(inhibit-read-only t))
     (pop-to-buffer-same-window buffer))
   ;; Don't track undo information for this buffer
-  (set 'buffer-undo-list t)
+  (setq buffer-undo-list t)
   (notmuch-tree-worker query query-context target open-target unthreaded)
   (setq notmuch-tree-parent-buffer parent-buffer)
   (setq truncate-lines t))
 
                    (throw 'return nil))
                  (when (and atbob
                             (not (string= notmuch-search-target-thread "found")))
-                   (set 'never-found-target-thread t)))))
+                   (setq never-found-target-thread t)))))
            (when (and never-found-target-thread
                       notmuch-search-target-line)
              (goto-char (point-min))
       (pop-to-buffer-same-window buffer))
     (notmuch-search-mode)
     ;; Don't track undo information for this buffer
-    (set 'buffer-undo-list t)
-    (set 'notmuch-search-query-string query)
-    (set 'notmuch-search-oldest-first oldest-first)
-    (set 'notmuch-search-target-thread target-thread)
-    (set 'notmuch-search-target-line target-line)
+    (setq buffer-undo-list t)
+    (setq notmuch-search-query-string query)
+    (setq notmuch-search-oldest-first oldest-first)
+    (setq notmuch-search-target-thread target-thread)
+    (setq notmuch-search-target-line target-line)
     (notmuch-tag-clear-cache)
     (let ((proc (get-buffer-process (current-buffer)))
          (inhibit-read-only t))
 This command toggles the sort order for the current search. The
 default sort order is defined by `notmuch-search-oldest-first'."
   (interactive)
-  (set 'notmuch-search-oldest-first (not notmuch-search-oldest-first))
+  (setq notmuch-search-oldest-first (not notmuch-search-oldest-first))
   (notmuch-search-refresh-view))
 
 (defun notmuch-group-disjunctive-query-string (query-string)