[r2003-03-23 21:09:48 by cvscast] Empty log message

Original author: cvscast
Date: 2003-03-23 21:09:49+00:00

driver/cduce.ml

@@ -4,7 +4,6 @@ open Ident
 let quiet = ref false
 
 let typing_env = State.ref "Cduce.typing_env" Typer.Env.empty
-let glb_env = State.ref "Cduce.glb_env" Typer.TypeEnv.empty
 let eval_env = Eval.global_env
 
 let print_norm ppf d = 
@@ -15,9 +14,9 @@ let print_value ppf v =
   Location.protect ppf (fun ppf -> Value.print ppf v)
 
 let dump_env ppf =
-  Format.fprintf ppf "Global types:";
-  Typer.TypeEnv.iter (fun x _ -> Format.fprintf ppf " %s" x) !glb_env;
-  Format.fprintf ppf ".@\n";
+(*  Format.fprintf ppf "Global types:";
+  List.iter (fun x _ -> Format.fprintf ppf " %s" x) (Typer.global_types ()); 
+  Format.fprintf ppf ".@\n"; *)
   Eval.Env.iter 
     (fun x v ->
        let t = Typer.Env.find x !typing_env in
@@ -83,23 +82,23 @@ let rec print_exn ppf = function
 let debug ppf = function
   | `Subtype (t1,t2) ->
       Format.fprintf ppf "[DEBUG:subtype]@\n";
-      let t1 = Types.descr (Typer.typ !glb_env t1)
-      and t2 = Types.descr (Typer.typ !glb_env t2) in
+      let t1 = Types.descr (Typer.typ t1)
+      and t2 = Types.descr (Typer.typ t2) in
       Format.fprintf ppf "%a <= %a : %b@\n" print_norm t1 print_norm t2
 	(Types.subtype t1 t2)
   | `Filter (t,p) -> 
       Format.fprintf ppf "[DEBUG:filter]@\n";
-      let t = Typer.typ !glb_env t
-      and p = Typer.pat !glb_env p in
+      let t = Typer.typ t
+      and p = Typer.pat p in
       let f = Patterns.filter (Types.descr t) p in
       List.iter (fun (x,t) ->
 		   Format.fprintf ppf " %s:%a@\n" (Id.value x)
 		     print_norm (Types.descr t)) f
   | `Compile2 (t,pl) -> 
       Format.fprintf ppf "[DEBUG:compile2]@\n";
-(*      let t = Types.descr (Typer.typ !glb_env t) in
+(*      let t = Types.descr (Typer.typ t) in
       let pl = List.map (fun p -> 
-			   let p = Typer.pat !glb_env p in
+			   let p = Typer.pat p in
 			   let a = Types.descr (Patterns.accept p) in
 			   (Some p, Types.cap a t)) pl in
       let d = Patterns.Compiler.make_dispatcher t pl in
@@ -108,13 +107,13 @@ let debug ppf = function
 
   | `Accept p ->
       Format.fprintf ppf "[DEBUG:accept]@\n";
-      let p = Typer.pat !glb_env p in
+      let p = Typer.pat p in
       let t = Patterns.accept p in
       Format.fprintf ppf " %a@\n" Types.Print.print t
   | `Compile (t,pl) ->
       Format.fprintf ppf "[DEBUG:compile]@\n";
-      let t = Typer.typ !glb_env t
-      and pl = List.map (Typer.pat !glb_env) pl in
+      let t = Typer.typ t
+      and pl = List.map Typer.pat pl in
       Patterns.Compile.debug_compile ppf t pl
   | `Normal_record p -> assert false
 
@@ -123,7 +122,7 @@ let debug ppf = function
 let mk_builtin () =
   let bi = List.map (fun (n,t) -> [n, mknoloc (Ast.Internal t)]) 
 	     Builtin.types in
-  glb_env := List.fold_left Typer.register_global_types !glb_env bi
+  List.iter Typer.register_global_types bi
 
 let () = mk_builtin ()
 
