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https://github.com/CatalaLang/catala.git
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903 lines
33 KiB
OCaml
903 lines
33 KiB
OCaml
(* This file is part of the Catala compiler, a specification language for tax
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and social benefits computation rules. Copyright (C) 2020 Inria, contributor:
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Denis Merigoux <denis.merigoux@inria.fr>
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Licensed under the Apache License, Version 2.0 (the "License"); you may not
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use this file except in compliance with the License. You may obtain a copy of
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the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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License for the specific language governing permissions and limitations under
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the License. *)
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(** Typing for the default calculus. Because of the error terms, we perform type
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inference using the classical W algorithm with union-find unification. *)
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open Catala_utils
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module A = Definitions
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module Any =
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Uid.Make
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(struct
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type info = unit
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let to_string _ = "any"
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let format fmt () = Format.fprintf fmt "any"
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let equal _ _ = true
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let compare _ _ = 0
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end)
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()
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type unionfind_typ = naked_typ Marked.pos UnionFind.elem
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(** We do not reuse {!type: Shared_ast.typ} because we have to include a new
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[TAny] variant. Indeed, error terms can have any type and this has to be
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captured by the type sytem. *)
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and naked_typ =
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| TLit of A.typ_lit
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| TArrow of unionfind_typ list * unionfind_typ
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| TTuple of unionfind_typ list
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| TStruct of A.StructName.t
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| TEnum of A.EnumName.t
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| TOption of unionfind_typ
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| TArray of unionfind_typ
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| TAny of Any.t
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let rec typ_to_ast ~leave_unresolved (ty : unionfind_typ) : A.typ =
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let typ_to_ast = typ_to_ast ~leave_unresolved in
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let ty, pos = UnionFind.get (UnionFind.find ty) in
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match ty with
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| TLit l -> A.TLit l, pos
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| TTuple ts -> A.TTuple (List.map typ_to_ast ts), pos
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| TStruct s -> A.TStruct s, pos
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| TEnum e -> A.TEnum e, pos
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| TOption t -> A.TOption (typ_to_ast t), pos
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| TArrow (t1, t2) -> A.TArrow (List.map typ_to_ast t1, typ_to_ast t2), pos
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| TArray t1 -> A.TArray (typ_to_ast t1), pos
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| TAny _ ->
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if leave_unresolved then A.TAny, pos
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else
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(* No polymorphism in Catala: type inference should return full types
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without wildcards, and this function is used to recover the types after
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typing. *)
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Errors.raise_spanned_error pos
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"Internal error: typing at this point could not be resolved"
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(* Checks that there are no type variables remaining *)
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let rec all_resolved ty =
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match Marked.unmark (UnionFind.get (UnionFind.find ty)) with
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| TAny _ -> false
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| TLit _ | TStruct _ | TEnum _ -> true
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| TOption t1 | TArray t1 -> all_resolved t1
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| TArrow (t1, t2) -> List.for_all all_resolved t1 && all_resolved t2
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| TTuple ts -> List.for_all all_resolved ts
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let rec ast_to_typ (ty : A.typ) : unionfind_typ =
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let ty' =
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match Marked.unmark ty with
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| A.TLit l -> TLit l
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| A.TArrow (t1, t2) -> TArrow (List.map ast_to_typ t1, ast_to_typ t2)
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| A.TTuple ts -> TTuple (List.map ast_to_typ ts)
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| A.TStruct s -> TStruct s
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| A.TEnum e -> TEnum e
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| A.TOption t -> TOption (ast_to_typ t)
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| A.TArray t -> TArray (ast_to_typ t)
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| A.TAny -> TAny (Any.fresh ())
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in
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UnionFind.make (Marked.same_mark_as ty' ty)
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(** {1 Types and unification} *)
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let typ_needs_parens (t : unionfind_typ) : bool =
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let t = UnionFind.get (UnionFind.find t) in
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match Marked.unmark t with TArrow _ | TArray _ -> true | _ -> false
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let rec format_typ
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(ctx : A.decl_ctx)
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(fmt : Format.formatter)
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(naked_typ : unionfind_typ) : unit =
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let format_typ = format_typ ctx in
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let format_typ_with_parens (fmt : Format.formatter) (t : unionfind_typ) =
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if typ_needs_parens t then Format.fprintf fmt "(%a)" format_typ t
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else Format.fprintf fmt "%a" format_typ t
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in
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let naked_typ = UnionFind.get (UnionFind.find naked_typ) in
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match Marked.unmark naked_typ with
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| TLit l -> Format.fprintf fmt "%a" Print.tlit l
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| TTuple ts ->
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Format.fprintf fmt "@[<hov 2>(%a)@]"
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(Format.pp_print_list
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~pp_sep:(fun fmt () -> Format.fprintf fmt "@ *@ ")
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(fun fmt t -> Format.fprintf fmt "%a" format_typ t))
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ts
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| TStruct s -> Format.fprintf fmt "%a" A.StructName.format_t s
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| TEnum e -> Format.fprintf fmt "%a" A.EnumName.format_t e
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| TOption t ->
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Format.fprintf fmt "@[<hov 2>%a@ %s@]" format_typ_with_parens t "eoption"
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| TArrow ([t1], t2) ->
