--- a/src/HOL/Tools/Predicate_Compile/predicate_compile_core.ML Fri Sep 24 10:27:11 2010 +0200
+++ b/src/HOL/Tools/Predicate_Compile/predicate_compile_core.ML Fri Sep 24 11:36:28 2010 +0200
@@ -431,7 +431,8 @@
fun check_matches_type ctxt predname T ms =
let
fun check (m as Fun (m1, m2)) (Type("fun", [T1,T2])) = check m1 T1 andalso check m2 T2
- | check m (Type("fun", _)) = false
+ | check m (T as Type("fun", _)) =
+ if body_type T = @{typ bool} then false else (m = Input orelse m = Output)
| check (Pair (m1, m2)) (Type (@{type_name Product_Type.prod}, [T1, T2])) =
check m1 T1 andalso check m2 T2
| check Input T = true