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typecore.ml
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typecore.ml
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(***********************************************************************)
(* *)
(* OCaml *)
(* *)
(* Xavier Leroy, projet Cristal, INRIA Rocquencourt *)
(* *)
(* Copyright 1996 Institut National de Recherche en Informatique et *)
(* en Automatique. All rights reserved. This file is distributed *)
(* under the terms of the Q Public License version 1.0. *)
(* *)
(***********************************************************************)
(* $Id$ *)
(* Typechecking for the core language *)
open Misc
open Asttypes
open Parsetree
open Types
open Typedtree
open Btype
open Ctype
type error =
Polymorphic_label of Longident.t
| Constructor_arity_mismatch of Longident.t * int * int
| Label_mismatch of Longident.t * (type_expr * type_expr) list
| Pattern_type_clash of (type_expr * type_expr) list
| Multiply_bound_variable of string
| Orpat_vars of Ident.t
| Expr_type_clash of (type_expr * type_expr) list
| Apply_non_function of type_expr
| Apply_wrong_label of label * type_expr
| Label_multiply_defined of Longident.t
| Label_missing of Ident.t list
| Label_not_mutable of Longident.t
| Incomplete_format of string
| Bad_conversion of string * int * char
| Undefined_method of type_expr * string
| Undefined_inherited_method of string
| Virtual_class of Longident.t
| Private_type of type_expr
| Private_label of Longident.t * type_expr
| Unbound_instance_variable of string
| Instance_variable_not_mutable of bool * string
| Not_subtype of (type_expr * type_expr) list * (type_expr * type_expr) list
| Outside_class
| Value_multiply_overridden of string
| Coercion_failure of
type_expr * type_expr * (type_expr * type_expr) list * bool
| Too_many_arguments of bool * type_expr
| Abstract_wrong_label of label * type_expr
| Scoping_let_module of string * type_expr
| Masked_instance_variable of Longident.t
| Not_a_variant_type of Longident.t
| Incoherent_label_order
| Less_general of string * (type_expr * type_expr) list
| Modules_not_allowed
| Cannot_infer_signature
| Not_a_packed_module of type_expr
| Recursive_local_constraint of (type_expr * type_expr) list
| Unexpected_existential
exception Error of Location.t * error
(* Forward declaration, to be filled in by Typemod.type_module *)
let type_module =
ref ((fun env md -> assert false) :
Env.t -> Parsetree.module_expr -> Typedtree.module_expr)
(* Forward declaration, to be filled in by Typemod.type_open *)
let type_open =
ref (fun _ -> assert false)
(* Forward declaration, to be filled in by Typemod.type_package *)
let type_package =
ref (fun _ -> assert false)
(* Forward declaration, to be filled in by Typeclass.class_structure *)
let type_object =
ref (fun env s -> assert false :
Env.t -> Location.t -> Parsetree.class_structure ->
Typedtree.class_structure * Types.class_signature * string list)
(*
Saving and outputting type information.
We keep these function names short, because they have to be
called each time we create a record of type [Typedtree.expression]
or [Typedtree.pattern] that will end up in the typed AST.
*)
let re node =
Cmt_format.add_saved_type (Cmt_format.Partial_expression node);
Stypes.record (Stypes.Ti_expr node);
node
;;
let rp node =
Cmt_format.add_saved_type (Cmt_format.Partial_pattern node);
Stypes.record (Stypes.Ti_pat node);
node
;;
let snd3 (_,x,_) = x
let thd4 (_,_, x,_) = x
(* Upper approximation of free identifiers on the parse tree *)
let iter_expression f e =
let rec expr e =
f e;
match e.pexp_desc with
| Pexp_ident _
| Pexp_assertfalse
| Pexp_new _
| Pexp_constant _ -> ()
