--- a/lisp/window.el
+++ b/lisp/window.el
@@ -6887,10 +6887,11 @@ WARNING: This is NOT the way to work on another buffer temporarily
 within a Lisp program!  Use `set-buffer' instead.  That avoids
 messing with the window-buffer correspondences.

-If the selected window cannot display the specified
-buffer (e.g. if it is a minibuffer window or strongly dedicated
-to another buffer), call `pop-to-buffer' to select the buffer in
-another window.
+If the selected window cannot display the specified buffer
+because it is a minibuffer window or strongly dedicated to
+another buffer, call `pop-to-buffer' to select the buffer in
+another window.  In interactive use offer to undedicate the
+selected window before.

 If called interactively, read the buffer name using the
 minibuffer.  The variable `confirm-nonexistent-file-or-buffer'
@@ -6916,7 +6917,15 @@ window.

 Return the buffer switched to."
   (interactive
-   (list (read-buffer-to-switch "Switch to buffer: ") nil 'force-same-window))
+   (let ((force-same-window
+          (and (not (window-minibuffer-p))
+               (or (not (eq (window-dedicated-p) t))
+                   (and (y-or-n-p
+                         (format "Window is dedicated to %s; undedicate it"
+                                 (window-buffer)))
+                        (or (set-window-dedicated-p nil nil) t)))
+               'force-same-window)))
+     (list (read-buffer-to-switch "Switch to buffer: ") nil force-same-window)))
   (let ((buffer (window-normalize-buffer-to-switch-to buffer-or-name)))
     (cond
      ;; Don't call set-window-buffer if it's not needed since it