diff --git a/src/keymap.c b/src/keymap.c
index efac410d317..7f5777c9251 100644
--- a/src/keymap.c
+++ b/src/keymap.c
@@ -3308,13 +3308,18 @@ describe_vector (Lisp_Object vector, Lisp_Object prefix, Lisp_Object args,
       if (this_shadowed)
 	{
 	  SET_PT (PT - 1);
-	  static char const fmt[] = "  (currently shadowed by `%s')";
-	  USE_SAFE_ALLOCA;
-	  char *buffer = SAFE_ALLOCA (sizeof fmt +
-				      SBYTES (SYMBOL_NAME (shadowed_by)));
-	  esprintf (buffer, fmt, SDATA (SYMBOL_NAME (shadowed_by)));
-	  insert_string (buffer);
-	  SAFE_FREE();
+	  if (SYMBOLP (shadowed_by))
+	    {
+	      static char const fmt[] = "  (currently shadowed by `%s')";
+	      USE_SAFE_ALLOCA;
+	      char *buffer =
+		SAFE_ALLOCA (sizeof fmt + SBYTES (SYMBOL_NAME (shadowed_by)));
+	      esprintf (buffer, fmt, SDATA (SYMBOL_NAME (shadowed_by)));
+	      insert_string (buffer);
+	      SAFE_FREE();
+	    }
+	  else	/* Could be a keymap, a lambda, or a keyboard macro.  */
+	    insert_string ("  (currently shadowed)");
 	  SET_PT (PT + 1);
 	}
     }