Index: /trunk/ccl/level-1/l1-streams.lisp
===================================================================
--- /trunk/ccl/level-1/l1-streams.lisp	(revision 5151)
+++ /trunk/ccl/level-1/l1-streams.lisp	(revision 5152)
@@ -2123,5 +2123,5 @@
     (report-bad-arg s 'string-output-stream))
   (let* ((string (string-stream-string s)))
-    (prog1 (coerce string 'simple-string)
+    (prog1 (ensure-simple-string string)
       (setf (fill-pointer string) 0))))