diff -r da3a43cdbe8d -r 528054ca23e3 src/Pure/old_goals.ML
--- a/src/Pure/old_goals.ML	Fri Oct 06 15:39:29 2006 +0200
+++ b/src/Pure/old_goals.ML	Sat Oct 07 01:30:58 2006 +0200
@@ -156,7 +156,7 @@
       val _ = Term.no_dummy_patterns horn handle TERM (msg, _) => error msg;
       val (As, B) = Logic.strip_horn horn;
       val atoms = atomic andalso
-            forall (fn t => not(Logic.is_implies t orelse Logic.is_all t)) As;
+            forall (fn t => not (can Logic.dest_implies t orelse Logic.is_all t)) As;
       val (As,B) = if atoms then ([],horn) else (As,B);
       val cAs = map (cterm_of thy) As;
       val prems = map (rewrite_rule rths o forall_elim_vars 0 o Thm.assume) cAs;