2 files changed, 11 insertions, 1 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 3acf12e4483..e16da43761f 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,7 @@
+2012-06-08  Stefan Monnier  <monnier@iro.umontreal.ca>
+
+        * eval.c (Fmacroexpand): Stop if the macro returns the same form.
+
 2012-06-07  Paul Eggert  <eggert@cs.ucla.edu>
 
         * doprnt.c (doprnt): Truncate multibyte char correctly.
diff --git a/src/eval.c b/src/eval.c
index 1da841a4073..85ff3ae19e6 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -1020,7 +1020,13 @@ definitions to shadow the loaded ones for use in file byte-compilation.  */)
           if (NILP (expander))
             break;
         }
-      form = apply1 (expander, XCDR (form));
+      {
+        Lisp_Object newform = apply1 (expander, XCDR (form));
+        if (EQ (form, newform))
+          break;
+        else
+          form = newform;
+      }
     }
   return form;
 }