| Pexp_function (_, eo, pel) ->
may expr eo; List.iter (fun (_, e) -> expr e) pel
| Pexp_apply (e, lel) -> expr e; List.iter (fun (_, e) -> expr e) lel
| Pexp_let (_, pel, e)
| Pexp_match (e, pel)
| Pexp_try (e, pel) -> expr e; List.iter (fun (_, e) -> expr e) pel
| Pexp_array el
| Pexp_tuple el -> List.iter expr el
| Pexp_construct (_, eo, _)
| Pexp_variant (_, eo) -> may expr eo
| Pexp_record (iel, eo) ->
may expr eo; List.iter (fun (_, e) -> expr e) iel
| Pexp_open (_, e)
| Pexp_newtype (_, e)
| Pexp_poly (e, _)
| Pexp_lazy e
| Pexp_assert e
| Pexp_setinstvar (_, e)
| Pexp_send (e, _)
| Pexp_constraint (e, _, _)
| Pexp_field (e, _) -> expr e
| Pexp_when (e1, e2)
| Pexp_while (e1, e2)
| Pexp_sequence (e1, e2)
| Pexp_setfield (e1, _, e2) -> expr e1; expr e2
| Pexp_ifthenelse (e1, e2, eo) -> expr e1; expr e2; may expr eo
| Pexp_for (_, e1, e2, _, e3) -> expr e1; expr e2; expr e3
| Pexp_override sel -> List.iter (fun (_, e) -> expr e) sel
| Pexp_letmodule (_, me, e) -> expr e; module_expr me
| Pexp_object { pcstr_fields = fs } -> List.iter class_field fs
| Pexp_pack me -> module_expr me
and module_expr me =
match me.pmod_desc with
| Pmod_ident _ -> ()
| Pmod_structure str -> List.iter structure_item str
| Pmod_constraint (me, _)
| Pmod_functor (_, _, me) -> module_expr me
| Pmod_apply (me1, me2) -> module_expr me1; module_expr me2
| Pmod_unpack e -> expr e
and structure_item str =
match str.pstr_desc with
| Pstr_eval e -> expr e
| Pstr_value (_, pel) -> List.iter (fun (_, e) -> expr e) pel
| Pstr_primitive _
| Pstr_type _
| Pstr_exception _
| Pstr_modtype _
| Pstr_open _
| Pstr_class_type _
| Pstr_exn_rebind _ -> ()
| Pstr_include me
| Pstr_module (_, me) -> module_expr me
| Pstr_recmodule l -> List.iter (fun (_, _, me) -> module_expr me) l
| Pstr_class cdl -> List.iter (fun c -> class_expr c.pci_expr) cdl
and class_expr ce =
match ce.pcl_desc with
| Pcl_constr _ -> ()
| Pcl_structure { pcstr_fields = fs } -> List.iter class_field fs
| Pcl_fun (_, eo, _, ce) -> may expr eo; class_expr ce
| Pcl_apply (ce, lel) ->
class_expr ce; List.iter (fun (_, e) -> expr e) lel
| Pcl_let (_, pel, ce) ->
List.iter (fun (_, e) -> expr e) pel; class_expr ce
| Pcl_constraint (ce, _) -> class_expr ce
and class_field cf =
match cf.pcf_desc with
| Pcf_inher (_, ce, _) -> class_expr ce
| Pcf_valvirt _ | Pcf_virt _ | Pcf_constr _ -> ()
| Pcf_val (_,_,_,e) | Pcf_meth (_,_,_,e) -> expr e
| Pcf_init e -> expr e
in
expr e
let all_idents el =
let idents = Hashtbl.create 8 in
let f = function
| {pexp_desc=Pexp_ident { txt = Longident.Lident id; _ }; _} ->
Hashtbl.replace idents id ()
| _ -> ()
in
List.iter (iter_expression f) el;
Hashtbl.fold (fun x () rest -> x :: rest) idents []
(* Typing of constants *)
let type_constant = function
Const_int _ -> instance_def Predef.type_int
| Const_char _ -> instance_def Predef.type_char
| Const_string _ -> instance_def Predef.type_string
| Const_float _ -> instance_def Predef.type_float
| Const_int32 _ -> instance_def Predef.type_int32
| Const_int64 _ -> instance_def Predef.type_int64
| Const_nativeint _ -> instance_def Predef.type_nativeint
(* Specific version of type_option, using newty rather than newgenty *)
let type_option ty =
newty (Tconstr(Predef.path_option,[ty], ref Mnil))
let mkexp exp_desc exp_type exp_loc exp_env =
{ exp_desc; exp_type; exp_loc; exp_env; exp_extra = [] }
let option_none ty loc =
let lid = Longident.Lident "None" in
let (path, cnone) = Env.lookup_constructor lid Env.initial in
mkexp (Texp_construct( path, mknoloc lid, cnone, [], false))
ty loc Env.initial
let option_some texp =
let lid = Longident.Lident "Some" in
let (path, csome) = Env.lookup_constructor lid Env.initial in
