* http://cs.unibo.it/helm/.
*)
-exception UnificationFailed;;
-exception Free;;
-exception OccurCheck;;
-exception RelToHiddenHypothesis;;
-exception OpenTerm;;
+open Printf
-(**** DELIFT ****)
+exception AssertFailure of string;;
+exception UnificationFailure of string;;
-(* the delift function takes in input an ordered list of optional terms *)
-(* [t1,...,tn] and a term t, and substitutes every tk = Some (rel(nk)) with *)
-(* rel(k). Typically, the list of optional terms is the explicit substitution *)
-(* that is applied to a metavariable occurrence and the result of the delift *)
-(* function is a term the implicit variable can be substituted with to make *)
-(* the term [t] unifiable with the metavariable occurrence. *)
-(* In general, the problem is undecidable if we consider equivalence in place *)
-(* of alpha convertibility. Our implementation, though, is even weaker than *)
-(* alpha convertibility, since it replace the term [tk] if and only if [tk] *)
-(* is a Rel (missing all the other cases). Does this matter in practice? *)
+let debug_print = prerr_endline
-exception NotInTheList;;
-
-let position n =
- let rec aux k =
- function
- [] -> raise NotInTheList
- | (Some (Cic.Rel m))::_ when m=n -> k
- | _::tl -> aux (k+1) tl in
- aux 1
-;;
-
-(*CSC: this restriction function is utterly wrong, since it does not check *)
-(*CSC: that the variable that is going to be restricted does not occur free *)
-(*CSC: in a part of the sequent that is not going to be restricted. *)
-(*CSC: In particular, the whole approach is wrong; if restriction can fail *)
-(*CSC: (as indeed it is the case), we can not collect all the restrictions *)
-(*CSC: and restrict everything at the end ;-( *)
-let restrict to_be_restricted =
- let rec erase i n =
- function
- [] -> []
- | _::tl when List.mem (n,i) to_be_restricted ->
- None::(erase (i+1) n tl)
- | he::tl -> he::(erase (i+1) n tl) in
- let rec aux =
- function
- [] -> []
- | (n,context,t)::tl -> (n,erase 1 n context,t)::(aux tl) in
- aux
-;;
-
-
-(*CSC: maybe we should rename delift in abstract, as I did in my dissertation *)
-let delift context metasenv l t =
- let module S = CicSubstitution in
- let to_be_restricted = ref [] in
- let rec deliftaux k =
- let module C = Cic in
- function
- C.Rel m ->
- if m <=k then
- C.Rel m (*CSC: che succede se c'e' un Def? Dovrebbe averlo gia' *)
- (*CSC: deliftato la regola per il LetIn *)
- (*CSC: FALSO! La regola per il LetIn non lo fa *)
- else
- (match List.nth context (m-k-1) with
- Some (_,C.Def (t,_)) ->
- (*CSC: Hmmm. This bit of reduction is not in the spirit of *)
- (*CSC: first order unification. Does it help or does it harm? *)
- deliftaux k (S.lift m t)
- | Some (_,C.Decl t) ->
- (*CSC: The following check seems to be wrong! *)
- (*CSC: B:Set |- ?2 : Set *)
- (*CSC: A:Set ; x:?2[A/B] |- ?1[x/A] =?= x *)
- (*CSC: Why should I restrict ?2 over B? The instantiation *)
- (*CSC: ?1 := A is perfectly reasonable and well-typed. *)
- (*CSC: Thus I comment out the following two lines that *)
- (*CSC: are the incriminated ones. *)
- (*(* It may augment to_be_restricted *)
- ignore (deliftaux k (S.lift m t)) ;*)
- (*CSC: end of bug commented out *)
- C.Rel ((position (m-k) l) + k)
- | None -> raise RelToHiddenHypothesis)
- | C.Var (uri,exp_named_subst) ->
