diff -r dd58f13a8eb4 -r eb85850d3eb7 src/HOL/Library/Nat_Infinity.thy
--- a/src/HOL/Library/Nat_Infinity.thy	Fri Nov 17 02:19:55 2006 +0100
+++ b/src/HOL/Library/Nat_Infinity.thy	Fri Nov 17 02:20:03 2006 +0100
@@ -28,7 +28,7 @@
 instance inat :: "{ord, zero}" ..
 
 definition
-  iSuc :: "inat => inat"
+  iSuc :: "inat => inat" where
   "iSuc i = (case i of Fin n => Fin (Suc n) | \<infinity> => \<infinity>)"
 
 defs (overloaded)