--- a/src/HOL/Tools/Quickcheck/quickcheck_common.ML Thu Dec 01 22:14:35 2011 +0100
+++ b/src/HOL/Tools/Quickcheck/quickcheck_common.ML Thu Dec 01 22:14:35 2011 +0100
@@ -274,7 +274,7 @@
@{term "Quickcheck.catch_match :: (bool * term list) option => (bool * term list) option => (bool * term list) option"}
$ (@{term "If :: bool => (bool * term list) option => (bool * term list) option => (bool * term list) option"}
$ cond $ then_t $ else_t true)
- $ (if Config.get ctxt Quickcheck.potential then else_t false else @{term "None :: term list option"});
+ $ (if Config.get ctxt Quickcheck.potential then else_t false else @{term "None :: (bool * term list) option"});
fun collect_results f [] results = results
| collect_results f (t :: ts) results =