- let exp_named_subst' =
- List.map (function (uri,t) -> uri,deliftaux k t) exp_named_subst
- in
- C.Var (uri,exp_named_subst')
- | C.Meta (i, l1) as t ->
- let rec deliftl j =
- function
- [] -> []
- | None::tl -> None::(deliftl (j+1) tl)
- | (Some t)::tl ->
- let l1' = (deliftl (j+1) tl) in
- try
- Some (deliftaux k t)::l1'
- with
- RelToHiddenHypothesis
- | NotInTheList ->
- to_be_restricted := (i,j)::!to_be_restricted ; None::l1'
- in
- let l' = deliftl 1 l1 in
- C.Meta(i,l')
- | C.Sort _ as t -> t
- | C.Implicit as t -> t
- | C.Cast (te,ty) -> C.Cast (deliftaux k te, deliftaux k ty)
- | C.Prod (n,s,t) -> C.Prod (n, deliftaux k s, deliftaux (k+1) t)
- | C.Lambda (n,s,t) -> C.Lambda (n, deliftaux k s, deliftaux (k+1) t)
- | C.LetIn (n,s,t) -> C.LetIn (n, deliftaux k s, deliftaux (k+1) t)
- | C.Appl l -> C.Appl (List.map (deliftaux k) l)
- | C.Const (uri,exp_named_subst) ->
- let exp_named_subst' =
- List.map (function (uri,t) -> uri,deliftaux k t) exp_named_subst
- in
- C.Const (uri,exp_named_subst')
- | C.MutInd (uri,typeno,exp_named_subst) ->
- let exp_named_subst' =
- List.map (function (uri,t) -> uri,deliftaux k t) exp_named_subst
- in
- C.MutInd (uri,typeno,exp_named_subst')
- | C.MutConstruct (uri,typeno,consno,exp_named_subst) ->
- let exp_named_subst' =
- List.map (function (uri,t) -> uri,deliftaux k t) exp_named_subst
- in
- C.MutConstruct (uri,typeno,consno,exp_named_subst')
- | C.MutCase (sp,i,outty,t,pl) ->
- C.MutCase (sp, i, deliftaux k outty, deliftaux k t,
- List.map (deliftaux k) pl)
- | C.Fix (i, fl) ->
- let len = List.length fl in
- let liftedfl =
- List.map
- (fun (name, i, ty, bo) ->
- (name, i, deliftaux k ty, deliftaux (k+len) bo))
- fl
- in
- C.Fix (i, liftedfl)
- | C.CoFix (i, fl) ->
- let len = List.length fl in
- let liftedfl =
- List.map
- (fun (name, ty, bo) -> (name, deliftaux k ty, deliftaux (k+len) bo))
- fl
- in
- C.CoFix (i, liftedfl)
- in
- let res =
- try
- deliftaux 0 t
- with
- NotInTheList ->
- (* This is the case where we fail even first order unification. *)
- (* The reason is that our delift function is weaker than first *)
- (* order (in the sense of alpha-conversion). See comment above *)
- (* related to the delift function. *)
-prerr_endline "!!!!!!!!!!! First Order UnificationFailed, but maybe it could have been successful even in a first order setting (no conversion, only alpha convertibility)! Please, implement a better delift function !!!!!!!!!!!!!!!!" ;
- raise UnificationFailed
- in
- res, restrict !to_be_restricted metasenv
-;;
-
-(**** END OF DELIFT ****)
-
-type substitution = (int * Cic.term) list
+let type_of_aux' metasenv subst context term =
+ try
+ CicMetaSubst.type_of_aux' metasenv subst context term
+ with CicMetaSubst.MetaSubstFailure msg ->
+ raise (AssertFailure
+ ((sprintf
+ "Type checking error: %s in context\n%s.\nException: %s.\nBroken invariant: unification must be invoked only on well typed terms"
+ (CicPp.ppterm (CicMetaSubst.apply_subst subst term))
+ (CicMetaSubst.ppcontext subst context) msg)))
(* NUOVA UNIFICAZIONE *)
(* A substitution is a (int * Cic.term) list that associates a
fo_unif_new takes a metasenv, a context, two terms t1 and t2 and gives back
a new substitution which is _NOT_ unwinded. It must be unwinded before
applying it. *)
-
+
let rec fo_unif_subst subst context metasenv t1 t2 =
