ocaml/typing/typetexp.ml

914 lines
33 KiB
OCaml

(**************************************************************************)
(* *)
(* 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 GNU Lesser General Public License version 2.1, with the *)
(* special exception on linking described in the file LICENSE. *)
(* *)
(**************************************************************************)
(* typetexp.ml,v 1.34.4.9 2002/01/07 08:39:16 garrigue Exp *)
(* Typechecking of type expressions for the core language *)
open Asttypes
open Misc
open Parsetree
open Typedtree
open Types
open Ctype
exception Already_bound
type error =
Unbound_type_variable of string
| Unbound_type_constructor of Longident.t
| Unbound_type_constructor_2 of Path.t
| Type_arity_mismatch of Longident.t * int * int
| Bound_type_variable of string
| Recursive_type
| Unbound_row_variable of Longident.t
| Type_mismatch of (type_expr * type_expr) list
| Alias_type_mismatch of (type_expr * type_expr) list
| Present_has_conjunction of string
| Present_has_no_type of string
| Constructor_mismatch of type_expr * type_expr
| Not_a_variant of type_expr
| Variant_tags of string * string
| Invalid_variable_name of string
| Cannot_quantify of string * type_expr
| Multiple_constraints_on_type of Longident.t
| Repeated_method_label of string
| Unbound_value of Longident.t
| Unbound_constructor of Longident.t
| Unbound_label of Longident.t
| Unbound_module of Longident.t
| Unbound_class of Longident.t
| Unbound_modtype of Longident.t
| Unbound_cltype of Longident.t
| Ill_typed_functor_application of Longident.t
| Illegal_reference_to_recursive_module
| Access_functor_as_structure of Longident.t
| Apply_structure_as_functor of Longident.t
| Cannot_scrape_alias of Longident.t * Path.t
exception Error of Location.t * Env.t * error
exception Error_forward of Location.error
type variable_context = int * (string, type_expr) Tbl.t
(* Local definitions *)
let instance_list = Ctype.instance_list Env.empty
(* Narrowing unbound identifier errors. *)
let rec narrow_unbound_lid_error : 'a. _ -> _ -> _ -> _ -> 'a =
fun env loc lid make_error ->
let check_module mlid =
try ignore (Env.lookup_module true mlid env) with
| Not_found ->
narrow_unbound_lid_error env loc mlid (fun lid -> Unbound_module lid)
| Env.Recmodule ->
raise (Error (loc, env, Illegal_reference_to_recursive_module))
in
begin match lid with
| Longident.Lident _ -> ()
| Longident.Ldot (mlid, _) ->
check_module mlid;
let md = Env.find_module (Env.lookup_module true mlid env) env in
begin match Env.scrape_alias env md.md_type with
| Mty_functor _ ->
raise (Error (loc, env, Access_functor_as_structure mlid))
| Mty_alias p ->
raise (Error (loc, env, Cannot_scrape_alias(mlid, p)))
| _ -> ()
end
| Longident.Lapply (flid, mlid) ->
check_module flid;
let fmd = Env.find_module (Env.lookup_module true flid env) env in
begin match Env.scrape_alias env fmd.md_type with
| Mty_signature _ ->
raise (Error (loc, env, Apply_structure_as_functor flid))
| Mty_alias p ->
raise (Error (loc, env, Cannot_scrape_alias(flid, p)))
| _ -> ()
end;
let mmd = Env.find_module (Env.lookup_module true mlid env) env in
check_module mlid;
begin match Env.scrape_alias env mmd.md_type with
| Mty_alias p ->
raise (Error (loc, env, Cannot_scrape_alias(mlid, p)))
| _ ->
raise (Error (loc, env, Ill_typed_functor_application lid))
end
end;
raise (Error (loc, env, make_error lid))
let find_component lookup make_error env loc lid =
