1 files changed, 145 insertions, 45 deletions

diff --git a/compiler/PureUtils.ml b/compiler/PureUtils.ml
index 1c8d8921..3aeabffe 100644
--- a/compiler/PureUtils.ml
+++ b/compiler/PureUtils.ml
@@ -89,14 +89,31 @@ let mk_mplace (var_id : E.VarId.id) (name : string option)
     (projection : mprojection) : mplace =
   { var_id; name; projection }
 
+let empty_generic_params : generic_params =
+  { types = []; const_generics = []; trait_clauses = [] }
+
+let empty_generic_args : generic_args =
+  { types = []; const_generics = []; trait_refs = [] }
+
+let mk_generic_args_from_types (types : ty list) : generic_args =
+  { types; const_generics = []; trait_refs = [] }
+
+type subst = {
+  ty_subst : TypeVarId.id -> ty;
+  cg_subst : ConstGenericVarId.id -> const_generic;
+  tr_subst : TraitClauseId.id -> trait_instance_id;
+  tr_self : trait_instance_id;
+}
+
 (** Type substitution *)
-let ty_substitute (tsubst : TypeVarId.id -> ty)
-    (cgsubst : ConstGenericVarId.id -> const_generic) (ty : ty) : ty =
+let ty_substitute (subst : subst) (ty : ty) : ty =
   let obj =
     object
       inherit [_] map_ty
-      method! visit_TypeVar _ var_id = tsubst var_id
-      method! visit_ConstGenericVar _ var_id = cgsubst var_id
+      method! visit_TypeVar _ var_id = subst.ty_subst var_id
+      method! visit_ConstGenericVar _ var_id = subst.cg_subst var_id
+      method! visit_Clause _ id = subst.tr_subst id
+      method! visit_Self _ = subst.tr_self
     end
   in
   obj#visit_ty () ty
@@ -115,6 +132,18 @@ let make_const_generic_subst (vars : const_generic_var list)
     (cgs : const_generic list) : ConstGenericVarId.id -> const_generic =
   Substitute.make_const_generic_subst_from_vars vars cgs
 
+let make_trait_subst (clauses : trait_clause list) (refs : trait_ref list) :
+    TraitClauseId.id -> trait_instance_id =
+  let clauses = List.map (fun x -> x.clause_id) clauses in
+  let refs = List.map (fun x -> TraitRef x) refs in
+  let ls = List.combine clauses refs in
+  let mp =
+    List.fold_left
+      (fun mp (k, v) -> TraitClauseId.Map.add k v mp)
+      TraitClauseId.Map.empty ls
+  in
+  fun id -> TraitClauseId.Map.find id mp
+
 (** Retrieve the list of fields for the given variant of a {!type:Aeneas.Pure.type_decl}.
 
     Raises [Invalid_argument] if the arguments are incorrect.
@@ -135,20 +164,27 @@ let type_decl_get_fields (def : type_decl)
              - def: " ^ show_type_decl def ^ "\n- opt_variant_id: "
           ^ opt_variant_id))
 
+let make_subst_from_generics (params : generic_params) (args : generic_args)
+    (tr_self : trait_instance_id) : subst =
+  let ty_subst = make_type_subst params.types args.types in
+  let cg_subst =
+    make_const_generic_subst params.const_generics args.const_generics
+  in
+  let tr_subst = make_trait_subst params.trait_clauses args.trait_refs in
+  { ty_subst; cg_subst; tr_subst; tr_self }
+
 (** Instantiate the type variables for the chosen variant in an ADT definition,
     and return the list of the types of its fields *)
 let type_decl_get_instantiated_fields_types (def : type_decl)
-    (opt_variant_id : VariantId.id option) (types : ty list)
-    (cgs : const_generic list) : ty list =
-  let ty_subst = make_type_subst def.type_params types in
-  let cg_subst = make_const_generic_subst def.const_generic_params cgs in
+    (opt_variant_id : VariantId.id option) (generics : generic_args) : ty list =
+  (* There shouldn't be any reference to Self *)
+  let tr_self = UnknownTrait __FUNCTION__ in
+  let subst = make_subst_from_generics def.generics generics tr_self in
   let fields = type_decl_get_fields def opt_variant_id in
-  List.map (fun f -> ty_substitute ty_subst cg_subst f.field_ty) fields
+  List.map (fun f -> ty_substitute subst f.field_ty) fields
 