let module C = Cic in
let module R = CicReduction in
R.are_convertible context t1' t2'
) true ln lm
in
- if ok then subst,metasenv else raise UnificationFailed
+ if ok then
+ subst,metasenv
+ else
+ raise (UnificationFailure (sprintf
+ "Error trying to unify %s with %s: the algorithm only tried to check convertibility of the two substitutions"
+ (CicPp.ppterm t1) (CicPp.ppterm t2)))
| (C.Meta (n,l), C.Meta (m,_)) when n>m ->
fo_unif_subst subst context metasenv t2 t1
| (C.Meta (n,l), t)
let lifted_oldt = S.lift_meta l oldt in
fo_unif_subst subst context metasenv lifted_oldt t
with Not_found ->
- let t',metasenv' = delift context metasenv l t in
+ let t',metasenv' = CicMetaSubst.delift context metasenv l t in
(n, t')::subst, metasenv'
in
let (_,_,meta_type) =
List.find (function (m,_,_) -> m=n) metasenv' in
- let tyt = CicTypeChecker.type_of_aux' metasenv' context t in
+ let tyt = type_of_aux' metasenv' subst' context t in
fo_unif_subst subst' context metasenv' (S.lift_meta l meta_type) tyt
| (C.Var (uri1,exp_named_subst1),C.Var (uri2,exp_named_subst2))
| (C.Const (uri1,exp_named_subst1),C.Const (uri2,exp_named_subst2)) ->
fo_unif_subst_exp_named_subst subst context metasenv
exp_named_subst1 exp_named_subst2
else
- raise UnificationFailed
+ raise (UnificationFailure (sprintf
+ "Can't unify %s with %s due to different constants"
+ (CicPp.ppterm t1) (CicPp.ppterm t1)))
| C.MutInd (uri1,i1,exp_named_subst1),C.MutInd (uri2,i2,exp_named_subst2) ->
if UriManager.eq uri1 uri2 && i1 = i2 then
fo_unif_subst_exp_named_subst subst context metasenv
exp_named_subst1 exp_named_subst2
else
- raise UnificationFailed
+ raise (UnificationFailure (sprintf
+ "Can't unify %s with %s due to different inductive principles"
+ (CicPp.ppterm t1) (CicPp.ppterm t1)))
| C.MutConstruct (uri1,i1,j1,exp_named_subst1),
C.MutConstruct (uri2,i2,j2,exp_named_subst2) ->
if UriManager.eq uri1 uri2 && i1 = i2 && j1 = j2 then
fo_unif_subst_exp_named_subst subst context metasenv
exp_named_subst1 exp_named_subst2
else
- raise UnificationFailed
- | (C.Rel _, _)
- | (_, C.Rel _)
- | (C.Sort _ ,_)
- | (_, C.Sort _)
- | (C.Implicit, _)
- | (_, C.Implicit) ->
- if R.are_convertible context t1 t2 then
- subst, metasenv
- else
- raise UnificationFailed
+ raise (UnificationFailure (sprintf
+ "Can't unify %s with %s due to different inductive constructors"
+ (CicPp.ppterm t1) (CicPp.ppterm t1)))
+ | (C.Implicit, _) | (_, C.Implicit) -> assert false
| (C.Cast (te,ty), t2) -> fo_unif_subst subst context metasenv te t2
| (t1, C.Cast (te,ty)) -> fo_unif_subst subst context metasenv t1 te
| (C.Prod (n1,s1,t1), C.Prod (_,s2,t2)) ->
fo_unif_l subst' metasenv' (l1,l2)
in
fo_unif_l subst metasenv (lr1, lr2)
- | (C.Const _, _)
- | (_, C.Const _)
- | (C.MutInd _, _)
- | (_, C.MutInd _)
- | (C.MutConstruct _, _)
- | (_, C.MutConstruct _) ->
- if R.are_convertible context t1 t2 then
- subst, metasenv
- else
- raise UnificationFailed
| (C.MutCase (_,_,outt1,t1,pl1), C.MutCase (_,_,outt2,t2,pl2))->
let subst', metasenv' =
fo_unif_subst subst context metasenv outt1 outt2 in
(function (subst,metasenv) ->
fo_unif_subst subst context metasenv
) (subst'',metasenv'') pl1 pl2
- | (C.Fix _, _)
- | (_, C.Fix _)
- | (C.CoFix _, _)
- | (_, C.CoFix _) ->
+ | (C.Rel _, _) | (_, C.Rel _)
+ | (C.Sort _ ,_) | (_, C.Sort _)