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Format.fprintf fmt "@[<hov 2>%a@ →@ %a@]" format_typ_with_parens t1
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format_typ t2
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| TArrow (t1, t2) ->
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Format.fprintf fmt "@[<hov 2>(%a)@ →@ %a@]"
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(Format.pp_print_list
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~pp_sep:(fun fmt () -> Format.fprintf fmt ",@ ")
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format_typ_with_parens)
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t1 format_typ t2
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| TArray t1 -> (
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match Marked.unmark (UnionFind.get (UnionFind.find t1)) with
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| TAny _ when not !Cli.debug_flag -> Format.pp_print_string fmt "collection"
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| _ -> Format.fprintf fmt "@[collection@ %a@]" format_typ t1)
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| TAny v ->
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if !Cli.debug_flag then Format.fprintf fmt "<a%d>" (Any.hash v)
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else Format.pp_print_string fmt "<any>"
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exception Type_error of A.any_expr * unionfind_typ * unionfind_typ
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type mark = { pos : Pos.t; uf : unionfind_typ }
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(** Raises an error if unification cannot be performed. The position annotation
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of the second [unionfind_typ] argument is propagated (unless it is [TAny]). *)
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let rec unify
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(ctx : A.decl_ctx)
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(e : ('a, 'm A.mark) A.gexpr) (* used for error context *)
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(t1 : unionfind_typ)
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(t2 : unionfind_typ) : unit =
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let unify = unify ctx in
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(* Cli.debug_format "Unifying %a and %a" (format_typ ctx) t1 (format_typ ctx)
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t2; *)
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let t1_repr = UnionFind.get (UnionFind.find t1) in
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let t2_repr = UnionFind.get (UnionFind.find t2) in
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let raise_type_error () = raise (Type_error (A.AnyExpr e, t1, t2)) in
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let () =
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match Marked.unmark t1_repr, Marked.unmark t2_repr with
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| TLit tl1, TLit tl2 -> if tl1 <> tl2 then raise_type_error ()
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| TArrow (t11, t12), TArrow (t21, t22) -> (
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unify e t12 t22;
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try List.iter2 (unify e) t11 t21
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with Invalid_argument _ -> raise_type_error ())
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| TTuple ts1, TTuple ts2 -> (
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try List.iter2 (unify e) ts1 ts2
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with Invalid_argument _ -> raise_type_error ())
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| TStruct s1, TStruct s2 ->
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if not (A.StructName.equal s1 s2) then raise_type_error ()
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| TEnum e1, TEnum e2 ->
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if not (A.EnumName.equal e1 e2) then raise_type_error ()
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| TOption t1, TOption t2 -> unify e t1 t2
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| TArray t1', TArray t2' -> unify e t1' t2'
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| TAny _, _ | _, TAny _ -> ()
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| ( ( TLit _ | TArrow _ | TTuple _ | TStruct _ | TEnum _ | TOption _
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| TArray _ ),
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_ ) ->
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raise_type_error ()
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in
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ignore
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@@ UnionFind.merge
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(fun t1 t2 -> match Marked.unmark t2 with TAny _ -> t1 | _ -> t2)
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t1 t2
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let handle_type_error ctx e t1 t2 =
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(* TODO: if we get weird error messages, then it means that we should use the
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persistent version of the union-find data structure. *)
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let pos =
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match e with
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| A.AnyExpr e -> (
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match Marked.get_mark e with Untyped { pos } | Typed { pos; _ } -> pos)
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in
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let t1_repr = UnionFind.get (UnionFind.find t1) in
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let t2_repr = UnionFind.get (UnionFind.find t2) in
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let t1_pos = Marked.get_mark t1_repr in
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let t2_pos = Marked.get_mark t2_repr in
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let unformat_typ typ =
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let buf = Buffer.create 59 in
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let ppf = Format.formatter_of_buffer buf in
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(* set infinite width to disable line cuts *)
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Format.pp_set_margin ppf max_int;
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format_typ ctx ppf typ;
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Format.pp_print_flush ppf ();
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Buffer.contents buf
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in
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let t1_s fmt () =
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Cli.format_with_style [ANSITerminal.yellow] fmt (unformat_typ t1)
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in
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let t2_s fmt () =
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Cli.format_with_style [ANSITerminal.yellow] fmt (unformat_typ t2)
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in
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Errors.raise_multispanned_error
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[
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( Some
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(Format.asprintf
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"Error coming from typechecking the following expression:"),
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pos );
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Some (Format.asprintf "Type %a coming from expression:" t1_s ()), t1_pos;
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Some (Format.asprintf "Type %a coming from expression:" t2_s ()), t2_pos;
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]
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"Error during typechecking, incompatible types:\n%a %a\n%a %a"
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(Cli.format_with_style [ANSITerminal.blue; ANSITerminal.Bold])
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"-->" t1_s ()
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(Cli.format_with_style [ANSITerminal.blue; ANSITerminal.Bold])
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"-->" t2_s ()
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let lit_type (lit : A.lit) : naked_typ =
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match lit with
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| LBool _ -> TLit TBool
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| LInt _ -> TLit TInt
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| LRat _ -> TLit TRat
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| LMoney _ -> TLit TMoney
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| LDate _ -> TLit TDate
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| LDuration _ -> TLit TDuration
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| LUnit -> TLit TUnit
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(** [op_type] and [resolve_overload] are a bit similar, and work on disjoint
