handles failures (sometimes you can't inject)

diff --git a/components/tactics/discriminationTactics.ml b/components/tactics/discriminationTactics.ml
index 5a25c00fa95fbf4b2d21a124b3fca2b3dd4df321..ccbf17ae643df6a099d7e99309da3c5356bd010e 100644 (file)
--- a/components/tactics/discriminationTactics.ml
+++ b/components/tactics/discriminationTactics.ml
@@ -25,7 +25,10 @@
 
 (* $Id$ *)
 
-let debug_print = fun _ -> ()
+let debug = false
+let debug_print = 
+  if debug then (fun x -> prerr_endline (Lazy.force x)) else (fun _ -> ())
+;;
 
 (* term ha tipo t1=t2; funziona solo se t1 e t2 hanno in testa costruttori
 diversi *)
@@ -220,7 +223,6 @@ let rec injection_tac ~first_time ~term ~liftno ~continuation =
  let module T = Tacticals in
  let module PST = ProofEngineStructuralRules in
  let module PET = ProofEngineTypes in
-(*  let prerr_endline s = prerr_endline (String.make liftno ' ' ^ s) in *)
  let are_convertible hd1 hd2 metasenv context = 
    fst (CR.are_convertible ~metasenv context hd1 hd2 CicUniv.empty_ugraph)
  in
@@ -232,7 +234,7 @@ let rec injection_tac ~first_time ~term ~liftno ~continuation =
   let termty,_ = 
     CicTypeChecker.type_of_aux' metasenv context term CicUniv.empty_ugraph
   in
-(*   prerr_endline ("\ninjection su: " ^ pp context termty); *)
+  debug_print (lazy ("\ninjection su: " ^ pp context termty)); 
   let tac =
     match termty with
     | C.Appl [(C.MutInd (equri, 0, [])) ; tty ; t1 ; t2] 
@@ -322,7 +324,6 @@ and injection1_tac ~term ~i ~liftno ~continuation =
  let module P = PrimitiveTactics in
  let module PET = ProofEngineTypes in
  let module T = Tacticals in
-(*  let prerr_endline s = prerr_endline (String.make liftno ' ' ^ s) in *)
  let give_name seed = function
    | C.Name _ as name -> name
    | C.Anonymous -> C.Name (incr seed; "y" ^ string_of_int !seed)
@@ -339,7 +340,7 @@ and injection1_tac ~term ~i ~liftno ~continuation =
   let termty,_ = 
     CicTypeChecker.type_of_aux' metasenv context term CicUniv.empty_ugraph
   in
-(*   prerr_endline ("\ninjection1 su : " ^ pp context termty); *)
+  debug_print (lazy ("\ninjection1 su : " ^ pp context termty)); 
   match termty with (* an equality *)
   | C.Appl [(C.MutInd (equri, 0, [])) ; tty ; t1 ; t2]
     when LibraryObjects.is_eq_URI equri -> 
@@ -405,10 +406,15 @@ and injection1_tac ~term ~i ~liftno ~continuation =
                | _, _ -> assert false
              in
              let abstracted_tty =
-               match CicSubstitution.lift paramsno tty with
+               let tty =
+                 List.fold_left (fun x y -> CicSubstitution.subst y x) tty left_params
+               in
+               (* non lift, ma subst coi left! *)
+               match S.lift 1 tty with
                | C.MutInd _ as tty' -> tty'
                | C.Appl l ->
                    let keep,abstract = HExtlib.split_nth (paramsno +1) l in
+                   let keep = List.map (S.lift paramsno) keep in
                    C.Appl (keep@mk_rels (List.length abstract))
                | _ -> assert false
              in
@@ -418,7 +424,7 @@ and injection1_tac ~term ~i ~liftno ~continuation =
                (* this is in general wrong, do as in cases_tac *)
                to_lambdas (skip_prods left_params ty)
                  (C.Lambda 
-                   (C.Name "x", abstracted_tty,
+                   (C.Name "cased", abstracted_tty,
                      (* here we should capture right parameters *)
                      (* 1 for his Lambda, one for the Lambda outside the match
                       * and then one for each to_lambda *)
@@ -428,7 +434,25 @@ and injection1_tac ~term ~i ~liftno ~continuation =