+ | (C.Const _, _) | (_, C.Const _)
+ | (C.MutInd _, _) | (_, C.MutInd _)
+ | (C.MutConstruct _, _) | (_, C.MutConstruct _)
+ | (C.Fix _, _) | (_, C.Fix _)
+ | (C.CoFix _, _) | (_, C.CoFix _) ->
if R.are_convertible context t1 t2 then
subst, metasenv
else
- raise UnificationFailed
+ raise (UnificationFailure (sprintf
+ "Can't unify %s with %s because they are not convertible"
+ (CicPp.ppterm t1) (CicPp.ppterm t2)))
| (_,_) ->
if R.are_convertible context t1 t2 then
subst, metasenv
else
- raise UnificationFailed
+ raise (UnificationFailure (sprintf
+ "Can't unify %s with %s because they are not convertible"
+ (CicPp.ppterm t1) (CicPp.ppterm t2)))
and fo_unif_subst_exp_named_subst subst context metasenv
exp_named_subst1 exp_named_subst2
with
e ->
let uri = UriManager.uri_of_string "cic:/dummy.var" in
-prerr_endline ("@@@: " ^ CicPp.ppterm (Cic.Var (uri,exp_named_subst1)) ^
+debug_print ("@@@: " ^ CicPp.ppterm (Cic.Var (uri,exp_named_subst1)) ^
" <==> " ^ CicPp.ppterm (Cic.Var (uri,exp_named_subst2))) ; raise e
-;;
-
-let unwind metasenv subst unwinded t =
- let unwinded = ref unwinded in
- let frozen = ref [] in
- let rec um_aux metasenv =
- let module C = Cic in
- let module S = CicSubstitution in
- function
- C.Rel _ as t -> t,metasenv
- | C.Var _ as t -> t,metasenv
- | C.Meta (i,l) ->
- (try
- S.lift_meta l (List.assoc i !unwinded), metasenv
- with Not_found ->
- if List.mem i !frozen then raise OccurCheck
- else
- let saved_frozen = !frozen in
- frozen := i::!frozen ;
- let res =
- try
- let t = List.assoc i subst in
- let t',metasenv' = um_aux metasenv t in
- let _,metasenv'' =
- let (_,canonical_context,_) =
- List.find (function (m,_,_) -> m=i) metasenv
- in
- delift canonical_context metasenv' l t'
- in
- unwinded := (i,t')::!unwinded ;
- S.lift_meta l t', metasenv'
- with
- Not_found ->
- (* not constrained variable, i.e. free in subst*)
- let l',metasenv' =
- List.fold_right
- (fun t (tl,metasenv) ->
- match t with
- None -> None::tl,metasenv
- | Some t ->
- let t',metasenv' = um_aux metasenv t in
- (Some t')::tl, metasenv'
- ) l ([],metasenv)
- in
- C.Meta (i,l'), metasenv'
- in
- frozen := saved_frozen ;
- res
- )
- | C.Sort _
- | C.Implicit as t -> t,metasenv
- | C.Cast (te,ty) ->
- let te',metasenv' = um_aux metasenv te in
- let ty',metasenv'' = um_aux metasenv' ty in
- C.Cast (te',ty'),metasenv''
- | C.Prod (n,s,t) ->
- let s',metasenv' = um_aux metasenv s in
- let t',metasenv'' = um_aux metasenv' t in
- C.Prod (n, s', t'), metasenv''
- | C.Lambda (n,s,t) ->
- let s',metasenv' = um_aux metasenv s in
- let t',metasenv'' = um_aux metasenv' t in
- C.Lambda (n, s', t'), metasenv''
- | C.LetIn (n,s,t) ->
- let s',metasenv' = um_aux metasenv s in
- let t',metasenv'' = um_aux metasenv' t in
- C.LetIn (n, s', t'), metasenv''
- | C.Appl (he::tl) ->
- let tl',metasenv' =
- List.fold_right
- (fun t (tl,metasenv) ->
- let t',metasenv' = um_aux metasenv t in
- t'::tl, metasenv'
- ) tl ([],metasenv)
- in
- begin
- match um_aux metasenv' he with
- (C.Appl l, metasenv'') -> C.Appl (l@tl'),metasenv''
- | (he', metasenv'') -> C.Appl (he'::tl'),metasenv''
- end
- | C.Appl _ -> assert false
- | C.Const (uri,exp_named_subst) ->
- let exp_named_subst', metasenv' =
- List.fold_right
- (fun (uri,t) (tl,metasenv) ->
- let t',metasenv' = um_aux metasenv t in