mkexp ( Texp_construct(path, mknoloc lid , csome, [texp],false) )
(type_option texp.exp_type) texp.exp_loc texp.exp_env
let extract_option_type env ty =
match expand_head env ty with {desc = Tconstr(path, [ty], _)}
when Path.same path Predef.path_option -> ty
| _ -> assert false
let rec extract_label_names sexp env ty =
let ty = expand_head env ty in
match ty.desc with
| Tconstr (path, _, _) ->
let td = Env.find_type path env in
begin match td.type_kind with
| Type_record (fields, _) ->
List.map (fun (name, _, _) -> name) fields
| Type_abstract when td.type_manifest <> None ->
extract_label_names sexp env (expand_head env ty)
| _ -> assert false
end
| _ ->
assert false
(* Typing of patterns *)
(* unification inside type_pat*)
let unify_pat_types loc env ty ty' =
try
unify env ty ty'
with
Unify trace ->
raise(Error(loc, Pattern_type_clash(trace)))
| Tags(l1,l2) ->
raise(Typetexp.Error(loc, Typetexp.Variant_tags (l1, l2)))
(* unification inside type_exp and type_expect *)
let unify_exp_types loc env ty expected_ty =
(* Format.eprintf "@[%a@ %a@]@." Printtyp.raw_type_expr exp.exp_type
Printtyp.raw_type_expr expected_ty; *)
try
unify env ty expected_ty
with
Unify trace ->
raise(Error(loc, Expr_type_clash(trace)))
| Tags(l1,l2) ->
raise(Typetexp.Error(loc, Typetexp.Variant_tags (l1, l2)))
(* level at which to create the local type declarations *)
let newtype_level = ref None
let get_newtype_level () =
match !newtype_level with
Some y -> y
| None -> assert false
let unify_pat_types_gadt loc env ty ty' =
let newtype_level =
match !newtype_level with
| None -> assert false
| Some x -> x
in
try
unify_gadt ~newtype_level env ty ty'
with
Unify trace ->
raise(Error(loc, Pattern_type_clash(trace)))
| Tags(l1,l2) ->
raise(Typetexp.Error(loc, Typetexp.Variant_tags (l1, l2)))
| Unification_recursive_abbrev trace ->
raise(Error(loc, Recursive_local_constraint trace))
(* Creating new conjunctive types is not allowed when typing patterns *)
let unify_pat env pat expected_ty =
unify_pat_types pat.pat_loc env pat.pat_type expected_ty
(* make all Reither present in open variants *)
let finalize_variant pat =
match pat.pat_desc with
Tpat_variant(tag, opat, r) ->
let row =
match expand_head pat.pat_env pat.pat_type with
{desc = Tvariant row} -> r := row; row_repr row
| _ -> assert false
in
begin match row_field tag row with
| Rabsent -> assert false
| Reither (true, [], _, e) when not row.row_closed ->
set_row_field e (Rpresent None)
| Reither (false, ty::tl, _, e) when not row.row_closed ->
set_row_field e (Rpresent (Some ty));
begin match opat with None -> assert false
| Some pat -> List.iter (unify_pat pat.pat_env pat) (ty::tl)
end
| Reither (c, l, true, e) when not (row_fixed row) ->
set_row_field e (Reither (c, [], false, ref None))
| _ -> ()
end;
(* Force check of well-formedness WHY? *)
(* unify_pat pat.pat_env pat
(newty(Tvariant{row_fields=[]; row_more=newvar(); row_closed=false;
row_bound=(); row_fixed=false; row_name=None})); *)
| _ -> ()
let rec iter_pattern f p =
f p;
iter_pattern_desc (iter_pattern f) p.pat_desc
let has_variants p =
try
iter_pattern (function {pat_desc=Tpat_variant _} -> raise Exit | _ -> ())
p;
false
with Exit ->
true
(* pattern environment *)
let pattern_variables = ref ([] :
(Ident.t * type_expr * string loc * Location.t * bool (* as-variable *)) list)
let pattern_force = ref ([] : (unit -> unit) list)
let pattern_scope = ref (None : Annot.ident option);;
let allow_modules = ref false
let module_variables = ref ([] : (string loc * Location.t) list)
let reset_pattern scope allow =
pattern_variables := [];
pattern_force := [];
pattern_scope := scope;
allow_modules := allow;
module_variables := [];
;;
let enter_variable ?(is_module=false) ?(is_as_variable=false) loc name ty =