try
match lid with
| Longident.Ldot (Longident.Lident "*predef*", s) ->
lookup ?loc:(Some loc) (Longident.Lident s) Env.initial_safe_string
| _ ->
lookup ?loc:(Some loc) lid env
with Not_found ->
narrow_unbound_lid_error env loc lid make_error
| Env.Recmodule ->
raise (Error (loc, env, Illegal_reference_to_recursive_module))
let find_type env loc lid =
let (path, decl) as r =
find_component Env.lookup_type (fun lid -> Unbound_type_constructor lid)
env loc lid
in
Builtin_attributes.check_deprecated loc decl.type_attributes (Path.name path);
r
let find_constructor =
find_component Env.lookup_constructor (fun lid -> Unbound_constructor lid)
let find_all_constructors =
find_component Env.lookup_all_constructors
(fun lid -> Unbound_constructor lid)
let find_label =
find_component Env.lookup_label (fun lid -> Unbound_label lid)
let find_all_labels =
find_component Env.lookup_all_labels (fun lid -> Unbound_label lid)
let find_class env loc lid =
let (path, decl) as r =
find_component Env.lookup_class (fun lid -> Unbound_class lid) env loc lid
in
Builtin_attributes.check_deprecated loc decl.cty_attributes (Path.name path);
r
let find_value env loc lid =
Env.check_value_name (Longident.last lid) loc;
let (path, decl) as r =
find_component Env.lookup_value (fun lid -> Unbound_value lid) env loc lid
in
Builtin_attributes.check_deprecated loc decl.val_attributes (Path.name path);
r
let lookup_module ?(load=false) env loc lid =
find_component (fun ?loc lid env -> (Env.lookup_module ~load ?loc lid env))
(fun lid -> Unbound_module lid) env loc lid
let find_module env loc lid =
let path = lookup_module ~load:true env loc lid in
let decl = Env.find_module path env in
(* No need to check for deprecated here, this is done in Env. *)
(path, decl)
let find_modtype env loc lid =
let (path, decl) as r =
find_component Env.lookup_modtype (fun lid -> Unbound_modtype lid)
env loc lid
in
Builtin_attributes.check_deprecated loc decl.mtd_attributes (Path.name path);
r
let find_class_type env loc lid =
let (path, decl) as r =
find_component Env.lookup_cltype (fun lid -> Unbound_cltype lid)
env loc lid
in
Builtin_attributes.check_deprecated loc decl.clty_attributes (Path.name path);
r
let unbound_constructor_error env lid =
narrow_unbound_lid_error env lid.loc lid.txt
(fun lid -> Unbound_constructor lid)
let unbound_label_error env lid =
narrow_unbound_lid_error env lid.loc lid.txt
(fun lid -> Unbound_label lid)
(* Support for first-class modules. *)
let transl_modtype_longident = ref (fun _ -> assert false)
let transl_modtype = ref (fun _ -> assert false)
let create_package_mty fake loc env (p, l) =
let l =
List.sort
(fun (s1, t1) (s2, t2) ->
if s1.txt = s2.txt then
raise (Error (loc, env, Multiple_constraints_on_type s1.txt));
compare s1.txt s2.txt)
l
in
l,
List.fold_left
(fun mty (s, t) ->
let d = {ptype_name = mkloc (Longident.last s.txt) s.loc;
ptype_params = [];
ptype_cstrs = [];
ptype_kind = Ptype_abstract;
ptype_private = Asttypes.Public;
ptype_manifest = if fake then None else Some t;
ptype_attributes = [];
ptype_loc = loc} in
Ast_helper.Mty.mk ~loc
(Pmty_with (mty, [ Pwith_type ({ txt = s.txt; loc }, d) ]))
)
(Ast_helper.Mty.mk ~loc (Pmty_ident p))
l
(* Translation of type expressions *)
let type_variables = ref (Tbl.empty : (string, type_expr) Tbl.t)
let univars = ref ([] : (string * type_expr) list)
let pre_univars = ref ([] : type_expr list)