- (uri,t')::tl, metasenv'
- ) exp_named_subst ([],metasenv)
- in
- C.Const (uri,exp_named_subst'),metasenv'
- | C.MutInd (uri,typeno,exp_named_subst) ->
- let exp_named_subst', metasenv' =
- List.fold_right
- (fun (uri,t) (tl,metasenv) ->
- let t',metasenv' = um_aux metasenv t in
- (uri,t')::tl, metasenv'
- ) exp_named_subst ([],metasenv)
- in
- C.MutInd (uri,typeno,exp_named_subst'),metasenv'
- | C.MutConstruct (uri,typeno,consno,exp_named_subst) ->
- let exp_named_subst', metasenv' =
- List.fold_right
- (fun (uri,t) (tl,metasenv) ->
- let t',metasenv' = um_aux metasenv t in
- (uri,t')::tl, metasenv'
- ) exp_named_subst ([],metasenv)
- in
- C.MutConstruct (uri,typeno,consno,exp_named_subst'),metasenv'
- | C.MutCase (sp,i,outty,t,pl) ->
- let outty',metasenv' = um_aux metasenv outty in
- let t',metasenv'' = um_aux metasenv' t in
- let pl',metasenv''' =
- List.fold_right
- (fun p (pl,metasenv) ->
- let p',metasenv' = um_aux metasenv p in
- p'::pl, metasenv'
- ) pl ([],metasenv'')
- in
- C.MutCase (sp, i, outty', t', pl'),metasenv'''
- | C.Fix (i, fl) ->
- let len = List.length fl in
- let liftedfl,metasenv' =
- List.fold_right
- (fun (name, i, ty, bo) (fl,metasenv) ->
- let ty',metasenv' = um_aux metasenv ty in
- let bo',metasenv'' = um_aux metasenv' bo in
- (name, i, ty', bo')::fl,metasenv''
- ) fl ([],metasenv)
- in
- C.Fix (i, liftedfl),metasenv'
- | C.CoFix (i, fl) ->
- let len = List.length fl in
- let liftedfl,metasenv' =
- List.fold_right
- (fun (name, ty, bo) (fl,metasenv) ->
- let ty',metasenv' = um_aux metasenv ty in
- let bo',metasenv'' = um_aux metasenv' bo in
- (name, ty', bo')::fl,metasenv''
- ) fl ([],metasenv)
- in
- C.CoFix (i, liftedfl),metasenv'
- in
- let t',metasenv' = um_aux metasenv t in
- t',metasenv',!unwinded
-;;
-
-(* apply_subst_reducing subst (Some (mtr,reductions_no)) t *)
-(* performs as (apply_subst subst t) until it finds an application of *)
-(* (META [meta_to_reduce]) that, once unwinding is performed, creates *)
-(* a new beta-redex; in this case up to [reductions_no] consecutive *)
-(* beta-reductions are performed. *)
-(* Hint: this function is usually called when [reductions_no] *)
-(* eta-expansions have been performed and the head of the new *)
-(* application has been unified with (META [meta_to_reduce]): *)
-(* during the unwinding the eta-expansions are undone. *)
-
-let apply_subst_reducing subst meta_to_reduce t =
- (* andrea: che senso ha questo ref ?? *)
- let unwinded = ref subst in
- let rec um_aux =
- let module C = Cic in
- let module S = CicSubstitution in
- function
- C.Rel _
- | C.Var _ as t -> t
- | C.Meta (i,l) as t ->
- (try
- S.lift_meta l (List.assoc i !unwinded)
- with Not_found ->
- C.Meta (i,l))
- | C.Sort _ as t -> t
- | C.Implicit as t -> t
- | C.Cast (te,ty) -> C.Cast (um_aux te, um_aux ty)
- | C.Prod (n,s,t) -> C.Prod (n, um_aux s, um_aux t)
- | C.Lambda (n,s,t) -> C.Lambda (n, um_aux s, um_aux t)
- | C.LetIn (n,s,t) -> C.LetIn (n, um_aux s, um_aux t)
- | C.Appl (he::tl) ->
- let tl' = List.map um_aux tl in
- let t' =
- match um_aux he with
- C.Appl l -> C.Appl (l@tl')
- | _ as he' -> C.Appl (he'::tl')
- in
- begin
- match meta_to_reduce,he with
- Some (mtr,reductions_no), C.Meta (m,_) when m = mtr ->
- let rec beta_reduce =
- function
