(set-variable): Use user-variable-p instead of symbolp.

Add the old variable value as 4th default-value arg of read-string.

diff --git a/lisp/simple.el b/lisp/simple.el
index 8f98b1cc9075ae593237e081fd3e7d4b53d28151..efe1559cb4df70b06ac43b529b84989d3da39b9e 100644 (file)
--- a/lisp/simple.el
+++ b/lisp/simple.el
@@ -4572,10 +4572,10 @@ in the definition is used to check that VALUE is valid.
 With a prefix argument, set VARIABLE to VALUE buffer-locally."
   (interactive
    (let* ((default-var (variable-at-point))
-          (var (if (symbolp default-var)
-                       (read-variable (format "Set variable (default %s): " default-var)
-                                      default-var)
-                     (read-variable "Set variable: ")))
+          (var (if (user-variable-p default-var)
+                  (read-variable (format "Set variable (default %s): " default-var)
+                                 default-var)
+                (read-variable "Set variable: ")))
          (minibuffer-help-form '(describe-variable var))
          (prop (get var 'variable-interactive))
           (obsolete (car (get var 'byte-obsolete-variable)))
@@ -4600,7 +4600,8 @@ With a prefix argument, set VARIABLE to VALUE buffer-locally."
                                             arg))
                    (read
                     (read-string prompt nil
-                                 'set-variable-value-history))))))
+                                 'set-variable-value-history
+                                (format "%S" (symbol-value var))))))))
      (list var val current-prefix-arg)))
 
   (and (custom-variable-p variable)