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sets of operators. However, their assumptions are different so we keep the
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functions separate. In particular [resolve_overloads] requires its argument
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types to be known in advance. *)
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let polymorphic_op_type (op : Operator.polymorphic A.operator Marked.pos) :
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unionfind_typ =
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let open Operator in
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let pos = Marked.get_mark op in
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let any = lazy (UnionFind.make (TAny (Any.fresh ()), pos)) in
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let any2 = lazy (UnionFind.make (TAny (Any.fresh ()), pos)) in
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let bt = lazy (UnionFind.make (TLit TBool, pos)) in
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let it = lazy (UnionFind.make (TLit TInt, pos)) in
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let array a = lazy (UnionFind.make (TArray (Lazy.force a), pos)) in
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let ( @-> ) x y =
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lazy (UnionFind.make (TArrow (List.map Lazy.force x, Lazy.force y), pos))
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in
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let ty =
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match Marked.unmark op with
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| Fold -> [[any2; any] @-> any2; any2; array any] @-> any2
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| Eq -> [any; any] @-> bt
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| Map -> [[any] @-> any2; array any] @-> array any2
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| Filter -> [[any] @-> bt; array any] @-> array any
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| Reduce -> [[any; any] @-> any; any; array any] @-> any
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| Concat -> [array any; array any] @-> array any
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| Log (PosRecordIfTrueBool, _) -> [bt] @-> bt
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| Log _ -> [any] @-> any
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| Length -> [array any] @-> it
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in
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Lazy.force ty
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let resolve_overload_ret_type
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~leave_unresolved
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(ctx : A.decl_ctx)
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e
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(op : Operator.overloaded A.operator)
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tys : unionfind_typ =
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let op_ty =
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Operator.overload_type ctx
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(Marked.mark (Expr.pos e) op)
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(List.map (typ_to_ast ~leave_unresolved) tys)
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(* We use [unsafe] because the error is caught below *)
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in
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ast_to_typ (Type.arrow_return op_ty)
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(** {1 Double-directed typing} *)
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module Env = struct
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type 'e t = {
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structs : unionfind_typ A.StructField.Map.t A.StructName.Map.t;
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enums : unionfind_typ A.EnumConstructor.Map.t A.EnumName.Map.t;
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vars : ('e, unionfind_typ) Var.Map.t;
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scope_vars : A.typ A.ScopeVar.Map.t;
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scopes : A.typ A.ScopeVar.Map.t A.ScopeName.Map.t;
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toplevel_vars : A.typ A.TopdefName.Map.t;
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}
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let empty (decl_ctx : A.decl_ctx) =
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(* We fill the environment initially with the structs and enums
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declarations *)
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{
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structs =
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A.StructName.Map.map
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(A.StructField.Map.map ast_to_typ)
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decl_ctx.ctx_structs;
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enums =
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A.EnumName.Map.map
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(A.EnumConstructor.Map.map ast_to_typ)
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decl_ctx.ctx_enums;
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vars = Var.Map.empty;
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scope_vars = A.ScopeVar.Map.empty;
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scopes = A.ScopeName.Map.empty;
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toplevel_vars = A.TopdefName.Map.empty;
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}
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let get t v = Var.Map.find_opt v t.vars
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let get_scope_var t sv = A.ScopeVar.Map.find_opt sv t.scope_vars
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let get_toplevel_var t v = A.TopdefName.Map.find_opt v t.toplevel_vars
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let get_subscope_out_var t scope var =
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Option.bind (A.ScopeName.Map.find_opt scope t.scopes) (fun vmap ->
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A.ScopeVar.Map.find_opt var vmap)
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let add v tau t = { t with vars = Var.Map.add v tau t.vars }
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let add_var v typ t = add v (ast_to_typ typ) t
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let add_scope_var v typ t =
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{ t with scope_vars = A.ScopeVar.Map.add v typ t.scope_vars }
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let add_scope scope_name ~vars t =
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{ t with scopes = A.ScopeName.Map.add scope_name vars t.scopes }
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let add_toplevel_var v typ t =
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{ t with toplevel_vars = A.TopdefName.Map.add v typ t.toplevel_vars }
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let open_scope scope_name t =
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let scope_vars =
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A.ScopeVar.Map.union
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(fun _ _ -> assert false)
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t.scope_vars
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(A.ScopeName.Map.find scope_name t.scopes)
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in
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{ t with scope_vars }
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end
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let add_pos e ty = Marked.mark (Expr.pos e) ty
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let ty (_, { uf; _ }) = uf
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(** Infers the most permissive type from an expression *)
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let rec typecheck_expr_bottom_up :
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type a m.
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leave_unresolved:bool ->
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A.decl_ctx ->
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(a, m A.mark) A.gexpr Env.t ->
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(a, m A.mark) A.gexpr ->
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(a, mark) A.boxed_gexpr =
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fun ~leave_unresolved ctx env e ->
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typecheck_expr_top_down ~leave_unresolved ctx env
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(UnionFind.make (add_pos e (TAny (Any.fresh ()))))
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e
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(** Checks whether the expression can be typed with the provided type *)
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and typecheck_expr_top_down :
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type a m.
