identity coercions are not really inserted, just used as hints for unification

[helm.git] / helm / software / components / cic_unification / cicRefine.ml

diff --git a/helm/software/components/cic_unification/cicRefine.ml b/helm/software/components/cic_unification/cicRefine.ml
index bde5d63e413978703bf8ef0d58a9908f478d1d34..a2c7707493bb82baafc0561e7f6418a02ea41483 100644 (file)
--- a/helm/software/components/cic_unification/cicRefine.ml
+++ b/helm/software/components/cic_unification/cicRefine.ml
@@ -405,6 +405,37 @@ and type_of_aux' ?(clean_dummy_dependent_types=true) ?(localization_tbl = Cic.Ci
             let te',inferredty,subst'',metasenv'',ugraph2 =
               type_of_aux subst' metasenv' context te ugraph1
             in
+            let rec count_prods context ty =
+              match CicReduction.whd context ~subst:subst'' ty with
+              | Cic.Prod (n,s,t) -> 
+                 1 + count_prods (Some (n,Cic.Decl s)::context) t
+              | _ -> 0
+            in
+            let exp_prods = count_prods context ty' in
+            let inf_prods = count_prods context inferredty in
+            let te', inferredty, metasenv'', subst'', ugraph2 =
+               let rec aux t m s ug it = function
+                 | 0 -> t,it,m,s,ug
+                 | n ->
+                      match CicReduction.whd context ~subst:s it with
+                      | Cic.Prod (_,src,tgt) -> 
+                          let newmeta, metaty, s, m, ug =
+                            type_of_aux s m context (Cic.Implicit None) ug
+                          in
+                          let s,m,ug = 
+                            fo_unif_subst s context m metaty src ug
+                          in
+                          let t =
+                            match t with
+                            | Cic.Appl l -> Cic.Appl (l @ [newmeta])
+                            | _ -> Cic.Appl [t;newmeta]
+                          in
+                          aux t m s ug (CicSubstitution.subst newmeta tgt) (n-1)
+                      | _ -> t,it,m,s,ug     
+               in
+                 aux te' metasenv'' subst'' ugraph2 inferredty
+                   (max 0 (inf_prods - exp_prods))
+            in
             let (te', ty'), subst''',metasenv''',ugraph3 =
               coerce_to_something true localization_tbl te' inferredty ty'
                 subst'' metasenv'' context ugraph2
@@ -1104,7 +1135,7 @@ and type_of_aux' ?(clean_dummy_dependent_types=true) ?(localization_tbl = Cic.Ci
         | (C.Sort (C.CProp t1), C.Sort (C.Type t2)) -> 
             let t' = CicUniv.fresh() in 
              (try
-              let ugraph1 = CicUniv.add_gt t' t1 ugraph in
+              let ugraph1 = CicUniv.add_ge t' t1 ugraph in
               let ugraph2 = CicUniv.add_ge t' t2 ugraph1 in
                 C.Sort (C.Type t'),subst,metasenv,ugraph2
               with
@@ -1160,7 +1191,7 @@ and type_of_aux' ?(clean_dummy_dependent_types=true) ?(localization_tbl = Cic.Ci
       | CoercGraph.SomeCoercion candidates -> 
          let selected =
            HExtlib.list_findopt
-             (function (metasenv,last,c) ->
+             (fun (metasenv,last,c) _ ->
                match c with 
                | c when not (CoercGraph.is_composite c) -> 
                    debug_print (lazy ("\nNot a composite.."^CicPp.ppterm c));
@@ -1308,12 +1339,13 @@ and type_of_aux' ?(clean_dummy_dependent_types=true) ?(localization_tbl = Cic.Ci
                "Fixing arity of: "^ pp he ^ "\n that has type: "^ pp hetype^
                "\n but is applyed to: " ^ String.concat ";" 
                (List.map (fun (t,_)->pp t) args_bo_and_ty)); (*}}}*)
+              let error = ref None in
               let possible_fixes = 
                fix_arity (List.length args) metasenv context subst he hetype
                 ugraph in