         | _ -> raise exn_discrnonind
       in
       let cutted = C.Appl [C.MutInd (equri,0,[]) ; tty' ; t1' ; t2'] in
-(*       prerr_endline ("CUT: " ^ pp context cutted); *)
+      let changed = 
+        C.Appl [ C.Lambda (C.Name "x", tty, 
+                  C.MutCase (turi,typeno,outtype,C.Rel 1,patterns)) ; t1]
+      in
+      (* check if cutted and changed are well typed and if t1' ~ changed *)
+      let go_on =
+        try
+          let _,g = CicTypeChecker.type_of_aux' metasenv context  cutted
+            CicUniv.empty_ugraph
+          in
+          let _,g = CicTypeChecker.type_of_aux' metasenv context changed g in
+          fst (CicReduction.are_convertible ~metasenv context  t1' changed g)
+        with
+        | CicTypeChecker.TypeCheckerFailure _ -> false
+      in
+      if not go_on then
+        PET.apply_tactic Tacticals.id_tac status
+      else
+        (debug_print (lazy ("CUT: " ^ pp context cutted)); 
         PET.apply_tactic   
           (T.thens ~start: (P.cut_tac cutted)
              ~continuations:
@@ -441,7 +465,7 @@ and injection1_tac ~term ~i ~liftno ~continuation =
                ;T.then_ 
                   ~start:(PET.mk_tactic 
                     (fun status ->    
-(*                       prerr_endline "riempo il cut"; *)
+                      debug_print (lazy "riempo il cut"); 
                       let (proof, goal) = status in
                       let _,metasenv,_,_, _ = proof in
                       let _,context,gty =CicUtil.lookup_meta goal metasenv in
@@ -451,25 +475,17 @@ and injection1_tac ~term ~i ~liftno ~continuation =
                         | (C.Appl (C.MutInd (_,_,_)::_::t::_)) -> t
                         | _ -> raise exn_injwronggoal
                       in
-                      let changed = 
-                        C.Appl [ 
-                          C.Lambda (C.Name "x", tty, 
-                            C.MutCase (turi,typeno,outtype,C.Rel 1,patterns))
-                          ; t1]
-                      in
-(*
-                      prerr_endline 
-                        ("metto questo: " ^ pp context changed);
-                      prerr_endline 
-                        ("al posto di questo: " ^ pp context new_t1');
-                      prerr_endline 
-                        ("nel goal: " ^ pp context gty);
-                      prerr_endline 
-                        ("nel contesto:\n" ^ CicPp.ppcontext context);
-                      prerr_endline 
-                      ("e poi rewrite con: "^pp context term);
-*)
-                        let rc = 
+                      debug_print 
+                        (lazy ("metto questo: " ^ pp context changed));
+                      debug_print 
+                        (lazy ("al posto di questo: " ^ pp context new_t1'));
+                      debug_print 
+                        (lazy ("nel goal: " ^ pp context gty));
+                      debug_print 
+                        (lazy ("nel contesto:\n" ^ CicPp.ppcontext context));
+                      debug_print 
+                        (lazy ("e poi rewrite con: "^pp context term));
+                      let rc = 
                         PET.apply_tactic 
                           (ReductionTactics.change_tac
                             ~pattern:(None, [], 
@@ -488,7 +504,7 @@ and injection1_tac ~term ~i ~liftno ~continuation =
                           term [])
                       ~continuation:EqualityTactics.reflexivity_tac)
                ])     
-          status
+          status)
    | _ -> raise exn_noneq
  in
   PET.mk_tactic (injection1_tac ~term ~i)