let used_variables = ref (Tbl.empty : (string, type_expr * Location.t) Tbl.t)
let reset_type_variables () =
reset_global_level ();
Ctype.reset_reified_var_counter ();
type_variables := Tbl.empty
let narrow () =
(increase_global_level (), !type_variables)
let widen (gl, tv) =
restore_global_level gl;
type_variables := tv
let strict_ident c = (c = '_' || c >= 'a' && c <= 'z' || c >= 'A' && c <= 'Z')
let validate_name = function
None -> None
| Some name as s ->
if name <> "" && strict_ident name.[0] then s else None
let new_global_var ?name () =
new_global_var ?name:(validate_name name) ()
let newvar ?name () =
newvar ?name:(validate_name name) ()
let type_variable loc name =
try
Tbl.find name !type_variables
with Not_found ->
raise(Error(loc, Env.empty, Unbound_type_variable ("'" ^ name)))
let transl_type_param env styp =
let loc = styp.ptyp_loc in
match styp.ptyp_desc with
Ptyp_any ->
let ty = new_global_var ~name:"_" () in
{ ctyp_desc = Ttyp_any; ctyp_type = ty; ctyp_env = env;
ctyp_loc = loc; ctyp_attributes = styp.ptyp_attributes; }
| Ptyp_var name ->
let ty =
try
if name <> "" && name.[0] = '_' then
raise (Error (loc, Env.empty, Invalid_variable_name ("'" ^ name)));
ignore (Tbl.find name !type_variables);
raise Already_bound
with Not_found ->
let v = new_global_var ~name () in
type_variables := Tbl.add name v !type_variables;
v
in
{ ctyp_desc = Ttyp_var name; ctyp_type = ty; ctyp_env = env;
ctyp_loc = loc; ctyp_attributes = styp.ptyp_attributes; }
| _ -> assert false
let new_pre_univar ?name () =
let v = newvar ?name () in pre_univars := v :: !pre_univars; v
let rec swap_list = function
x :: y :: l -> y :: x :: swap_list l
| l -> l
type policy = Fixed | Extensible | Univars
let rec transl_type env policy styp =
let loc = styp.ptyp_loc in
let ctyp ctyp_desc ctyp_type =
{ ctyp_desc; ctyp_type; ctyp_env = env;
ctyp_loc = loc; ctyp_attributes = styp.ptyp_attributes }
in
match styp.ptyp_desc with
Ptyp_any ->
let ty =
if policy = Univars then new_pre_univar () else
if policy = Fixed then
raise (Error (styp.ptyp_loc, env, Unbound_type_variable "_"))
else newvar ()
in
ctyp Ttyp_any ty
| Ptyp_var name ->
let ty =
if name <> "" && name.[0] = '_' then
raise (Error (styp.ptyp_loc, env, Invalid_variable_name ("'" ^ name)));
begin try
instance env (List.assoc name !univars)
with Not_found -> try
instance env (fst(Tbl.find name !used_variables))
with Not_found ->
let v =
if policy = Univars then new_pre_univar ~name () else newvar ~name ()
in
used_variables := Tbl.add name (v, styp.ptyp_loc) !used_variables;
v
end
in
ctyp (Ttyp_var name) ty
| Ptyp_arrow(l, st1, st2) ->
let cty1 = transl_type env policy st1 in
let cty2 = transl_type env policy st2 in
let ty1 = cty1.ctyp_type in
let ty1 =
if Btype.is_optional l
then newty (Tconstr(Predef.path_option,[ty1], ref Mnil))
else ty1 in
let ty = newty (Tarrow(l, ty1, cty2.ctyp_type, Cok)) in
ctyp (Ttyp_arrow (l, cty1, cty2)) ty
| Ptyp_tuple stl ->
assert (List.length stl >= 2);
let ctys = List.map (transl_type env policy) stl in
let ty = newty (Ttuple (List.map (fun ctyp -> ctyp.ctyp_type) ctys)) in
ctyp (Ttyp_tuple ctys) ty
| Ptyp_constr(lid, stl) ->
let (path, decl) = find_type env styp.ptyp_loc lid.txt in
let stl =
match stl with
| [ {ptyp_desc=Ptyp_any} as t ] when decl.type_arity > 1 ->
List.map (fun _ -> t) decl.type_params
| _ -> stl
in
if List.length stl <> decl.type_arity then
raise(Error(styp.ptyp_loc, env,
Type_arity_mismatch(lid.txt, decl.type_arity,