@@ -153,7 +152,7 @@ let run ppf ppf_err input =
   let phrase ph = 
     match ph.descr with
       | Ast.EvalStatement e ->
-	  let (fv,e) = Typer.expr !glb_env e in
+	  let (fv,e) = Typer.expr e in
 	  let t = Typer.type_check !typing_env e Types.any true in
 	  Location.dump_loc ppf e.Typed.exp_loc;
 	  if not !quiet then
@@ -163,7 +162,7 @@ let run ppf ppf_err input =
 	    Format.fprintf ppf "=> @[%a@]@\n@." print_value v
       | Ast.LetDecl (p,{descr=Ast.Abstraction _}) -> ()
       | Ast.LetDecl (p,e) ->
-	  let decl = Typer.let_decl !glb_env p e in
+	  let decl = Typer.let_decl p e in
 	  type_decl decl;
 	  eval_decl decl
       | Ast.TypeDecl _ -> ()
@@ -172,7 +171,7 @@ let run ppf ppf_err input =
   in
 
   let do_fun_decls decls =
-    let decls = List.map (fun (p,e) -> Typer.let_decl !glb_env p e) decls in
+    let decls = List.map (fun (p,e) -> Typer.let_decl p e) decls in
     insert_type_bindings (Typer.type_rec_funs !typing_env decls);
     List.iter eval_decl decls
   in
@@ -201,7 +200,7 @@ let run ppf ppf_err input =
 	       (typs, (p,e)::funs)
 	   | _ -> accu
 	) ([],[]) p in
-    glb_env := Typer.register_global_types !glb_env type_decls;
+    Typer.register_global_types type_decls;
     phrases [] p;
     true
   with 

driver/cduce.mli

@@ -2,7 +2,6 @@ val quiet: bool ref
 
 val typing_env: Typer.env ref  (* Types of toplevel bindings *)
 val eval_env: Eval.env ref     (* Values of toplevel bindings *)
-val glb_env: Typer.glb ref     (* Global types *)
 
 val print_exn: Format.formatter -> exn -> unit
 

parser/ast.ml

@@ -149,3 +149,10 @@ and hash_regexp = function
   | Star x -> 5 + 17 * (hash_regexp x)
   | WeakStar x -> 6 + 17 * (hash_regexp x)
   | SeqCapture (x,y) -> 7 + 17 * (Id.hash x) + 257 * (hash_regexp y)
+
+module PpatTable = Hashtbl.Make
+  (struct
+     type t = ppat
+     let equal = equal_ppat
+     let hash = hash_ppat
+   end)

typing/typer.ml

 (* TODO:
  - rewrite type-checking of operators to propagate constraint
  - rewrite translation of types and patterns -> hash cons
+     CONTINUE THIS...
+     Problem with same name for recursive binders in different
+     recursive type/patterns definitions because of hash-consing
 *)
 
 
@@ -12,11 +15,10 @@ open Ast
 open Ident
 
 module S = struct type t = string let compare = compare end
+module StringSet = Set.Make(S)
 module TypeEnv = Map.Make(S)
 module Env = Map.Make(Ident.Id)
-(*
-module StringSet = Set.Make(S)
-*)
+
 
 exception NonExhaustive of Types.descr
 exception Constraint of Types.descr * Types.descr * string
@@ -26,55 +28,6 @@ exception UnboundId of string
 
 let raise_loc loc exn = raise (Location (loc,exn))
 
-(* Internal representation as a graph (desugar recursive types and regexp),
-   to compute freevars, etc... *)
-
-type ti = {
-  id : int; 
-  mutable seen : bool;
-  mutable loc' : loc;
-  mutable fv : fv option; 
-  mutable descr': descr;
-  mutable type_node: Types.node option;
-  mutable pat_node: Patterns.node option
-} 
-and descr =
-  | IAlias of string * ti
-  | IType of Types.descr
-  | IOr of ti * ti
-  | IAnd of ti * ti
-  | IDiff of ti * ti
-  | ITimes of ti * ti
-  | IXml of ti * ti
-  | IArrow of ti * ti
-  | IOptional of ti
-  | IRecord of bool * ti label_map
-  | ICapture of id
-  | IConstant of id * Types.const
-    
-
-type glb = ti TypeEnv.t
-
-let mk' =
-  let counter = ref 0 in
-  fun loc ->
-    incr counter;
-    let rec x = { 
-      id = !counter; 
-      seen = false;
-      loc' = loc; 
-      fv = None; 
-      descr' = IAlias ("__dummy__", x);
-      type_node = None; 
-      pat_node = None 
-    } in
-    x
-
-let cons loc d =
-  let x = mk' loc in
-  x.descr' <- d;
-  x
-    
 (* Note:
    Compilation of Regexp is implemented as a ``rewriting'' of
    the parsed syntax, in order to be able to print its result
@@ -183,6 +136,7 @@ module Regexp = struct
     defs := [];
     mk_loc !re_loc (Recurs (n,d))
 
