src/Tools/quickcheck.ML

   let
     val ctxt = Proof.context_of state;
     val thy = Proof.theory_of state;
     fun strip (Const ("all", _) $ Abs (_, _, t)) = strip t
       | strip t = t;
-    val (_, st) = Proof.flat_goal state;
+    val (_, (_, st)) = Proof.get_goal state;
     val (gi, frees) = Logic.goal_params (prop_of st) i;
     val gi' = Logic.list_implies (assms, subst_bounds (frees, strip gi))
       |> monomorphic_term thy insts default_T
       |> ObjectLogic.atomize_term thy;
   in test_term ctxt quiet generator_name size iterations gi' end;