if List.exists (fun (id, _, _, _, _) -> Ident.name id = name.txt)
!pattern_variables
then raise(Error(loc, Multiply_bound_variable name.txt));
let id = Ident.create name.txt in
pattern_variables :=
(id, ty, name, loc, is_as_variable) :: !pattern_variables;
if is_module then begin
(* Note: unpack patterns enter a variable of the same name *)
if not !allow_modules then raise (Error (loc, Modules_not_allowed));
module_variables := (name, loc) :: !module_variables
end else
(* moved to genannot *)
may (fun s -> Stypes.record (Stypes.An_ident (name.loc, name.txt, s)))
!pattern_scope;
id
let sort_pattern_variables vs =
List.sort
(fun (x,_,_,_,_) (y,_,_,_,_) ->
Pervasives.compare (Ident.name x) (Ident.name y))
vs
let enter_orpat_variables loc env p1_vs p2_vs =
(* unify_vars operate on sorted lists *)
let p1_vs = sort_pattern_variables p1_vs
and p2_vs = sort_pattern_variables p2_vs in
let rec unify_vars p1_vs p2_vs = match p1_vs, p2_vs with
| (x1,t1,_,l1,a1)::rem1, (x2,t2,_,l2,a2)::rem2 when Ident.equal x1 x2 ->
if x1==x2 then
unify_vars rem1 rem2
else begin
begin try
unify env t1 t2
with
| Unify trace ->
raise(Error(loc, Pattern_type_clash(trace)))
end;
(x2,x1)::unify_vars rem1 rem2
end
| [],[] -> []
| (x,_,_,_,_)::_, [] -> raise (Error (loc, Orpat_vars x))
| [],(x,_,_,_,_)::_ -> raise (Error (loc, Orpat_vars x))
| (x,_,_,_,_)::_, (y,_,_,_,_)::_ ->
let min_var =
if Ident.name x < Ident.name y then x
else y in
raise (Error (loc, Orpat_vars min_var)) in
unify_vars p1_vs p2_vs
let rec build_as_type env p =
match p.pat_desc with
Tpat_alias(p1,_, _) -> build_as_type env p1
| Tpat_tuple pl ->
let tyl = List.map (build_as_type env) pl in
newty (Ttuple tyl)
| Tpat_construct(_, _, cstr, pl,_) ->
let keep = cstr.cstr_private = Private || cstr.cstr_existentials <> [] in
if keep then p.pat_type else
let tyl = List.map (build_as_type env) pl in
let ty_args, ty_res = instance_constructor cstr in
List.iter2 (fun (p,ty) -> unify_pat env {p with pat_type = ty})
(List.combine pl tyl) ty_args;
ty_res
| Tpat_variant(l, p', _) ->
let ty = may_map (build_as_type env) p' in
newty (Tvariant{row_fields=[l, Rpresent ty]; row_more=newvar();
row_bound=(); row_name=None;
row_fixed=false; row_closed=false})
| Tpat_record (lpl,_) ->
let lbl = thd4 (List.hd lpl) in
if lbl.lbl_private = Private then p.pat_type else
let ty = newvar () in
let ppl = List.map (fun (_, _, l, p) -> l.lbl_pos, p) lpl in
let do_label lbl =
let _, ty_arg, ty_res = instance_label false lbl in
unify_pat env {p with pat_type = ty} ty_res;
let refinable =
lbl.lbl_mut = Immutable && List.mem_assoc lbl.lbl_pos ppl &&
match (repr lbl.lbl_arg).desc with Tpoly _ -> false | _ -> true in
if refinable then begin
let arg = List.assoc lbl.lbl_pos ppl in
unify_pat env {arg with pat_type = build_as_type env arg} ty_arg
end else begin
let _, ty_arg', ty_res' = instance_label false lbl in
unify env ty_arg ty_arg';
unify_pat env p ty_res'
end in
Array.iter do_label lbl.lbl_all;
ty
| Tpat_or(p1, p2, row) ->
begin match row with
None ->
let ty1 = build_as_type env p1 and ty2 = build_as_type env p2 in
unify_pat env {p2 with pat_type = ty2} ty1;
ty1
| Some row ->
let row = row_repr row in
newty (Tvariant{row with row_closed=false; row_more=newvar()})
end
| Tpat_any | Tpat_var _ | Tpat_constant _
| Tpat_array _ | Tpat_lazy _ -> p.pat_type
let build_or_pat env loc lid =
let path, decl = Typetexp.find_type env loc lid
in
let tyl = List.map (fun _ -> newvar()) decl.type_params in
let row0 =
let ty = expand_head env (newty(Tconstr(path, tyl, ref Mnil))) in
match ty.desc with
Tvariant row when static_row row -> row
| _ -> raise(Error(loc, Not_a_variant_type lid))
in
let pats, fields =