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leave_unresolved:bool ->
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A.decl_ctx ->
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(a, m A.mark) A.gexpr Env.t ->
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unionfind_typ ->
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(a, m A.mark) A.gexpr ->
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(a, mark) A.boxed_gexpr =
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fun ~leave_unresolved ctx env tau e ->
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(* Cli.debug_format "Propagating type %a for naked_expr %a" (format_typ ctx)
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tau (Expr.format ctx) e; *)
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let pos_e = Expr.pos e in
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let () =
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(* If there already is a type annotation on the given expr, ensure it
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matches *)
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match Marked.get_mark e with
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| A.Untyped _ | A.Typed { A.ty = A.TAny, _; _ } -> ()
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| A.Typed { A.ty; _ } -> unify ctx e tau (ast_to_typ ty)
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in
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let context_mark = { uf = tau; pos = pos_e } in
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let uf_mark uf =
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(* Unify with the supplied type first, and return the mark *)
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unify ctx e uf tau;
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{ uf; pos = pos_e }
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in
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let unionfind ?(pos = e) t = UnionFind.make (add_pos pos t) in
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let ty_mark ty = uf_mark (unionfind ty) in
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match Marked.unmark e with
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| A.ELocation loc ->
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let ty_opt =
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match loc with
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| DesugaredScopeVar (v, _) | ScopelangScopeVar v ->
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Env.get_scope_var env (Marked.unmark v)
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| SubScopeVar (scope, _, v) ->
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Env.get_subscope_out_var env scope (Marked.unmark v)
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| ToplevelVar v -> Env.get_toplevel_var env (Marked.unmark v)
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in
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let ty =
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match ty_opt with
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| Some ty -> ty
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| None ->
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Errors.raise_spanned_error pos_e "Reference to %a not found"
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(Expr.format ctx) e
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in
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Expr.elocation loc (uf_mark (ast_to_typ ty))
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| A.EStruct { name; fields } ->
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let mark = ty_mark (TStruct name) in
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let str_ast = A.StructName.Map.find name ctx.A.ctx_structs in
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let str = A.StructName.Map.find name env.structs in
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let _check_fields : unit =
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let missing_fields, extra_fields =
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A.StructField.Map.fold
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(fun fld x (remaining, extra) ->
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if A.StructField.Map.mem fld remaining then
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A.StructField.Map.remove fld remaining, extra