+(*
   module H = Hashtbl.Make(
     struct
       type t = Ast.regexp * Ast.ppat
@@ -204,9 +158,338 @@ module Regexp = struct
 	  let c = compile loc regexp queue in
 	  H.add hash (regexp,queue) c;
 	  c
+*)
 end
 
-let compile_regexp = Regexp.compile noloc
+(*
+type descr = 
+  | IType of Types.descr
+  | IOr of descr * descr
+  | IAnd of descr * descr
+  | IDiff of descr * descr
+  | ITimes of slot * slot
+  | IXml of slot * slot
+  | IArrow of slot * slot
+  | IOptional of slot descr
+  | IRecord of bool * slot label_map
+  | ICapture of id
+  | IConstant of id * Types.const
+and slot = {
+  mutable fv : fv option;
+  mutable hash : int option;
+  mutable rank1: int; mutable rank2: int;
+  mutable gen1 : int; mutable gen2: int;
+  mutable d    : slot descr option
+}
+    
+let descr s = 
+  match s.d with
+    | Some d -> d
+    | None -> assert false
+	
+let gen = ref 0
+let rank = ref 0
+	     
+let rec hash_descr = function
+  | IType x -> Types.hash_descr x
+  | IOr (d1,d2) -> 1 + 17 * (hash_descr d1) + 257 * (hash_descr d2)
+  | IAnd (d1,d2) -> 2 + 17 * (hash_descr d1) + 257 * (hash_descr d2)
+  | IDiff (d1,d2) -> 3 + 17 * (hash_descr d1) + 257 * (hash_descr d2)
+  | IOptional d -> 4 + 17 * (hash_descr d)
+  | ITimes (s1,s2) -> 5 + 17 * (hash_slot s1) + 257 * (hash_slot s2)
+  | IXml (s1,s2) -> 6 + 17 * (hash_slot s1) + 257 * (hash_slot s2)
+  | IArrow (s1,s2) -> 7 + 17 * (hash_slot s1) + 257 * (hash_slot s2)
+  | IRecord (o,r) -> (if o then 8 else 9) + 17 * (LabelMap.hash hash_slot r)
+  | ICapture x -> 10 + 17 * (Id.hash x)
+  | IConstant (x,y) -> 11 + 17 * (Id.hash x) + 257 * (Types.hash_const y)
+and hash_slot s =
+  if s.gen1 = !gen then 13 * s.rank1
+  else (
+    incr rank;
+    s.rank1 <- !rank; s.gen1 <- !gen;
+    hash_descr (descr s)
+  )
+    
+let rec equal_descr d1 d2 = 
+  (d1 == d2) ||
+  match (d1,d2) with
+  | IType x1, IType x2 -> Types.equal_descr x1 x2
+  | IOr (x1,y1), IOr (x2,y2) 
+  | IAnd (x1,y1), IAnd (x2,y2) 
+  | IDiff (x1,y1), IDiff (x2,y2) -> (equal_descr x1 x2) && (equal_descr y1 y2)
+  | IOptional x1, IOptional x2 -> equal_descr x1 x2
+  | ITimes (x1,y1), ITimes (x2,y2) 
+  | IXml (x1,y1), IXml (x2,y2) 
+  | IArrow (x1,y1), IArrow (x2,y2) -> (equal_slot x1 x2) && (equal_slot y1 y2)
+  | IRecord (o1,r1), IRecord (o2,r2) -> (o1 = o2) && (LabelMap.equal equal_slot r1 r2)
+  | ICapture x1, ICapture x2 -> Id.equal x1 x2
+  | IConstant (x1,y1), IConstant (x2,y2) -> (Id.equal x1 x2) && (Types.equal_const y1 y2)
+  | _ -> false
+and equal_slot s1 s2 =
+  ((s1.gen1 = !gen) && (s2.gen2 = !gen) && (s1.rank1 = s2.rank2))
+  ||
+  ((s1.gen1 <> !gen) && (s2.gen2 <> !gen) && (
+     incr rank;
+     s1.rank1 <- !rank; s1.gen1 <- !gen;
+     s2.rank2 <- !rank; s2.gen2 <- !gen;
+     equal_descr (descr s1) (descr s2)
+   ))
+  
+module Arg = struct
+  type t = slot
+      
+  let hash s =
+    match s.hash with
+      | Some h -> h
+      | None ->
+	  incr gen; rank := 0; 
+	  let h = hash_slot s in
+	  s.hash <- Some h;
+	  h
+	    
+  let equal s1 s2 = incr gen; rank := 0; equal_slot s1 s2
+end
+module SlotTable = Hashtbl.Make(Arg)
+  
+let rec fv_slot s =
+  match s.fv with
+    | Some x -> x
+    | None ->
+	if s.gen1 = !gen then IdSet.empty 
+	else (s.gen1 <- !gen; fv_descr (descr s))
+and fv_descr = function
+  | IOr (d1,d2)
+  | IAnd (d1,d2)  
+  | IDiff (d1,d2) -> IdSet.cup (fv_descr d1) (fv_descr d2)
+  | IOptional d -> fv_descr d
