diff -r d1c9bf0f8ae8 -r ba7ff3f9527a src/HOL/Tools/inductive_codegen.ML
--- a/src/HOL/Tools/inductive_codegen.ML	Thu Oct 22 09:50:29 2009 +0200
+++ b/src/HOL/Tools/inductive_codegen.ML	Thu Oct 22 14:08:01 2009 +0200
@@ -625,7 +625,7 @@
 fun conv_ntuple fs ts p =
   let
     val k = length fs;
-    val xs = map (fn i => str ("x" ^ string_of_int i)) (0 upto k);
+    val xs = map_range (fn i => str ("x" ^ string_of_int i)) (k + 1);
     val xs' = map (fn Bound i => nth xs (k - i)) ts;
     fun conv xs js =
       if js mem fs then