List.fold_left
(fun (pats,fields) (l,f) ->
match row_field_repr f with
Rpresent None ->
(l,None) :: pats,
(l, Reither(true,[], true, ref None)) :: fields
| Rpresent (Some ty) ->
(l, Some {pat_desc=Tpat_any; pat_loc=Location.none; pat_env=env;
pat_type=ty; pat_extra=[];})
:: pats,
(l, Reither(false, [ty], true, ref None)) :: fields
| _ -> pats, fields)
([],[]) (row_repr row0).row_fields in
let row =
{ row_fields = List.rev fields; row_more = newvar(); row_bound = ();
row_closed = false; row_fixed = false; row_name = Some (path, tyl) }
in
let ty = newty (Tvariant row) in
let gloc = {loc with Location.loc_ghost=true} in
let row' = ref {row with row_more=newvar()} in
let pats =
List.map (fun (l,p) -> {pat_desc=Tpat_variant(l,p,row'); pat_loc=gloc;
pat_env=env; pat_type=ty; pat_extra=[];})
pats
in
match pats with
[] -> raise(Error(loc, Not_a_variant_type lid))
| pat :: pats ->
let r =
List.fold_left
(fun pat pat0 -> {pat_desc=Tpat_or(pat0,pat,Some row0); pat_extra=[];
pat_loc=gloc; pat_env=env; pat_type=ty})
pat pats in
(path, rp { r with pat_loc = loc },ty)
(* Records *)
let rec find_record_qual = function
| [] -> None
| ({ txt = Longident.Ldot (modname, _) }, _) :: _ -> Some modname
| _ :: rest -> find_record_qual rest
let type_label_a_list ?labels env type_lbl_a lid_a_list =
let record_qual = find_record_qual lid_a_list in
let lbl_a_list =
List.map
(fun (lid, a) ->
let path, label =
match lid.txt, labels, record_qual with
Longident.Lident s, Some labels, _ when Hashtbl.mem labels s ->
(Hashtbl.find labels s : Path.t * Types.label_description)
| Longident.Lident s, _, Some modname ->
Typetexp.find_label env lid.loc (Longident.Ldot (modname, s))
| _ ->
Typetexp.find_label env lid.loc lid.txt
in (path, lid, label, a)
) lid_a_list in
(* Invariant: records are sorted in the typed tree *)
let lbl_a_list =
List.sort
(fun ( _, _, lbl1,_) ( _,_, lbl2,_) -> compare lbl1.lbl_pos lbl2.lbl_pos)
lbl_a_list
in
List.map type_lbl_a lbl_a_list
;;
let lid_of_label label =
match repr label.lbl_res with
| {desc = Tconstr(Path.Pdot(mpath,_,_),_,_)} ->
Longident.Ldot(lid_of_path mpath, label.lbl_name)
| _ -> Longident.Lident label.lbl_name
(* Checks over the labels mentioned in a record pattern:
no duplicate definitions (error); properly closed (warning) *)
let check_recordpat_labels loc lbl_pat_list closed =
match lbl_pat_list with
| [] -> () (* should not happen *)
| (_, _, label1, _) :: _ ->
let all = label1.lbl_all in
let defined = Array.make (Array.length all) false in
let check_defined (_, _, label, _) =
if defined.(label.lbl_pos)
then raise(Error(loc, Label_multiply_defined
(Longident.Lident label.lbl_name)))
else defined.(label.lbl_pos) <- true in
List.iter check_defined lbl_pat_list;
if closed = Closed
&& Warnings.is_active (Warnings.Non_closed_record_pattern "")
then begin
let undefined = ref [] in
for i = 0 to Array.length all - 1 do
if not defined.(i) then undefined := all.(i).lbl_name :: !undefined
done;
if !undefined <> [] then begin
let u = String.concat ", " (List.rev !undefined) in
Location.prerr_warning loc (Warnings.Non_closed_record_pattern u)
end
end
(* unification of a type with a tconstr with
freshly created arguments *)
let unify_head_only loc env ty constr =
let (_, ty_res) = instance_constructor constr in
match (repr ty_res).desc with
| Tconstr(p,args,m) ->
ty_res.desc <- Tconstr(p,List.map (fun _ -> newvar ()) args,m);
enforce_constraints env ty_res;
unify_pat_types loc env ty ty_res
| _ -> assert false
(* Typing of patterns *)
(* type_pat does not generate local constraints inside or patterns *)
type type_pat_mode =
| Normal
| Inside_or
(* type_pat propagates the expected type as well as maps for
constructors and labels.