List.length stl)));
let args = List.map (transl_type env policy) stl in
let params = instance_list decl.type_params in
let unify_param =
match decl.type_manifest with
None -> unify_var
| Some ty ->
if (repr ty).level = Btype.generic_level then unify_var else unify
in
List.iter2
(fun (sty, cty) ty' ->
try unify_param env ty' cty.ctyp_type with Unify trace ->
raise (Error(sty.ptyp_loc, env, Type_mismatch (swap_list trace))))
(List.combine stl args) params;
let constr =
newconstr path (List.map (fun ctyp -> ctyp.ctyp_type) args) in
begin try
Ctype.enforce_constraints env constr
with Unify trace ->
raise (Error(styp.ptyp_loc, env, Type_mismatch trace))
end;
ctyp (Ttyp_constr (path, lid, args)) constr
| Ptyp_object (fields, o) ->
let fields =
List.map (fun (s, a, t) -> (s, a, transl_poly_type env policy t))
fields
in
let ty = newobj (transl_fields loc env policy [] o fields) in
ctyp (Ttyp_object (fields, o)) ty
| Ptyp_class(lid, stl) ->
let (path, decl, is_variant) =
try
let (path, decl) = Env.lookup_type lid.txt env in
let rec check decl =
match decl.type_manifest with
None -> raise Not_found
| Some ty ->
match (repr ty).desc with
Tvariant row when Btype.static_row row -> ()
| Tconstr (path, _, _) ->
check (Env.find_type path env)
| _ -> raise Not_found
in check decl;
Location.prerr_warning styp.ptyp_loc
(Warnings.Deprecated "old syntax for polymorphic variant type");
(path, decl,true)
with Not_found -> try
let lid2 =
match lid.txt with
Longident.Lident s -> Longident.Lident ("#" ^ s)
| Longident.Ldot(r, s) -> Longident.Ldot (r, "#" ^ s)
| Longident.Lapply(_, _) -> fatal_error "Typetexp.transl_type"
in
let (path, decl) = Env.lookup_type lid2 env in
(path, decl, false)
with Not_found ->
ignore (find_class env styp.ptyp_loc lid.txt); assert false
in
if List.length stl <> decl.type_arity then
raise(Error(styp.ptyp_loc, env,
Type_arity_mismatch(lid.txt, decl.type_arity,
List.length stl)));
let args = List.map (transl_type env policy) stl in
let params = instance_list decl.type_params in
List.iter2
(fun (sty, cty) ty' ->
try unify_var env ty' cty.ctyp_type with Unify trace ->
raise (Error(sty.ptyp_loc, env, Type_mismatch (swap_list trace))))
(List.combine stl args) params;
let ty_args = List.map (fun ctyp -> ctyp.ctyp_type) args in
let ty =
try Ctype.expand_head env (newconstr path ty_args)
with Unify trace ->
raise (Error(styp.ptyp_loc, env, Type_mismatch trace))
in
let ty = match ty.desc with
Tvariant row ->
let row = Btype.row_repr row in
let fields =
List.map
(fun (l,f) -> l,
match Btype.row_field_repr f with
| Rpresent (Some ty) ->
Reither(false, [ty], false, ref None)
| Rpresent None ->
Reither (true, [], false, ref None)
| _ -> f)
row.row_fields
in
let row = { row_closed = true; row_fields = fields;
row_bound = (); row_name = Some (path, ty_args);
row_fixed = false; row_more = newvar () } in
let static = Btype.static_row row in
let row =
if static then { row with row_more = newty Tnil }
else if policy <> Univars then row
else { row with row_more = new_pre_univar () }
in
newty (Tvariant row)
| Tobject (fi, _) ->
let _, tv = flatten_fields fi in
if policy = Univars then pre_univars := tv :: !pre_univars;
ty
| _ ->
assert false
in
ctyp (Ttyp_class (path, lid, args)) ty
| Ptyp_alias(st, alias) ->
let cty =
try
let t =
try List.assoc alias !univars
with Not_found ->
instance env (fst(Tbl.find alias !used_variables))
in
let ty = transl_type env policy st in
