--- a/src/HOL/Tools/datatype_aux.ML Wed Nov 02 16:37:39 2005 +0100
+++ b/src/HOL/Tools/datatype_aux.ML Wed Nov 02 23:59:49 2005 +0100
@@ -238,7 +238,7 @@
NONE => DtType (tname, map (dtyp_of_typ new_dts) Ts)
| SOME vs => if map (try dest_TFree) Ts = map SOME vs then
DtRec (find_index (curry op = tname o fst) new_dts)
- else error ("Illegal occurence of recursive type " ^ tname));
+ else error ("Illegal occurrence of recursive type " ^ tname));
fun typ_of_dtyp descr sorts (DtTFree a) = TFree (a, (the o AList.lookup (op =) sorts) a)
| typ_of_dtyp descr sorts (DtRec i) =