/mail/em-composer-prefs.c
@@ -852,7 +852,7 @@ send_account_override_setup (GtkBuilder *builder,
 	widget = e_mail_identity_combo_box_new (registry);
 	e_mail_identity_combo_box_set_allow_aliases (E_MAIL_IDENTITY_COMBO_BOX (widget), TRUE);
 
-	identity_combo_box = g_object_ref_sink (widget);
+	identity_combo_box = E_MAIL_IDENTITY_COMBO_BOX (g_object_ref_sink (widget));
 
 	widget = e_builder_get_widget (builder, "sao-account-treeview");
 	g_return_if_fail (GTK_IS_TREE_VIEW (widget));
diff --git a/src/modules/prefer-plain/e-mail-parser-prefer-plain.c b/src/modules/prefer-plain/e-mail-parser-prefer-plain.c
index 823b4240a1..ed2d44f6ed 100644
--- a/src/modules/prefer-plain/e-mail-parser-prefer-plain.c
+++ b/src/modules/prefer-plain/e-mail-parser-prefer-plain.c
@@ -277,7 +277,7 @@ mail_parser_prefer_plain_convert_text (gpointer user_data)
 
 	g_return_val_if_fail (async_context != NULL, FALSE);
 
-	async_context->web_view = g_object_ref_sink (e_web_view_new ());
+	async_context->web_view = WEBKIT_WEB_VIEW (g_object_ref_sink (e_web_view_new ()));
 
 	e_web_view_load_uri (E_WEB_VIEW (async_context->web_view), "evo://disable-remote-content");
 
diff --git a/src/modules/startup-wizard/e-startup-assistant.c b/src/modules/startup-wizard/e-startup-assistant.c
index 33511ba22e..b5d23e035a 100644
--- a/src/modules/startup-wizard/e-startup-assistant.c
+++ b/src/modules/startup-wizard/e-startup-assistant.c
@@ -141,7 +141,7 @@ startup_assistant_constructed (GObject *object)
 	} else {
 		e_mail_config_assistant_add_page (
 			E_MAIL_CONFIG_ASSISTANT (assistant), page);
-		assistant->priv->import_page = g_object_ref (page);
+		assistant->priv->import_page = E_MAIL_CONFIG_IMPORT_PAGE (g_object_ref (page));
 
 		/* Obviously we only need an import progress page if
 		 * there's a chance we may be importing something. */
diff --git a/src/plugins/mail-to-task/mail-to-task.c b/src/plugins/mail-to-task/mail-to-task.c
index ea223738f6..fdb01ce7d8 100644
--- a/src/plugins/mail-to-task/mail-to-task.c
+++ b/src/plugins/mail-to-task/mail-to-task.c
@@ -1001,7 +1001,7 @@ do_mail_to_event (AsyncData *data)
 			i_cal_component_take_property (icomp, prop);
 
 			mc = g_slice_new0 (struct _manage_comp);
-			mc->client = g_object_ref (client);
+			mc->client = E_CAL_CLIENT (g_object_ref (client));
 			mc->comp = g_object_ref (comp);
 			g_mutex_init (&mc->mutex);
 			g_cond_init (&mc->cond);