begin try unify_var env t ty.ctyp_type with Unify trace ->
let trace = swap_list trace in
raise(Error(styp.ptyp_loc, env, Alias_type_mismatch trace))
end;
ty
with Not_found ->
if !Clflags.principal then begin_def ();
let t = newvar () in
used_variables := Tbl.add alias (t, styp.ptyp_loc) !used_variables;
let ty = transl_type env policy st in
begin try unify_var env t ty.ctyp_type with Unify trace ->
let trace = swap_list trace in
raise(Error(styp.ptyp_loc, env, Alias_type_mismatch trace))
end;
if !Clflags.principal then begin
end_def ();
generalize_structure t;
end;
let t = instance env t in
let px = Btype.proxy t in
begin match px.desc with
| Tvar None -> Btype.log_type px; px.desc <- Tvar (Some alias)
| Tunivar None -> Btype.log_type px; px.desc <- Tunivar (Some alias)
| _ -> ()
end;
{ ty with ctyp_type = t }
in
ctyp (Ttyp_alias (cty, alias)) cty.ctyp_type
| Ptyp_variant(fields, closed, present) ->
let name = ref None in
let mkfield l f =
newty (Tvariant {row_fields=[l,f]; row_more=newvar();
row_bound=(); row_closed=true;
row_fixed=false; row_name=None}) in
let hfields = Hashtbl.create 17 in
let add_typed_field loc l f =
let h = Btype.hash_variant l in
try
let (l',f') = Hashtbl.find hfields h in
(* Check for tag conflicts *)
if l <> l' then raise(Error(styp.ptyp_loc, env, Variant_tags(l, l')));
let ty = mkfield l f and ty' = mkfield l f' in
if equal env false [ty] [ty'] then () else
try unify env ty ty'
with Unify trace ->
raise(Error(loc, env, Constructor_mismatch (ty,ty')))
with Not_found ->
Hashtbl.add hfields h (l,f)
in
let add_field = function
Rtag (l, attrs, c, stl) ->
name := None;
let tl = List.map (transl_type env policy) stl in
let f = match present with
Some present when not (List.mem l present) ->
let ty_tl = List.map (fun cty -> cty.ctyp_type) tl in
Reither(c, ty_tl, false, ref None)
| _ ->
if List.length stl > 1 || c && stl <> [] then
raise(Error(styp.ptyp_loc, env, Present_has_conjunction l));
match tl with [] -> Rpresent None
| st :: _ ->
Rpresent (Some st.ctyp_type)
in
add_typed_field styp.ptyp_loc l f;
Ttag (l,attrs,c,tl)
| Rinherit sty ->
let cty = transl_type env policy sty in
let ty = cty.ctyp_type in
let nm =
match repr cty.ctyp_type with
{desc=Tconstr(p, tl, _)} -> Some(p, tl)
| _ -> None
in
begin try
(* Set name if there are no fields yet *)
Hashtbl.iter (fun _ _ -> raise Exit) hfields;
name := nm
with Exit ->
(* Unset it otherwise *)
name := None
end;
let fl = match expand_head env cty.ctyp_type, nm with
{desc=Tvariant row}, _ when Btype.static_row row ->
let row = Btype.row_repr row in
row.row_fields
| {desc=Tvar _}, Some(p, _) ->
raise(Error(sty.ptyp_loc, env, Unbound_type_constructor_2 p))
| _ ->
raise(Error(sty.ptyp_loc, env, Not_a_variant ty))
in
List.iter
(fun (l, f) ->
let f = match present with
Some present when not (List.mem l present) ->
begin match f with
Rpresent(Some ty) ->
Reither(false, [ty], false, ref None)
| Rpresent None ->
Reither(true, [], false, ref None)
| _ ->
assert false
end
| _ -> f
in
add_typed_field sty.ptyp_loc l f)
fl;
Tinherit cty
in
let tfields = List.map add_field fields in
let fields = Hashtbl.fold (fun _ p l -> p :: l) hfields [] in
begin match present with None -> ()
| Some present ->
List.iter
(fun l -> if not (List.mem_assoc l fields) then
raise(Error(styp.ptyp_loc, env, Present_has_no_type l)))
present
end;
let row =
{ row_fields = List.rev fields; row_more = newvar ();
row_bound = (); row_closed = (closed = Closed);