+  | ITimes (s1,s2)  
+  | IXml (s1,s2)  
+  | IArrow (s1,s2) -> IdSet.cup (fv_slot s1) (fv_slot s2)
+  | IRecord (o,r) -> List.fold_left IdSet.cup IdSet.empty (LabelMap.map_to_list fv_slot r)
+  | ICapture x | IConstant (x,_) -> IdSet.singleton x
+  | _ -> IdSet.empty
+      
+let compute_fv s =
+  match s.fv with
+    | Some x -> ()
+    | None ->
+	incr gen;
+	let x = fv_slot s in
+	s.fv <- Some x
+	  
+	  
+let counter = ref 0
+let todo = ref []
+let rec flush_fv () =
+  List.iter compute_fv !todo;
+  todo := []
+    
+let mk () =   
+  let s = 
+    { d = None;
+      fv = None;
+      hash = None;
+      rank1 = 0; rank2 = 0;
+      gen1 = 0; gen2 = 0 } in
+  todo := s :: !todo;
+  s
+    
+let compile_hash = Ast.PpatTable.create 65
+let defs = ref []
+let rec compile env { loc = loc; descr = d } = 
+  match (d : Ast.ppat') with
+    | PatVar v -> 
+	let (d,loop) = 
+	  try TypeEnv.find v env
+	  with Not_found -> 
+	    raise_loc_generic loc ("Undefined type variable " ^ v) in
+	if !loop then 
+	  raise_loc_generic loc ("Unguarded recursion on type/pattern variable " ^ v);
+	loop := true;
+	let r = compile env d in
+	loop := false;
+	r
+    | Recurs (t, b) -> compile (compile_many env b) t
+    | Regexp (r,q) -> compile env (Regexp.compile loc r q)
+    | Internal t -> IType t
+    | Or (t1,t2) -> IOr (compile env t1, compile env t2)
+    | And (t1,t2) -> IAnd (compile env t1, compile env t2)
+    | Diff (t1,t2) -> IDiff (compile env t1, compile env t2)
+    | Prod (t1,t2) -> ITimes (compile_slot env t1, compile_slot env t2)
+    | XmlT (t1,t2) -> IXml (compile_slot env t1, compile_slot env t2)
+    | Arrow (t1,t2) -> IArrow (compile_slot env t1, compile_slot env t2)
+    | Optional t -> IOptional (compile env t)
+    | Record (o,r) ->  IRecord (o, LabelMap.map (compile_slot env) r)
+    | Constant (x,v) -> IConstant (x,v)
+    | Capture x -> ICapture x
+and compile_slot env ({ loc = loc; descr = d } as p) =
+  try Ast.PpatTable.find compile_hash p
+  with Not_found ->
+    let s = mk () in
+    defs := (s,p,env) :: !defs;
+    Ast.PpatTable.add compile_hash p s;
+    s
+      
+and compile_many env b = 
+  List.fold_left (fun env (v,p) -> TypeEnv.add v (p,ref false) env) env b
+    
+let rec flush_defs () = 
+  match !defs with
+    | [] -> ()
+    | (s,p,env)::t -> defs := t; s.d <- Some (compile env p); flush_defs ()
+	
+let typ_nodes = SlotTable.create 67
+let pat_nodes = SlotTable.create 67
+		  
+let rec typ = function
+  | IType t -> t
+  | IOr (s1,s2) -> Types.cup (typ s1) (typ s2)
+  | IAnd (s1,s2) ->  Types.cap (typ s1) (typ s2)
+  | IDiff (s1,s2) -> Types.diff (typ s1) (typ s2)
+  | ITimes (s1,s2) -> Types.times (typ_node s1) (typ_node s2)
+  | IXml (s1,s2) -> Types.xml (typ_node s1) (typ_node s2)
+  | IArrow (s1,s2) -> Types.arrow (typ_node s1) (typ_node s2)
+  | IOptional s -> Types.Record.or_absent (typ s)
+  | IRecord (o,r) -> Types.record' (o, LabelMap.map typ_node r)
+  | ICapture x | IConstant (x,_) -> assert false
+      
+and typ_node s : Types.node =
+  try SlotTable.find typ_nodes s
+  with Not_found ->
+    let x = Types.make () in
+    SlotTable.add typ_nodes s x;
+    Types.define x (typ (descr s));
+    x
+      
+let rec pat d : Patterns.descr =
+  if IdSet.is_empty (fv_descr d)
+  then Patterns.constr (typ d)
+  else pat_aux d
+    
+    
+and pat_aux = function
+  | IOr (s1,s2) -> Patterns.cup (pat s1) (pat s2)
