adding type inference for disambiguation annotations in code equation

--- a/src/Tools/Code/code_thingol.ML	Wed Sep 07 13:51:32 2011 +0200
+++ b/src/Tools/Code/code_thingol.ML	Wed Sep 07 13:51:34 2011 +0200
@@ -609,6 +609,43 @@
       (err_typ ^ "\n" ^ err_class)
   end;
 
+(* inference of type annotations for disambiguation with type classes *)
+
+
+fun annotate_term (Const (c', T'), Const (c, T)) tvar_names =
+    let
+      val tvar_names' = Term.add_tvar_namesT T' tvar_names
+    in
+      (Const (c, if eq_set (op =) (tvar_names, tvar_names') then T else Type("", [T])), tvar_names')
+    end
+  | annotate_term (t1 $ u1, t $ u) tvar_names =
+    let
+      val (u', tvar_names') = annotate_term (u1, u) tvar_names
+      val (t', tvar_names'') = annotate_term (t1, t) tvar_names'    
+    in
+      (t' $ u', tvar_names'')
+    end
+  | annotate_term (Abs (_, _, t1) , Abs (x, T, t)) tvar_names =
+    apfst (fn t => Abs (x, T, t)) (annotate_term (t1, t) tvar_names)
+  | annotate_term (_, t) tvar_names = (t, tvar_names)
+
+fun annotate_eqns thy eqns = 
+  let
+    val ctxt = ProofContext.init_global thy
+    val erase = map_types (fn _ => Type_Infer.anyT [])
+    val reinfer = singleton (Type_Infer_Context.infer_types ctxt)
+    fun add_annotations ((args, (rhs, some_abs)), (SOME th, proper)) =
+      let
+        val (lhs, drhs) = Logic.dest_equals (prop_of (Thm.unvarify_global th))
+        val drhs' = snd (Logic.dest_equals (reinfer (Logic.mk_equals (lhs, erase drhs))))
+        val (rhs', _) = annotate_term (drhs', rhs) []
+     in
+        ((args, (rhs', some_abs)), (SOME th, proper))
+     end
+     | add_annotations eqn = eqn
+  in
+    map add_annotations eqns
+  end;
 
 (* translation *)