2 files changed, 10 insertions, 2 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 99e1b6a90f1..1f96b0aaaa4 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,8 @@
+2006-04-30  Richard Stallman  <rms@gnu.org>
+
+        * keymap.c (Fdefine_key): Improve error message
+        when KEY begins with a non-prefix key.
+
 2006-04-30  Martin Rudalics  <rudalics@gmx.at>  (tiny change)
 
         * syntax.c (Fforward_comment): Don't forget to break out of the loop
diff --git a/src/keymap.c b/src/keymap.c
index 66f17178d5b..4f8343bf5cf 100644
--- a/src/keymap.c
+++ b/src/keymap.c
@@ -1193,8 +1193,11 @@ binding KEY to DEF is added at the front of KEYMAP.  */)
       if (!CONSP (keymap))
         /* We must use Fkey_description rather than just passing key to
            error; key might be a vector, not a string.  */
-        error ("Key sequence %s uses invalid prefix characters",
-               SDATA (Fkey_description (key, Qnil)));
+        error ("Key sequence %s starts with non-prefix key %s",
+               SDATA (Fkey_description (key, Qnil)),
+               SDATA (Fkey_description (Fsubstring (key, make_number (0),
+                                                    make_number (idx)),
+                                        Qnil)));
     }
 }