--- a/src/HOL/Tools/datatype_package.ML Wed Nov 22 10:20:18 2006 +0100
+++ b/src/HOL/Tools/datatype_package.ML Wed Nov 22 10:20:19 2006 +0100
@@ -883,10 +883,8 @@
val (weak_case_congs, thy8) = DatatypeAbsProofs.prove_weak_case_congs new_type_names
[descr] sorts thy7;
val (size_thms, thy9) =
- if Context.exists_name "Nat" thy8 then
- DatatypeAbsProofs.prove_size_thms false new_type_names
- [descr] sorts reccomb_names rec_thms thy8
- else ([], thy8);
+ DatatypeAbsProofs.prove_size_thms false new_type_names
+ [descr] sorts reccomb_names rec_thms thy8;
val ((_, [induction']), thy10) =
thy9