row_fixed = false; row_name = !name } in
let static = Btype.static_row row in
let row =
if static then { row with row_more = newty Tnil }
else if policy <> Univars then row
else { row with row_more = new_pre_univar () }
in
let ty = newty (Tvariant row) in
ctyp (Ttyp_variant (tfields, closed, present)) ty
| Ptyp_poly(vars, st) ->
begin_def();
let new_univars = List.map (fun name -> name, newvar ~name ()) vars in
let old_univars = !univars in
univars := new_univars @ !univars;
let cty = transl_type env policy st in
let ty = cty.ctyp_type in
univars := old_univars;
end_def();
generalize ty;
let ty_list =
List.fold_left
(fun tyl (name, ty1) ->
let v = Btype.proxy ty1 in
if deep_occur v ty then begin
match v.desc with
Tvar name when v.level = Btype.generic_level ->
v.desc <- Tunivar name;
v :: tyl
| _ ->
raise (Error (styp.ptyp_loc, env, Cannot_quantify (name, v)))
end else tyl)
[] new_univars
in
let ty' = Btype.newgenty (Tpoly(ty, List.rev ty_list)) in
unify_var env (newvar()) ty';
ctyp (Ttyp_poly (vars, cty)) ty'
| Ptyp_package (p, l) ->
let l, mty = create_package_mty true styp.ptyp_loc env (p, l) in
let z = narrow () in
let mty = !transl_modtype env mty in
widen z;
let ptys = List.map (fun (s, pty) ->
s, transl_type env policy pty
) l in
let path = !transl_modtype_longident styp.ptyp_loc env p.txt in
let ty = newty (Tpackage (path,
List.map (fun (s, pty) -> s.txt) l,
List.map (fun (_,cty) -> cty.ctyp_type) ptys))
in
ctyp (Ttyp_package {
pack_path = path;
pack_type = mty.mty_type;
pack_fields = ptys;
pack_txt = p;
}) ty
| Ptyp_extension ext ->
raise (Error_forward (Builtin_attributes.error_of_extension ext))
and transl_poly_type env policy t =
transl_type env policy (Ast_helper.Typ.force_poly t)
and transl_fields loc env policy seen o =
function
[] ->
begin match o, policy with
| Closed, _ -> newty Tnil
| Open, Univars -> new_pre_univar ()
| Open, _ -> newvar ()
end
| (s, _attrs, ty1) :: l ->
if List.mem s seen then raise (Error (loc, env, Repeated_method_label s));
let ty2 = transl_fields loc env policy (s :: seen) o l in
newty (Tfield (s, Fpresent, ty1.ctyp_type, ty2))
(* Make the rows "fixed" in this type, to make universal check easier *)
let rec make_fixed_univars ty =
let ty = repr ty in
if ty.level >= Btype.lowest_level then begin
Btype.mark_type_node ty;
match ty.desc with
| Tvariant row ->
let row = Btype.row_repr row in
if Btype.is_Tunivar (Btype.row_more row) then
ty.desc <- Tvariant
{row with row_fixed=true;
row_fields = List.map
(fun (s,f as p) -> match Btype.row_field_repr f with
Reither (c, tl, m, r) -> s, Reither (c, tl, true, r)
| _ -> p)
row.row_fields};
Btype.iter_row make_fixed_univars row
| _ ->
Btype.iter_type_expr make_fixed_univars ty
end
let make_fixed_univars ty =
make_fixed_univars ty;
Btype.unmark_type ty
let create_package_mty = create_package_mty false
let globalize_used_variables env fixed =
let r = ref [] in
Tbl.iter
(fun name (ty, loc) ->
let v = new_global_var () in
let snap = Btype.snapshot () in
if try unify env v ty; true with _ -> Btype.backtrack snap; false
then try
r := (loc, v, Tbl.find name !type_variables) :: !r
with Not_found ->
if fixed && Btype.is_Tvar (repr ty) then
raise(Error(loc, env, Unbound_type_variable ("'"^name)));
let v2 = new_global_var () in
r := (loc, v, v2) :: !r;
type_variables := Tbl.add name v2 !type_variables)
!used_variables;
used_variables := Tbl.empty;
fun () ->
List.iter
(function (loc, t1, t2) ->