- (n,(C.Appl (C.Lambda (_,_,t)::he'::tl'))) when n > 0 ->
- let he'' = CicSubstitution.subst he' t in
- if tl' = [] then
- he''
- else
- beta_reduce (n-1,C.Appl(he''::tl'))
- | (_,t) -> t
- in
- beta_reduce (reductions_no,t')
- | _,_ -> t'
- end
- | C.Appl _ -> assert false
- | C.Const (uri,exp_named_subst) ->
- let exp_named_subst' =
- List.map (function (uri,t) -> (uri,um_aux t)) exp_named_subst
- in
- C.Const (uri,exp_named_subst')
- | C.MutInd (uri,typeno,exp_named_subst) ->
- let exp_named_subst' =
- List.map (function (uri,t) -> (uri,um_aux t)) exp_named_subst
- in
- C.MutInd (uri,typeno,exp_named_subst')
- | C.MutConstruct (uri,typeno,consno,exp_named_subst) ->
- let exp_named_subst' =
- List.map (function (uri,t) -> (uri,um_aux t)) exp_named_subst
- in
- C.MutConstruct (uri,typeno,consno,exp_named_subst')
- | C.MutCase (sp,i,outty,t,pl) ->
- C.MutCase (sp, i, um_aux outty, um_aux t,
- List.map um_aux pl)
- | C.Fix (i, fl) ->
- let len = List.length fl in
- let liftedfl =
- List.map
- (fun (name, i, ty, bo) -> (name, i, um_aux ty, um_aux bo))
- fl
- in
- C.Fix (i, liftedfl)
- | C.CoFix (i, fl) ->
- let len = List.length fl in
- let liftedfl =
- List.map
- (fun (name, ty, bo) -> (name, um_aux ty, um_aux bo))
- fl
- in
- C.CoFix (i, liftedfl)
- in
- um_aux t
-;;
-
-(* UNWIND THE MGU INSIDE THE MGU *)
-let unwind_subst metasenv subst =
- let identity_relocation_list_for_metavariable i =
- let (_,canonical_context,_) =
- List.find (function (m,_,_) -> m=i) metasenv
- in
- let canonical_context_length = List.length canonical_context in
- let rec aux =
- function
- n when n > canonical_context_length -> []
- | n -> (Some (Cic.Rel n))::(aux (n+1))
- in
- aux 1
- in
- List.fold_left
- (fun (unwinded,metasenv) (i,_) ->
- let identity_relocation_list =
- identity_relocation_list_for_metavariable i
- in
- let (_,metasenv',subst') =
- unwind metasenv subst unwinded (Cic.Meta (i,identity_relocation_list))
- in
- subst',metasenv'
- ) ([],metasenv) subst
-;;
-
-let apply_subst subst t =
- (* metasenv will not be used nor modified. So, let's use a dummy empty one *)
- let metasenv = [] in
- let (t',_,_) = unwind metasenv [] subst t in
- t'
-;;
(* A substitution is a (int * Cic.term) list that associates a *)
(* metavariable i with its body. *)
(* metavariables may have been restricted. *)
let fo_unif metasenv context t1 t2 =
let subst_to_unwind,metasenv' = fo_unif_subst [] context metasenv t1 t2 in
- unwind_subst metasenv' subst_to_unwind
+ CicMetaSubst.unwind_subst metasenv' subst_to_unwind
;;
+
+let fo_unif_subst subst context metasenv t1 t2 =
+ let enrich_msg msg =
+ sprintf "Unification error unifying %s of type %s with %s of type %s in context\n%s\nand metasenv\n%s\nbecause %s"
+ (CicPp.ppterm (CicMetaSubst.apply_subst subst t1))
+ (try
+ CicPp.ppterm (type_of_aux' metasenv subst context t1)
+ with _ -> "MALFORMED")
+ (CicPp.ppterm (CicMetaSubst.apply_subst subst t2))
+ (try
+ CicPp.ppterm (type_of_aux' metasenv subst context t2)
+ with _ -> "MALFORMED")
+ (CicMetaSubst.ppcontext subst context)
+ (CicMetaSubst.ppmetasenv subst metasenv) msg
+ in
+ try
+ fo_unif_subst subst context metasenv t1 t2
+ with
+ | AssertFailure msg -> raise (AssertFailure (enrich_msg msg))
+ | UnificationFailure msg -> raise (UnificationFailure (enrich_msg msg))
+;;
+
projects / helm.git / commitdiff