Unification may update the typing environment. *)
let rec type_pat ~constrs ~labels ~no_existentials ~mode ~env sp expected_ty =
let type_pat ?(mode=mode) ?(env=env) =
type_pat ~constrs ~labels ~no_existentials ~mode ~env in
let loc = sp.ppat_loc in
match sp.ppat_desc with
Ppat_any ->
rp {
pat_desc = Tpat_any;
pat_loc = loc; pat_extra=[];
pat_type = expected_ty;
pat_env = !env }
| Ppat_var name ->
let id = enter_variable loc name expected_ty in
rp {
pat_desc = Tpat_var (id, name);
pat_loc = loc; pat_extra=[];
pat_type = expected_ty;
pat_env = !env }
| Ppat_unpack name ->
let id = enter_variable loc name expected_ty ~is_module:true in
rp {
pat_desc = Tpat_var (id, name);
pat_loc = sp.ppat_loc;
pat_extra=[Tpat_unpack, loc];
pat_type = expected_ty;
pat_env = !env }
| Ppat_constraint({ppat_desc=Ppat_var name; ppat_loc=lloc},
({ptyp_desc=Ptyp_poly _} as sty)) ->
(* explicitly polymorphic type *)
let cty, force = Typetexp.transl_simple_type_delayed !env sty in
let ty = cty.ctyp_type in
unify_pat_types lloc !env ty expected_ty;
pattern_force := force :: !pattern_force;
begin match ty.desc with
| Tpoly (body, tyl) ->
begin_def ();
let _, ty' = instance_poly ~keep_names:true false tyl body in
end_def ();
generalize ty';
let id = enter_variable lloc name ty' in
rp {
pat_desc = Tpat_var (id, name);
pat_loc = lloc;
pat_extra = [Tpat_constraint cty, loc];
pat_type = ty;
pat_env = !env
}
| _ -> assert false
end
| Ppat_alias(sq, name) ->
let q = type_pat sq expected_ty in
begin_def ();
let ty_var = build_as_type !env q in
end_def ();
generalize ty_var;
let id = enter_variable ~is_as_variable:true loc name ty_var in
rp {
pat_desc = Tpat_alias(q, id, name);
pat_loc = loc; pat_extra=[];
pat_type = q.pat_type;
pat_env = !env }
| Ppat_constant cst ->
unify_pat_types loc !env (type_constant cst) expected_ty;
rp {
pat_desc = Tpat_constant cst;
pat_loc = loc; pat_extra=[];
pat_type = expected_ty;
pat_env = !env }
| Ppat_tuple spl ->
let spl_ann = List.map (fun p -> (p,newvar ())) spl in
let ty = newty (Ttuple(List.map snd spl_ann)) in
unify_pat_types loc !env ty expected_ty;
let pl = List.map (fun (p,t) -> type_pat p t) spl_ann in
rp {
pat_desc = Tpat_tuple pl;
pat_loc = loc; pat_extra=[];
pat_type = expected_ty;
pat_env = !env }
| Ppat_construct(lid, sarg, explicit_arity) ->
let (constr_path, constr) =
match lid.txt, constrs with
Longident.Lident s, Some constrs when Hashtbl.mem constrs s ->
Hashtbl.find constrs s
| _ -> Typetexp.find_constructor !env loc lid.txt
in
Env.mark_constructor Env.Pattern !env (Longident.last lid.txt) constr;
if no_existentials && constr.cstr_existentials <> [] then
raise (Error (loc, Unexpected_existential));
(* if constructor is gadt, we must verify that the expected type has the
correct head *)
if constr.cstr_generalized then
unify_head_only loc !env expected_ty constr;
let sargs =
match sarg with
None -> []
| Some {ppat_desc = Ppat_tuple spl} when explicit_arity -> spl
| Some {ppat_desc = Ppat_tuple spl} when constr.cstr_arity > 1 -> spl
| Some({ppat_desc = Ppat_any} as sp) when constr.cstr_arity <> 1 ->
if constr.cstr_arity = 0 then
Location.prerr_warning sp.ppat_loc
Warnings.Wildcard_arg_to_constant_constr;
replicate_list sp constr.cstr_arity
| Some sp -> [sp] in
if List.length sargs <> constr.cstr_arity then
raise(Error(loc, Constructor_arity_mismatch(lid.txt,
constr.cstr_arity, List.length sargs)));
let (ty_args, ty_res) =
instance_constructor ~in_pattern:(env, get_newtype_level ()) constr
in
if constr.cstr_generalized && mode = Normal then
unify_pat_types_gadt loc env ty_res expected_ty
else
unify_pat_types loc !env ty_res expected_ty;
let args = List.map2 (fun p t -> type_pat p t) sargs ty_args in
rp {
pat_desc=Tpat_construct(constr_path, lid, constr, args,explicit_arity);
pat_loc = loc; pat_extra=[];
pat_type = expected_ty;
pat_env = !env }
| Ppat_variant(l, sarg) ->
let arg = may_map (fun p -> type_pat p (newvar())) sarg in
let arg_type = match arg with None -> [] | Some arg -> [arg.pat_type] in
