diff -r 584077922200 -r 302104d8366b src/HOL/Tools/inductive.ML
--- a/src/HOL/Tools/inductive.ML	Wed Nov 12 11:39:27 2014 +0100
+++ b/src/HOL/Tools/inductive.ML	Wed Nov 12 18:18:38 2014 +0100
@@ -585,7 +585,7 @@
   let
     val thmss =
       map snd args
-      |> burrow (grouped 10 Par_List.map (mk_cases lthy o prep_prop lthy));
+      |> burrow (grouped 10 Par_List.map_independent (mk_cases lthy o prep_prop lthy));
     val facts =
       map2 (fn ((a, atts), _) => fn thms => ((a, map (prep_att lthy) atts), [(thms, [])]))
         args thmss;