+  | IAnd (s1,s2) -> Patterns.cap (pat s1) (pat s2)
+  | IDiff (s1,s2) when IdSet.is_empty (fv_descr s2) ->
+      let s2 = Types.neg (typ s2) in
+      Patterns.cap (pat s1) (Patterns.constr s2)
+  | IDiff _ ->
+      raise (Patterns.Error "Difference not allowed in patterns")
+  | ITimes (s1,s2) -> Patterns.times (pat_node s1) (pat_node s2)
+  | IXml (s1,s2) -> Patterns.xml (pat_node s1) (pat_node s2)
+  | IOptional _ -> 
+      raise (Patterns.Error "Optional field not allowed in record patterns")
+  | IRecord (o,r) ->
+      let pats = ref [] in
+      let aux l s = 
+	if IdSet.is_empty (fv_slot s) then typ_node s
+	else
+	  ( pats := Patterns.record l (pat_node s) :: !pats;
+	    Types.any_node )
+      in
+      let constr = Types.record' (o,LabelMap.mapi aux r) in
+      List.fold_left Patterns.cap (Patterns.constr constr) !pats
+	(* TODO: can avoid constr when o=true, and all fields have fv *)
+  | ICapture x -> Patterns.capture x
+  | IConstant (x,c) -> Patterns.constant x c
+  | IArrow _ ->
+      raise (Patterns.Error "Arrow not allowed in patterns")
+  | IType _ -> assert false
+      
+and pat_node s : Patterns.node =
+  try SlotTable.find pat_nodes s
+  with Not_found ->
+    let x = Patterns.make (fv_slot s) in
+    SlotTable.add pat_nodes s x;
+    Patterns.define x (pat (descr s));
+    x
+      
+let glb = State.ref "Typer.glb_env" TypeEnv.empty
+	    
+	    
+let register_global_types b =
+  List.iter (fun (v, { loc = loc }) ->
+	       if TypeEnv.mem v !glb
+	       then raise_loc_generic loc ("Multiple definition for type " ^ v)
+	    ) b;
+  glb := compile_many !glb b;
+  let b = List.map (fun (v,p) -> (v,p,compile !glb p)) b in
+  flush_defs ();
+  flush_fv ();
+  List.iter (fun (v,p,s) -> 
+	       if not (IdSet.is_empty (fv_descr s)) then
+		 raise_loc_generic p.loc "Capture variables are not allowed in types";
+	       Types.Print.register_global v (typ s)) b
+    
+    
+let typ p =
+  let s = compile_slot !glb p in
+  flush_defs ();
+  flush_fv ();
+  if IdSet.is_empty (fv_slot s) then typ_node s
+  else raise_loc_generic p.loc "Capture variables are not allowed in types"
+    
+let pat p = 
+  let s = compile_slot !glb p in
+  flush_defs ();
+  flush_fv ();
+  try pat_node s
+  with Patterns.Error e -> raise_loc_generic p.loc e
+    | Location (loc,exn) when loc = noloc -> raise (Location (p.loc, exn))
+	
+	
+*)
+
+(* Internal representation as a graph (desugar recursive types and regexp),
+   to compute freevars, etc... *)
+
+type ti = {
+  id : int; 
+  mutable seen : bool;
+  mutable loc' : loc;
+  mutable fv : fv option; 
+  mutable descr': descr;
+  mutable type_node: Types.node option;
+  mutable pat_node: Patterns.node option
+} 
+and descr =
+  | IAlias of string * ti
+  | IType of Types.descr
+  | IOr of ti * ti
+  | IAnd of ti * ti
+  | IDiff of ti * ti
+  | ITimes of ti * ti
+  | IXml of ti * ti
+  | IArrow of ti * ti
+  | IOptional of ti
+  | IRecord of bool * ti label_map
+  | ICapture of id
+  | IConstant of id * Types.const
+
+
+
+type glb = ti TypeEnv.t
+
+let mk' =
+  let counter = ref 0 in
+  fun loc ->
+    incr counter;
+    let rec x = { 
+      id = !counter; 
+      seen = false;
+      loc' = loc; 
+      fv = None; 
+      descr' = IAlias ("__dummy__", x);
+      type_node = None; 
+      pat_node = None 
+    } in
+    x
+
+let cons loc d =
+  let x = mk' loc in
+  x.descr' <- d;
+  x
+    
 