let row = { row_fields =
[l, Reither(arg = None, arg_type, true, ref None)];
row_bound = ();
row_closed = false;
row_more = newvar ();
row_fixed = false;
row_name = None } in
unify_pat_types loc !env (newty (Tvariant row)) expected_ty;
rp {
pat_desc = Tpat_variant(l, arg, ref {row with row_more = newvar()});
pat_loc = loc; pat_extra=[];
pat_type = expected_ty;
pat_env = !env }
| Ppat_record(lid_sp_list, closed) ->
let type_label_pat (label_path, label_lid, label, sarg) =
begin_def ();
let (vars, ty_arg, ty_res) = instance_label false label in
if vars = [] then end_def ();
begin try
unify_pat_types loc !env ty_res expected_ty
with Unify trace ->
raise(Error(loc, Label_mismatch(lid_of_label label, trace)))
end;
let arg = type_pat sarg ty_arg in
if vars <> [] then begin
end_def ();
generalize ty_arg;
List.iter generalize vars;
let instantiated tv =
let tv = expand_head !env tv in
not (is_Tvar tv) || tv.level <> generic_level in
if List.exists instantiated vars then
raise (Error(loc, Polymorphic_label (lid_of_label label)))
end;
(label_path, label_lid, label, arg)
in
let lbl_pat_list =
type_label_a_list ?labels !env type_label_pat lid_sp_list in
check_recordpat_labels loc lbl_pat_list closed;
rp {
pat_desc = Tpat_record (lbl_pat_list, closed);
pat_loc = loc; pat_extra=[];
pat_type = expected_ty;
pat_env = !env }
| Ppat_array spl ->
let ty_elt = newvar() in
unify_pat_types
loc !env (instance_def (Predef.type_array ty_elt)) expected_ty;
let spl_ann = List.map (fun p -> (p,newvar())) spl in
let pl = List.map (fun (p,t) -> type_pat p ty_elt) spl_ann in
rp {
pat_desc = Tpat_array pl;
pat_loc = loc; pat_extra=[];
pat_type = expected_ty;
pat_env = !env }
| Ppat_or(sp1, sp2) ->
let initial_pattern_variables = !pattern_variables in
let p1 = type_pat ~mode:Inside_or sp1 expected_ty in
let p1_variables = !pattern_variables in
pattern_variables := initial_pattern_variables;
let p2 = type_pat ~mode:Inside_or sp2 expected_ty in
let p2_variables = !pattern_variables in
let alpha_env =
enter_orpat_variables loc !env p1_variables p2_variables in
pattern_variables := p1_variables;
rp {
pat_desc = Tpat_or(p1, alpha_pat alpha_env p2, None);
pat_loc = loc; pat_extra=[];
pat_type = expected_ty;
pat_env = !env }
| Ppat_lazy sp1 ->
let nv = newvar () in
unify_pat_types loc !env (instance_def (Predef.type_lazy_t nv))
expected_ty;
let p1 = type_pat sp1 nv in
rp {
pat_desc = Tpat_lazy p1;
pat_loc = loc; pat_extra=[];
pat_type = expected_ty;
pat_env = !env }
| Ppat_constraint(sp, sty) ->
(* Separate when not already separated by !principal *)
let separate = true in
if separate then begin_def();
let cty, force = Typetexp.transl_simple_type_delayed !env sty in
let ty = cty.ctyp_type in
let ty, expected_ty' =
if separate then begin
end_def();
generalize_structure ty;
instance !env ty, instance !env ty
end else ty, ty
in
unify_pat_types loc !env ty expected_ty;
let p = type_pat sp expected_ty' in
(*Format.printf "%a@.%a@."
Printtyp.raw_type_expr ty
Printtyp.raw_type_expr p.pat_type;*)
pattern_force := force :: !pattern_force;
if separate then
match p.pat_desc with
Tpat_var (id,s) ->
{p with pat_type = ty;
pat_desc = Tpat_alias ({p with pat_desc = Tpat_any}, id,s);
pat_extra = [Tpat_constraint cty, loc];
}
| _ -> {p with pat_type = ty;
pat_extra = (Tpat_constraint cty,loc) :: p.pat_extra}
else p
| Ppat_type lid ->
let (path, p,ty) = build_or_pat !env loc lid.txt in
unify_pat_types loc !env ty expected_ty;
{ p with pat_extra = (Tpat_type (path, lid), loc) :: p.pat_extra }
let type_pat ?(allow_existentials=false) ?constrs ?labels
?(lev=get_current_level()) env sp expected_ty =
newtype_level := Some lev;
try
let r =
type_pat ~no_existentials:(not allow_existentials) ~constrs ~labels
~mode:Normal ~env sp expected_ty in
iter_pattern (fun p -> p.pat_env <- !env) r;
newtype_level := None;
r
with e ->
newtype_level := None;
raise e
(* this function is passed to Partial.parmatch
to type check gadt nonexhaustiveness *)
let partial_pred ~lev env expected_ty constrs labels p =