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else remaining, A.StructField.Map.add fld x extra)
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fields
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(str_ast, A.StructField.Map.empty)
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in
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let errs =
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List.map
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(fun (f, ty) ->
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( Some (Format.asprintf "Missing field %a" A.StructField.format_t f),
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Marked.get_mark ty ))
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(A.StructField.Map.bindings missing_fields)
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@ List.map
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(fun (f, ef) ->
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let dup = A.StructField.Map.mem f str in
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( Some
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(Format.asprintf "%s field %a"
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(if dup then "Duplicate" else "Unknown")
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|
A.StructField.format_t f),
|
|
Expr.pos ef ))
|
|
(A.StructField.Map.bindings extra_fields)
|
|
in
|
|
if errs <> [] then
|
|
Errors.raise_multispanned_error errs
|
|
"Mismatching field definitions for structure %a" A.StructName.format_t
|
|
name
|
|
in
|
|
let fields' =
|
|
A.StructField.Map.mapi
|
|
(fun f_name f_e ->
|
|
let f_ty = A.StructField.Map.find f_name str in
|
|
typecheck_expr_top_down ~leave_unresolved ctx env f_ty f_e)
|
|
fields
|
|
in
|
|
Expr.estruct name fields' mark
|
|
| A.EDStructAccess { e = e_struct; name_opt; field } ->
|
|
let t_struct =
|
|
match name_opt with
|
|
| Some name -> TStruct name
|
|
| None -> TAny (Any.fresh ())
|
|
in
|
|
let e_struct' =
|
|
typecheck_expr_top_down ~leave_unresolved ctx env (unionfind t_struct)
|
|
e_struct
|
|
in
|
|
let name =
|
|
match UnionFind.get (ty e_struct') with
|
|
| TStruct name, _ -> name
|
|
| TAny _, _ ->
|
|
Printf.ksprintf failwith
|
|
"Disambiguation failed before reaching field %s" field
|
|
| _ ->
|
|
Errors.raise_spanned_error (Expr.pos e)
|
|
"This is not a structure, cannot access field %s (%a)" field
|
|
(format_typ ctx) (ty e_struct')
|
|
in
|
|
let fld_ty =
|
|
let str =
|
|
try A.StructName.Map.find name env.structs
|
|
with Not_found ->
|
|
Errors.raise_spanned_error pos_e "No structure %a found"
|
|
A.StructName.format_t name
|
|
in
|
|
let field =
|
|
let candidate_structs =
|
|
try A.IdentName.Map.find field ctx.ctx_struct_fields
|
|
with Not_found ->
|
|
Errors.raise_spanned_error context_mark.pos
|
|
"Field %a does not belong to structure %a (no structure defines \
|
|
it)"
|
|
(Cli.format_with_style [ANSITerminal.yellow])
|
|
("\"" ^ field ^ "\"")
|
|
(Cli.format_with_style [ANSITerminal.yellow])
|
|
(Format.asprintf "\"%a\"" A.StructName.format_t name)
|
|
in
|
|
try A.StructName.Map.find name candidate_structs
|
|
with Not_found ->
|
|
Errors.raise_spanned_error context_mark.pos
|
|
"Field %a does not belong to structure %a, but to %a"
|
|
(Cli.format_with_style [ANSITerminal.yellow])
|
|
("\"" ^ field ^ "\"")
|
|
(Cli.format_with_style [ANSITerminal.yellow])
|
|
(Format.asprintf "\"%a\"" A.StructName.format_t name)
|
|
(Format.pp_print_list
|
|
~pp_sep:(fun ppf () -> Format.fprintf ppf "@ or@ ")
|
|
(fun fmt s_name ->
|
|
Format.fprintf fmt "%a"
|
|
(Cli.format_with_style [ANSITerminal.yellow])
|
|
(Format.asprintf "\"%a\"" A.StructName.format_t s_name)))
|
|
(List.map fst (A.StructName.Map.bindings candidate_structs))
|
|
in
|
|
A.StructField.Map.find field str
|
|
in
|
|
let mark = uf_mark fld_ty in
|
|
Expr.edstructaccess e_struct' field (Some name) mark
|
|
| A.EStructAccess { e = e_struct; name; field } ->
|
|
let fld_ty =
|
|
let str =
|
|
try A.StructName.Map.find name env.structs
|
|
with Not_found ->
|
|
Errors.raise_spanned_error pos_e "No structure %a found"
|
|
A.StructName.format_t name
|
|
in
|
|
try A.StructField.Map.find field str
|
|
with Not_found ->
|
|
Errors.raise_multispanned_error
|
|
[
|
|
None, pos_e;
|
|
( Some "Structure %a declared here",
|
|
Marked.get_mark (A.StructName.get_info name) );
|
|
]
|
|
"Structure %a doesn't define a field %a" A.StructName.format_t name
|
|
A.StructField.format_t field
|