               match
                 HExtlib.list_findopt
-                 (fun (he,hetype,subst,metasenv,ugraph) ->
+                 (fun (he,hetype,subst,metasenv,ugraph) _ ->
                    (* {{{ *)debug_print (lazy ("Try fix: "^
                     CicMetaSubst.ppterm_in_context ~metasenv subst he context));
                    debug_print (lazy (" of type: "^
@@ -1325,14 +1357,18 @@ and type_of_aux' ?(clean_dummy_dependent_types=true) ?(localization_tbl = Cic.Ci
                    with
                     | RefineFailure _ | Uncertain _
                     | HExtlib.Localized (_,RefineFailure _)
-                    | HExtlib.Localized (_,Uncertain _) -> None)
+                    | HExtlib.Localized (_,Uncertain _) as exn ->
+                       error := Some exn; None)
                 possible_fixes
               with
               | Some x -> x
               | None ->
-                 raise 
-                  (MoreArgsThanExpected
-                    (List.length args, RefineFailure (lazy "")))
+                 match !error with
+                    None ->
+                     raise 
+                      (MoreArgsThanExpected
+                        (List.length args, RefineFailure (lazy "")))
+                  | Some exn -> raise exn
     in
     (* first we check if we are in the simple case of a meta closed term *)
     let subst,metasenv,ugraph1,hetype',he,args_bo_and_ty =
@@ -1408,11 +1444,19 @@ and type_of_aux' ?(clean_dummy_dependent_types=true) ?(localization_tbl = Cic.Ci
                 let newt,newhety,subst,metasenv,ugraph = 
                  type_of_aux subst metasenv context c ugraph in
                 let newt, newty, subst, metasenv, ugraph = 
-                 avoid_double_coercion context subst metasenv ugraph newt expty 
+                  avoid_double_coercion context subst metasenv ugraph newt
+                    expty 
                 in
                 let subst,metasenv,ugraph = 
-                  fo_unif_subst subst context metasenv newhety expty ugraph in
-                 Some ((newt,newty), subst, metasenv, ugraph)
+                  fo_unif_subst subst context metasenv newhety expty ugraph
+                in
+                let b, ugraph =
+                  CicReduction.are_convertible ~subst context infty expty ugraph
+                in
+                if b then 
+                  Some ((t,infty), subst, metasenv, ugraph)
+                else 
+                  Some ((newt,newty), subst, metasenv, ugraph)
                with 
                | Uncertain _ -> uncertain := true; None
                | RefineFailure _ -> None)
@@ -1937,10 +1981,13 @@ let typecheck metasenv uri obj ~localization_tbl =
      let metasenv = CicMetaSubst.apply_subst_metasenv subst metasenv in
       Cic.Constant (name,Some bo',ty',args,attrs),metasenv,ugraph
   | Cic.Constant (name,None,ty,args,attrs) ->
-     let ty',_,metasenv,ugraph =
+     let ty',sort,metasenv,ugraph =
       type_of_aux' ~localization_tbl metasenv [] ty ugraph
      in
-      Cic.Constant (name,None,ty',args,attrs),metasenv,ugraph
+      (match CicReduction.whd [] sort with
+          Cic.Sort _
+        | Cic.Meta _ -> Cic.Constant (name,None,ty',args,attrs),metasenv,ugraph
+        | _ -> raise (RefineFailure (lazy "")))
   | Cic.CurrentProof (name,metasenv',bo,ty,args,attrs) ->
      assert (metasenv' = metasenv);
      (* Here we do not check the metasenv for correctness *)
@@ -1949,7 +1996,7 @@ let typecheck metasenv uri obj ~localization_tbl =
      let ty',sort,metasenv,ugraph =
       type_of_aux' ~localization_tbl metasenv [] ty ugraph in
      begin
-      match sort with
+       match CicReduction.whd ~delta:true [] sort with
          Cic.Sort _
        (* instead of raising Uncertain, let's hope that the meta will become
           a sort *)