let snap = snapshot () in
try
reset_pattern None true;
let typed_p =
type_pat ~allow_existentials:true ~lev
~constrs ~labels (ref env) p expected_ty
in
backtrack snap;
(* types are invalidated but we don't need them here *)
Some typed_p
with _ ->
backtrack snap;
None
let rec iter3 f lst1 lst2 lst3 =
match lst1,lst2,lst3 with
| x1::xs1,x2::xs2,x3::xs3 ->
f x1 x2 x3;
iter3 f xs1 xs2 xs3
| [],[],[] ->
()
| _ ->
assert false
let add_pattern_variables ?check ?check_as env =
let pv = get_ref pattern_variables in
(List.fold_right
(fun (id, ty, name, loc, as_var) env ->
let check = if as_var then check_as else check in
let e1 = Env.add_value ?check id
{val_type = ty; val_kind = Val_reg; Types.val_loc = loc} env in
Env.add_annot id (Annot.Iref_internal loc) e1)
pv env,
get_ref module_variables)
let type_pattern ~lev env spat scope expected_ty =
reset_pattern scope true;
let new_env = ref env in
let pat = type_pat ~allow_existentials:true ~lev new_env spat expected_ty in
let new_env, unpacks =
add_pattern_variables !new_env
~check:(fun s -> Warnings.Unused_var_strict s)
~check_as:(fun s -> Warnings.Unused_var s) in
(pat, new_env, get_ref pattern_force, unpacks)
let type_pattern_list env spatl scope expected_tys allow =
reset_pattern scope allow;
let new_env = ref env in
let patl = List.map2 (type_pat new_env) spatl expected_tys in
let new_env, unpacks = add_pattern_variables !new_env in
(patl, new_env, get_ref pattern_force, unpacks)
let type_class_arg_pattern cl_num val_env met_env l spat =
reset_pattern None false;
let nv = newvar () in
let pat = type_pat (ref val_env) spat nv in
if has_variants pat then begin
Parmatch.pressure_variants val_env [pat];
iter_pattern finalize_variant pat
end;
List.iter (fun f -> f()) (get_ref pattern_force);
if is_optional l then unify_pat val_env pat (type_option (newvar ()));
let (pv, met_env) =
List.fold_right
(fun (id, ty, name, loc, as_var) (pv, env) ->
let check s =
if as_var then Warnings.Unused_var s
else Warnings.Unused_var_strict s in
let id' = Ident.create (Ident.name id) in
((id', name, id, ty)::pv,
Env.add_value id' {val_type = ty;
val_kind = Val_ivar (Immutable, cl_num);
Types.val_loc = loc;
} ~check
env))
!pattern_variables ([], met_env)
in
let val_env, _ = add_pattern_variables val_env in
(pat, pv, val_env, met_env)
let mkpat d = { ppat_desc = d; ppat_loc = Location.none }
let type_self_pattern cl_num privty val_env met_env par_env spat =
let spat =
mkpat (Ppat_alias (mkpat(Ppat_alias (spat, mknoloc "selfpat-*")),
mknoloc ("selfpat-" ^ cl_num)))
in
reset_pattern None false;
let nv = newvar() in
let pat = type_pat (ref val_env) spat nv in
List.iter (fun f -> f()) (get_ref pattern_force);
let meths = ref Meths.empty in
let vars = ref Vars.empty in
let pv = !pattern_variables in
pattern_variables := [];
let (val_env, met_env, par_env) =
List.fold_right
(fun (id, ty, name, loc, as_var) (val_env, met_env, par_env) ->
(Env.add_value id {val_type = ty;
val_kind = Val_unbound;
Types.val_loc = loc;
} val_env,
Env.add_value id {val_type = ty;
val_kind = Val_self (meths, vars, cl_num, privty);
Types.val_loc = loc;
}
~check:(fun s -> if as_var then Warnings.Unused_var s
else Warnings.Unused_var_strict s)
met_env,
Env.add_value id {val_type = ty; val_kind = Val_unbound;
Types.val_loc = loc;
} par_env))
pv (val_env, met_env, par_env)
in
(pat, meths, vars, val_env, met_env, par_env)
let delayed_checks = ref []
let reset_delayed_checks () = delayed_checks := []
let add_delayed_check f = delayed_checks := f :: !delayed_checks
let force_delayed_checks () =
(* checks may change type levels *)
let snap = Btype.snapshot () in
List.iter (fun f -> f ()) (List.rev !delayed_checks);
reset_delayed_checks ();
Btype.backtrack snap
let fst3 (x, _, _) = x
let snd3 (_, x, _) = x
let rec final_subexpression sexp =
match sexp.pexp_desc with
Pexp_let (_, _, e)
| Pexp_sequence (_, e)
| Pexp_try (e, _)
| Pexp_ifthenelse (_, e, _)
| Pexp_match (_, (_, e) :: _)
-> final_subexpression e
| _ -> sexp