|
in
|
|
let mark = uf_mark fld_ty in
|
|
let e_struct' =
|
|
typecheck_expr_top_down ~leave_unresolved ctx env
|
|
(unionfind (TStruct name)) e_struct
|
|
in
|
|
Expr.estructaccess e_struct' field name mark
|
|
| A.EInj { name; cons; e = e_enum } ->
|
|
let mark = uf_mark (unionfind (TEnum name)) in
|
|
let e_enum' =
|
|
typecheck_expr_top_down ~leave_unresolved ctx env
|
|
(A.EnumConstructor.Map.find cons (A.EnumName.Map.find name env.enums))
|
|
e_enum
|
|
in
|
|
Expr.einj e_enum' cons name mark
|
|
| A.EMatch { e = e1; name; cases } ->
|
|
let cases_ty = A.EnumName.Map.find name ctx.A.ctx_enums in
|
|
let t_ret = unionfind ~pos:e1 (TAny (Any.fresh ())) in
|
|
let mark = uf_mark t_ret in
|
|
let e1' =
|
|
typecheck_expr_top_down ~leave_unresolved ctx env (unionfind (TEnum name))
|
|
e1
|
|
in
|
|
let cases' =
|
|
A.EnumConstructor.Map.mapi
|
|
(fun c_name e ->
|
|
let c_ty = A.EnumConstructor.Map.find c_name cases_ty in
|
|
(* For now our constructors are limited to zero or one argument. If
|
|
there is a change to allow for multiple arguments, it might be
|
|
easier to use tuples directly. *)
|
|
let e_ty = unionfind ~pos:e (TArrow ([ast_to_typ c_ty], t_ret)) in
|
|
typecheck_expr_top_down ~leave_unresolved ctx env e_ty e)
|
|
cases
|
|
in
|
|
Expr.ematch e1' name cases' mark
|
|
| A.EScopeCall { scope; args } ->
|
|
let scope_out_struct =
|
|
(A.ScopeName.Map.find scope ctx.ctx_scopes).out_struct_name
|
|
in
|
|
let mark = uf_mark (unionfind (TStruct scope_out_struct)) in
|
|
let vars = A.ScopeName.Map.find scope env.scopes in
|
|
let args' =
|
|
A.ScopeVar.Map.mapi
|
|
(fun name ->
|
|
typecheck_expr_top_down ~leave_unresolved ctx env
|
|
(ast_to_typ (A.ScopeVar.Map.find name vars)))
|
|
args
|
|
in
|
|
Expr.escopecall scope args' mark
|
|
| A.ERaise ex -> Expr.eraise ex context_mark
|
|
| A.ECatch { body; exn; handler } ->
|
|
let body' = typecheck_expr_top_down ~leave_unresolved ctx env tau body in
|
|
let handler' =
|
|
typecheck_expr_top_down ~leave_unresolved ctx env tau handler
|
|
in
|
|
Expr.ecatch body' exn handler' context_mark
|
|
| A.EVar v ->
|
|
let tau' =
|
|
match Env.get env v with
|
|
| Some t -> t
|
|
| None ->
|
|
Errors.raise_spanned_error pos_e
|
|
"Variable %s not found in the current context" (Bindlib.name_of v)
|
|
in
|
|
Expr.evar (Var.translate v) (uf_mark tau')
|
|
| A.ELit lit -> Expr.elit lit (ty_mark (lit_type lit))
|
|
| A.ETuple es ->
|
|
let tys = List.map (fun _ -> unionfind (TAny (Any.fresh ()))) es in
|
|
let mark = uf_mark (unionfind (TTuple tys)) in
|
|
let es' =
|
|
List.map2 (typecheck_expr_top_down ~leave_unresolved ctx env) tys es
|
|
in
|
|
Expr.etuple es' mark
|
|
| A.ETupleAccess { e = e1; index; size } ->
|
|
if index >= size then
|
|
Errors.raise_spanned_error (Expr.pos e)
|
|
"Tuple access out of bounds (%d/%d)" index size;
|
|
let tuple_ty =
|
|
TTuple
|
|
(List.init size (fun n ->
|
|
if n = index then tau else unionfind ~pos:e1 (TAny (Any.fresh ()))))
|
|
in
|
|
let e1' =
|
|
typecheck_expr_top_down ~leave_unresolved ctx env
|
|
(unionfind ~pos:e1 tuple_ty)
|
|
e1
|
|
in
|
|
Expr.etupleaccess e1' index size context_mark
|
|
| A.EAbs { binder; tys = t_args } ->
|
|
if Bindlib.mbinder_arity binder <> List.length t_args then
|
|
Errors.raise_spanned_error (Expr.pos e)
|
|
"function has %d variables but was supplied %d types"
|
|
(Bindlib.mbinder_arity binder)
|
|
(List.length t_args)
|
|
else
|
|
let tau_args = List.map ast_to_typ t_args in
|
|
let t_ret = unionfind (TAny (Any.fresh ())) in
|
|
let t_func = unionfind (TArrow (tau_args, t_ret)) in
|
|
let mark = uf_mark t_func in
|
|
if not leave_unresolved then assert (List.for_all all_resolved tau_args);
|
|
let xs, body = Bindlib.unmbind binder in
|
|
let xs' = Array.map Var.translate xs in
|
|
let env =
|
|
List.fold_left2
|
|
(fun env x tau_arg -> Env.add x tau_arg env)
|
|
env (Array.to_list xs) tau_args
|
|
in
|
|
let body' =
|
|
typecheck_expr_top_down ~leave_unresolved ctx env t_ret body
|
|
in
|
|
let binder' = Bindlib.bind_mvar xs' (Expr.Box.lift body') in
|
|
Expr.eabs binder' (List.map (typ_to_ast ~leave_unresolved) tau_args) mark
|
|
| A.EApp { f = (EOp { op; tys }, _) as e1; args } ->
|
|
let t_args = List.map ast_to_typ tys in
|
|
let t_func = unionfind (TArrow (t_args, tau)) in
|
|
let e1', args' =
|
|
Operator.kind_dispatch op
|
|
~polymorphic:(fun _ ->
|
|
(* Type the operator first, then right-to-left: polymorphic operators
|
|
are required to allow the resolution of all type variables this
|
|
way *)