 
 let rec compile env { loc = loc; descr = d } : ti = 
@@ -376,24 +659,26 @@ let mk_typ e =
   else raise_loc_generic e.loc' "Capture variables are not allowed in types"
     
 
-let typ glb e =
-  mk_typ (compile glb e)
+let glb = State.ref "Typer.glb_env" TypeEnv.empty
+
+let typ e =
+  mk_typ (compile !glb e)
 
-let pat glb e =
-  pat_node (compile glb e)
+let pat e =
+  pat_node (compile !glb e)
 
-let register_global_types glb b =
-  let env' = compile_many glb b in
-  List.fold_left 
-    (fun glb (v,{ loc = loc }) -> 
+let register_global_types b =
+  let env' = compile_many !glb b in
+  List.iter
+    (fun (v,{ loc = loc }) -> 
        let t = TypeEnv.find v env' in
        let d = Types.descr (mk_typ t) in
        (*	       let d = Types.normalize d in*)
        Types.Print.register_global v d;
-       if TypeEnv.mem v glb
+       if TypeEnv.mem v !glb
        then raise_loc_generic loc ("Multiple definition for type " ^ v);
-       TypeEnv.add v t glb
-    ) glb b
+       glb := TypeEnv.add v t !glb
+    ) b
 
 
 
@@ -404,19 +689,19 @@ module Fv = IdSet
 (* IDEA: introduce a node Loc in the AST to override nolocs
    in sub-expressions *)
    
-let rec expr loc' glb { loc = loc; descr = d } = 
+let rec expr loc' { loc = loc; descr = d } = 
   let loc =  if loc = noloc then loc' else loc in
   let (fv,td) = 
     match d with
       | Forget (e,t) ->
-	  let (fv,e) = expr loc glb e and t = typ glb t in
+	  let (fv,e) = expr loc e and t = typ t in
 	  (fv, Typed.Forget (e,t))
       | Var s -> (Fv.singleton s, Typed.Var s)
       | Apply (e1,e2) -> 
-	  let (fv1,e1) = expr loc glb e1 and (fv2,e2) = expr loc glb e2 in
+	  let (fv1,e1) = expr loc e1 and (fv2,e2) = expr loc e2 in
 	  (Fv.cup fv1 fv2, Typed.Apply (e1,e2))
       | Abstraction a ->
-	  let iface = List.map (fun (t1,t2) -> (typ glb t1, typ glb t2)) 
+	  let iface = List.map (fun (t1,t2) -> (typ t1, typ t2)) 
 			a.fun_iface in
 	  let t = List.fold_left 
 		    (fun accu (t1,t2) -> Types.cap accu (Types.arrow t1 t2)) 
@@ -424,7 +709,7 @@ let rec expr loc' glb { loc = loc; descr = d } =
 	  let iface = List.map 
 			(fun (t1,t2) -> (Types.descr t1, Types.descr t2)) 
 			iface in
-	  let (fv0,body) = branches loc glb a.fun_body in
+	  let (fv0,body) = branches loc a.fun_body in
 	  let fv = match a.fun_name with
 	    | None -> fv0
 	    | Some f -> Fv.remove f fv0 in
@@ -439,46 +724,46 @@ let rec expr loc' glb { loc = loc; descr = d } =
 	  )
       | Cst c -> (Fv.empty, Typed.Cst c)
       | Pair (e1,e2) ->
-	  let (fv1,e1) = expr loc glb e1 and (fv2,e2) = expr loc glb e2 in
+	  let (fv1,e1) = expr loc e1 and (fv2,e2) = expr loc e2 in
 	  (Fv.cup fv1 fv2, Typed.Pair (e1,e2))
       | Xml (e1,e2) ->