try unify env t1 t2 with Unify trace ->
raise (Error(loc, env, Type_mismatch trace)))
!r
let transl_simple_type env fixed styp =
univars := []; used_variables := Tbl.empty;
let typ = transl_type env (if fixed then Fixed else Extensible) styp in
globalize_used_variables env fixed ();
make_fixed_univars typ.ctyp_type;
typ
let transl_simple_type_univars env styp =
univars := []; used_variables := Tbl.empty; pre_univars := [];
begin_def ();
let typ = transl_type env Univars styp in
(* Only keep already global variables in used_variables *)
let new_variables = !used_variables in
used_variables := Tbl.empty;
Tbl.iter
(fun name p ->
if Tbl.mem name !type_variables then
used_variables := Tbl.add name p !used_variables)
new_variables;
globalize_used_variables env false ();
end_def ();
generalize typ.ctyp_type;
let univs =
List.fold_left
(fun acc v ->
let v = repr v in
match v.desc with
Tvar name when v.level = Btype.generic_level ->
v.desc <- Tunivar name; v :: acc
| _ -> acc)
[] !pre_univars
in
make_fixed_univars typ.ctyp_type;
{ typ with ctyp_type =
instance env (Btype.newgenty (Tpoly (typ.ctyp_type, univs))) }
let transl_simple_type_delayed env styp =
univars := []; used_variables := Tbl.empty;
let typ = transl_type env Extensible styp in
make_fixed_univars typ.ctyp_type;
(typ, globalize_used_variables env false)
let transl_type_scheme env styp =
reset_type_variables();
begin_def();
let typ = transl_simple_type env false styp in
end_def();
generalize typ.ctyp_type;
typ
(* Error report *)
open Format
open Printtyp
let spellcheck ppf fold env lid =
let choices ~path name =
let env = fold (fun x xs -> x::xs) path env [] in
Misc.spellcheck env name in
match lid with
| Longident.Lapply _ -> ()
| Longident.Lident s ->
Misc.did_you_mean ppf (fun () -> choices ~path:None s)
| Longident.Ldot (r, s) ->
Misc.did_you_mean ppf (fun () -> choices ~path:(Some r) s)
let fold_descr fold get_name f = fold (fun descr acc -> f (get_name descr) acc)
let fold_simple fold4 f = fold4 (fun name _path _descr acc -> f name acc)
let fold_values = fold_simple Env.fold_values
let fold_types = fold_simple Env.fold_types
let fold_modules = fold_simple Env.fold_modules
let fold_constructors = fold_descr Env.fold_constructors (fun d -> d.cstr_name)
let fold_labels = fold_descr Env.fold_labels (fun d -> d.lbl_name)
let fold_classs = fold_simple Env.fold_classs
let fold_modtypes = fold_simple Env.fold_modtypes
let fold_cltypes = fold_simple Env.fold_cltypes
let report_error env ppf = function
| Unbound_type_variable name ->
(* we don't use "spellcheck" here: the function that raises this
error seems not to be called anywhere, so it's unclear how it
should be handled *)
fprintf ppf "Unbound type parameter %s@." name
| Unbound_type_constructor lid ->
fprintf ppf "Unbound type constructor %a" longident lid;
spellcheck ppf fold_types env lid;
| Unbound_type_constructor_2 p ->
fprintf ppf "The type constructor@ %a@ is not yet completely defined"
path p
| Type_arity_mismatch(lid, expected, provided) ->
fprintf ppf
"@[The type constructor %a@ expects %i argument(s),@ \
but is here applied to %i argument(s)@]"
longident lid expected provided
| Bound_type_variable name ->
fprintf ppf "Already bound type parameter '%s" name
| Recursive_type ->
fprintf ppf "This type is recursive"
| Unbound_row_variable lid ->
(* we don't use "spellcheck" here: this error is not raised
anywhere so it's unclear how it should be handled *)