|
|
let e1' =
|
|
typecheck_expr_top_down ~leave_unresolved ctx env t_func e1
|
|
in
|
|
let args' =
|
|
List.rev_map2
|
|
(typecheck_expr_top_down ~leave_unresolved ctx env)
|
|
(List.rev t_args) (List.rev args)
|
|
in
|
|
e1', args')
|
|
~overloaded:(fun _ ->
|
|
(* Typing the arguments first is required to resolve the operator *)
|
|
let args' =
|
|
List.map2
|
|
(typecheck_expr_top_down ~leave_unresolved ctx env)
|
|
t_args args
|
|
in
|
|
let e1' =
|
|
typecheck_expr_top_down ~leave_unresolved ctx env t_func e1
|
|
in
|
|
e1', args')
|
|
~monomorphic:(fun _ ->
|
|
(* Here it doesn't matter but may affect the error messages *)
|
|
let e1' =
|
|
typecheck_expr_top_down ~leave_unresolved ctx env t_func e1
|
|
in
|
|
let args' =
|
|
List.map2
|
|
(typecheck_expr_top_down ~leave_unresolved ctx env)
|
|
t_args args
|
|
in
|
|
e1', args')
|
|
~resolved:(fun _ ->
|
|
(* This case should not fail *)
|
|
let e1' =
|
|
typecheck_expr_top_down ~leave_unresolved ctx env t_func e1
|
|
in
|
|
let args' =
|
|
List.map2
|
|
(typecheck_expr_top_down ~leave_unresolved ctx env)
|
|
t_args args
|
|
in
|
|
e1', args')
|
|
in
|
|
Expr.eapp e1' args' context_mark
|
|
| A.EApp { f = e1; args } ->
|
|
(* Here we type the arguments first (in order), to ensure we know the types
|
|
of the arguments if [f] is [EAbs] before disambiguation. This is also the
|
|
right order for the [let-in] form. *)
|
|
let t_args = List.map (fun _ -> unionfind (TAny (Any.fresh ()))) args in
|
|
let t_func = unionfind (TArrow (t_args, tau)) in
|
|
let args' =
|
|
List.map2 (typecheck_expr_top_down ~leave_unresolved ctx env) t_args args
|
|
in
|
|
let e1' = typecheck_expr_top_down ~leave_unresolved ctx env t_func e1 in
|
|
Expr.eapp e1' args' context_mark
|
|
| A.EOp { op; tys } ->
|
|
let tys' = List.map ast_to_typ tys in
|
|
let t_ret = unionfind (TAny (Any.fresh ())) in
|
|
let t_func = unionfind (TArrow (tys', t_ret)) in
|
|
unify ctx e t_func tau;
|
|
let tys, mark =
|
|
Operator.kind_dispatch op
|
|
~polymorphic:(fun op ->
|
|
tys, uf_mark (polymorphic_op_type (Marked.mark pos_e op)))
|
|
~monomorphic:(fun op ->
|
|
let mark =
|
|
uf_mark
|
|
(ast_to_typ (Operator.monomorphic_type (Marked.mark pos_e op)))
|
|
in
|
|
List.map (typ_to_ast ~leave_unresolved) tys', mark)
|
|
~overloaded:(fun op ->
|
|
unify ctx e t_ret
|
|
(resolve_overload_ret_type ~leave_unresolved ctx e op tys');
|
|
( List.map (typ_to_ast ~leave_unresolved) tys',
|
|
{ uf = t_func; pos = pos_e } ))
|
|
~resolved:(fun op ->
|
|
let mark =
|
|
uf_mark (ast_to_typ (Operator.resolved_type (Marked.mark pos_e op)))
|
|
in
|
|
List.map (typ_to_ast ~leave_unresolved) tys', mark)
|
|
in
|
|
Expr.eop op tys mark
|
|
| A.EDefault { excepts; just; cons } ->
|
|
let cons' = typecheck_expr_top_down ~leave_unresolved ctx env tau cons in
|
|
let just' =
|
|
typecheck_expr_top_down ~leave_unresolved ctx env
|
|
(unionfind ~pos:just (TLit TBool))
|
|
just
|
|
in
|
|
let excepts' =
|
|
List.map (typecheck_expr_top_down ~leave_unresolved ctx env tau) excepts
|
|
in
|
|
Expr.edefault excepts' just' cons' context_mark
|
|
| A.EIfThenElse { cond; etrue = et; efalse = ef } ->
|
|
let et' = typecheck_expr_top_down ~leave_unresolved ctx env tau et in
|
|
let ef' = typecheck_expr_top_down ~leave_unresolved ctx env tau ef in
|
|
let cond' =
|
|
typecheck_expr_top_down ~leave_unresolved ctx env
|
|
(unionfind ~pos:cond (TLit TBool))
|
|
cond
|
|
in
|
|
Expr.eifthenelse cond' et' ef' context_mark
|
|
| A.EAssert e1 ->
|
|
let mark = uf_mark (unionfind (TLit TUnit)) in
|
|
let e1' =
|
|
typecheck_expr_top_down ~leave_unresolved ctx env
|
|
(unionfind ~pos:e1 (TLit TBool))
|
|
e1
|
|
in
|
|
Expr.eassert e1' mark
|
|
| A.EEmptyError -> Expr.eemptyerror (ty_mark (TAny (Any.fresh ())))
|
|
| A.EErrorOnEmpty e1 ->
|
|
let e1' = typecheck_expr_top_down ~leave_unresolved ctx env tau e1 in
|
|
Expr.eerroronempty e1' context_mark
|
|
| A.EArray es ->
|
|
let cell_type = unionfind (TAny (Any.fresh ())) in
|
|
let mark = uf_mark (unionfind (TArray cell_type)) in
|
|
let es' =
|
|
List.map (typecheck_expr_top_down ~leave_unresolved ctx env cell_type) es
|
|
in
|
|
Expr.earray es' mark
|
|
|
|
let wrap ctx f e =
|
|
try f e
|
|
with Type_error (e, ty1, ty2) -> (
|
|
let bt = Printexc.get_raw_backtrace () in
|
|
try handle_type_error ctx e ty1 ty2
|
|
with e -> Printexc.raise_with_backtrace e bt)
|
|
|
|
let wrap_expr ctx f e =
|
|
(* We need to unbox here, because the typing may otherwise be stored in
|
|