fprintf ppf "Unbound row variable in #%a" longident lid
| Type_mismatch trace ->
Printtyp.report_unification_error ppf Env.empty trace
(function ppf ->
fprintf ppf "This type")
(function ppf ->
fprintf ppf "should be an instance of type")
| Alias_type_mismatch trace ->
Printtyp.report_unification_error ppf Env.empty trace
(function ppf ->
fprintf ppf "This alias is bound to type")
(function ppf ->
fprintf ppf "but is used as an instance of type")
| Present_has_conjunction l ->
fprintf ppf "The present constructor %s has a conjunctive type" l
| Present_has_no_type l ->
fprintf ppf "The present constructor %s has no type" l
| Constructor_mismatch (ty, ty') ->
wrap_printing_env env (fun () ->
Printtyp.reset_and_mark_loops_list [ty; ty'];
fprintf ppf "@[<hov>%s %a@ %s@ %a@]"
"This variant type contains a constructor"
Printtyp.type_expr ty
"which should be"
Printtyp.type_expr ty')
| Not_a_variant ty ->
Printtyp.reset_and_mark_loops ty;
fprintf ppf "@[The type %a@ is not a polymorphic variant type@]"
Printtyp.type_expr ty;
begin match ty.desc with
| Tvar (Some s) ->
(* PR#7012: help the user that wrote 'Foo instead of `Foo *)
Misc.did_you_mean ppf (fun () -> ["`" ^ s])
| _ -> ()
end
| Variant_tags (lab1, lab2) ->
fprintf ppf
"@[Variant tags `%s@ and `%s have the same hash value.@ %s@]"
lab1 lab2 "Change one of them."
| Invalid_variable_name name ->
fprintf ppf "The type variable name %s is not allowed in programs" name
| Cannot_quantify (name, v) ->
fprintf ppf
"@[<hov>The universal type variable '%s cannot be generalized:@ %s.@]"
name
(if Btype.is_Tvar v then "it escapes its scope" else
if Btype.is_Tunivar v then "it is already bound to another variable"
else "it is not a variable")
| Multiple_constraints_on_type s ->
fprintf ppf "Multiple constraints for type %a" longident s
| Repeated_method_label s ->
fprintf ppf "@[This is the second method `%s' of this object type.@ %s@]"
s "Multiple occurences are not allowed."
| Unbound_value lid ->
fprintf ppf "Unbound value %a" longident lid;
spellcheck ppf fold_values env lid;
| Unbound_module lid ->
fprintf ppf "Unbound module %a" longident lid;
spellcheck ppf fold_modules env lid;
| Unbound_constructor lid ->
fprintf ppf "Unbound constructor %a" longident lid;
spellcheck ppf fold_constructors env lid;
| Unbound_label lid ->
fprintf ppf "Unbound record field %a" longident lid;
spellcheck ppf fold_labels env lid;
| Unbound_class lid ->
fprintf ppf "Unbound class %a" longident lid;
spellcheck ppf fold_classs env lid;
| Unbound_modtype lid ->
fprintf ppf "Unbound module type %a" longident lid;
spellcheck ppf fold_modtypes env lid;
| Unbound_cltype lid ->
fprintf ppf "Unbound class type %a" longident lid;
spellcheck ppf fold_cltypes env lid;
| Ill_typed_functor_application lid ->
fprintf ppf "Ill-typed functor application %a" longident lid
| Illegal_reference_to_recursive_module ->
fprintf ppf "Illegal recursive module reference"
| Access_functor_as_structure lid ->
fprintf ppf "The module %a is a functor, not a structure" longident lid
| Apply_structure_as_functor lid ->
fprintf ppf "The module %a is a structure, not a functor" longident lid
| Cannot_scrape_alias(lid, p) ->
fprintf ppf
"The module %a is an alias for module %a, which is missing"
longident lid path p
let () =
Location.register_error_of_exn
(function
| Error (loc, env, err) ->
Some (Location.error_of_printer loc (report_error env) err)
| Error_forward err ->
Some err
| _ ->
None
)