Bindlib closures and not yet applied, and would escape the `try..with` *)
|
|
wrap ctx (fun e -> Expr.unbox (f e)) e
|
|
|
|
(** {1 API} *)
|
|
|
|
let get_ty_mark ~leave_unresolved { uf; pos } =
|
|
A.Typed { ty = typ_to_ast ~leave_unresolved uf; pos }
|
|
|
|
let expr_raw
|
|
(type a)
|
|
~(leave_unresolved : bool)
|
|
(ctx : A.decl_ctx)
|
|
?(env = Env.empty ctx)
|
|
?(typ : A.typ option)
|
|
(e : (a, 'm) A.gexpr) : (a, mark) A.gexpr =
|
|
let fty =
|
|
match typ with
|
|
| None -> typecheck_expr_bottom_up ~leave_unresolved ctx env
|
|
| Some typ ->
|
|
typecheck_expr_top_down ~leave_unresolved ctx env (ast_to_typ typ)
|
|
in
|
|
wrap_expr ctx fty e
|
|
|
|
let check_expr ~leave_unresolved ctx ?env ?typ e =
|
|
Expr.map_marks
|
|
~f:(fun { pos; _ } -> A.Untyped { pos })
|
|
(expr_raw ctx ~leave_unresolved ?env ?typ e)
|
|
|
|
(* Infer the type of an expression *)
|
|
let expr ~leave_unresolved ctx ?env ?typ e =
|
|
Expr.map_marks
|
|
~f:(get_ty_mark ~leave_unresolved)
|
|
(expr_raw ~leave_unresolved ctx ?env ?typ e)
|
|
|
|
let rec scope_body_expr ~leave_unresolved ctx env ty_out body_expr =
|
|
match body_expr with
|
|
| A.Result e ->
|
|
let e' =
|
|
wrap_expr ctx (typecheck_expr_top_down ~leave_unresolved ctx env ty_out) e
|
|
in
|
|
let e' = Expr.map_marks ~f:(get_ty_mark ~leave_unresolved) e' in
|
|
Bindlib.box_apply (fun e -> A.Result e) (Expr.Box.lift e')
|
|
| A.ScopeLet
|
|
{
|
|
scope_let_kind;
|
|
scope_let_typ;
|
|
scope_let_expr = e0;
|
|
scope_let_next;
|
|
scope_let_pos;
|
|
} ->
|
|
let ty_e = ast_to_typ scope_let_typ in
|
|
let e =
|
|
wrap_expr ctx (typecheck_expr_bottom_up ~leave_unresolved ctx env) e0
|
|
in
|
|
wrap ctx (fun t -> unify ctx e0 (ty e) t) ty_e;
|
|
(* We could use [typecheck_expr_top_down] rather than this manual
|
|
unification, but we get better messages with this order of the [unify]
|
|
parameters, which keeps location of the type as defined instead of as
|
|
inferred. *)
|
|
let var, next = Bindlib.unbind scope_let_next in
|
|
let env = Env.add var ty_e env in
|
|
let next = scope_body_expr ~leave_unresolved ctx env ty_out next in
|
|
let scope_let_next = Bindlib.bind_var (Var.translate var) next in
|
|
Bindlib.box_apply2
|
|
(fun scope_let_expr scope_let_next ->
|
|
A.ScopeLet
|
|
{
|
|
scope_let_kind;
|
|
scope_let_typ =
|
|
(match Marked.unmark scope_let_typ with
|
|
| TAny -> typ_to_ast ~leave_unresolved (ty e)
|
|
| _ -> scope_let_typ);
|
|
scope_let_expr;
|
|
scope_let_next;
|
|
scope_let_pos;
|
|
})
|
|
(Expr.Box.lift (Expr.map_marks ~f:(get_ty_mark ~leave_unresolved) e))
|
|
scope_let_next
|
|
|
|
let scope_body ~leave_unresolved ctx env body =
|
|
let get_pos struct_name =
|
|
Marked.get_mark (A.StructName.get_info struct_name)
|
|
in
|
|
let struct_ty struct_name =
|
|
UnionFind.make (Marked.mark (get_pos struct_name) (TStruct struct_name))
|
|
in
|
|
let ty_in = struct_ty body.A.scope_body_input_struct in
|
|
let ty_out = struct_ty body.A.scope_body_output_struct in
|
|
let var, e = Bindlib.unbind body.A.scope_body_expr in
|
|
let env = Env.add var ty_in env in
|
|
let e' = scope_body_expr ~leave_unresolved ctx env ty_out e in
|
|
( Bindlib.box_apply
|
|
(fun scope_body_expr -> { body with scope_body_expr })
|
|
(Bindlib.bind_var (Var.translate var) e'),
|
|
UnionFind.make
|
|
(Marked.mark
|
|
(get_pos body.A.scope_body_output_struct)
|
|
(TArrow ([ty_in], ty_out))) )
|
|
|
|
let rec scopes ~leave_unresolved ctx env = function
|
|
| A.Nil -> Bindlib.box A.Nil
|
|
| A.Cons (item, next_bind) ->
|
|
let var, next = Bindlib.unbind next_bind in
|
|
let env, def =
|
|
match item with
|
|
| A.ScopeDef (name, body) ->
|
|
let body_e, ty_scope = scope_body ~leave_unresolved ctx env body in
|
|
( Env.add var ty_scope env,
|
|
Bindlib.box_apply (fun body -> A.ScopeDef (name, body)) body_e )
|
|
| A.Topdef (name, typ, e) ->
|
|
let e' = expr_raw ~leave_unresolved ctx ~env ~typ e in
|
|
let uf = (Marked.get_mark e').uf in
|
|
let e' = Expr.map_marks ~f:(get_ty_mark ~leave_unresolved) e' in
|
|
( Env.add var uf env,
|
|
Bindlib.box_apply
|
|
(fun e -> A.Topdef (name, typ, e))
|
|
(Expr.Box.lift e') )
|
|
in
|
|
let next' = scopes ~leave_unresolved ctx env next in
|
|
let next_bind' = Bindlib.bind_var (Var.translate var) next' in
|
|
Bindlib.box_apply2 (fun item next -> A.Cons (item, next)) def next_bind'
|
|
|
|
let program ~leave_unresolved prg =
|
|
let code_items =
|
|
Bindlib.unbox
|
|
(scopes ~leave_unresolved prg.A.decl_ctx (Env.empty prg.A.decl_ctx)
|
|
prg.A.code_items)
|
|
in
|
|
{ prg with code_items }
|