-let fun_sig_substitute (tsubst : TypeVarId.id -> ty)
-    (cgsubst : ConstGenericVarId.id -> const_generic) (sg : fun_sig) :
-    inst_fun_sig =
-  let subst = ty_substitute tsubst cgsubst in
+let fun_sig_substitute (subst : subst) (sg : fun_sig) : inst_fun_sig =
+  let subst = ty_substitute subst in
   let inputs = List.map subst sg.inputs in
   let output = subst sg.output in
   let doutputs = List.map subst sg.doutputs in
@@ -164,7 +200,8 @@ let fun_sig_substitute (tsubst : TypeVarId.id -> ty)
  *)
 let rec let_group_requires_parentheses (e : texpression) : bool =
   match e.e with
-  | Var _ | Const _ | App _ | Abs _ | Qualif _ | StructUpdate _ -> false
+  | Var _ | CVar _ | Const _ | App _ | Abs _ | Qualif _ | StructUpdate _ ->
+      false
   | Let (monadic, _, _, next_e) ->
       if monadic then true else let_group_requires_parentheses next_e
   | Switch (_, _) -> false
@@ -184,15 +221,18 @@ let is_var (e : texpression) : bool =
 let as_var (e : texpression) : VarId.id =
   match e.e with Var v -> v | _ -> raise (Failure "Unreachable")
 
+let is_cvar (e : texpression) : bool =
+  match e.e with CVar _ -> true | _ -> false
+
 let is_global (e : texpression) : bool =
   match e.e with Qualif { id = Global _; _ } -> true | _ -> false
 
 let is_const (e : texpression) : bool =
   match e.e with Const _ -> true | _ -> false
 
-let ty_as_adt (ty : ty) : type_id * ty list * const_generic list =
+let ty_as_adt (ty : ty) : type_id * generic_args =
   match ty with
-  | Adt (id, tys, cgs) -> (id, tys, cgs)
+  | Adt (id, generics) -> (id, generics)
   | _ -> raise (Failure "Unreachable")
 
 (** Remove the external occurrences of {!Meta} *)
@@ -290,28 +330,30 @@ let destruct_qualif_app (e : texpression) : qualif * texpression list =
 
 (** Destruct an expression into a function call, if possible *)
 let opt_destruct_function_call (e : texpression) :
-    (fun_or_op_id * ty list * texpression list) option =
+    (fun_or_op_id * generic_args * texpression list) option =
   match opt_destruct_qualif_app e with
   | None -> None
   | Some (qualif, args) -> (
       match qualif.id with
-      | FunOrOp fun_id -> Some (fun_id, qualif.type_args, args)
+      | FunOrOp fun_id -> Some (fun_id, qualif.generics, args)
       | _ -> None)
 
 let opt_destruct_result (ty : ty) : ty option =
   match ty with
-  | Adt (Assumed Result, tys, cgs) ->
-      assert (cgs = []);
-      Some (Collections.List.to_cons_nil tys)
+  | Adt (Assumed Result, generics) ->
+      assert (generics.const_generics = []);
+      assert (generics.trait_refs = []);
+      Some (Collections.List.to_cons_nil generics.types)
   | _ -> None
 
 let destruct_result (ty : ty) : ty = Option.get (opt_destruct_result ty)
 
 let opt_destruct_tuple (ty : ty) : ty list option =
   match ty with
-  | Adt (Tuple, tys, cgs) ->
-      assert (cgs = []);
-      Some tys
+  | Adt (Tuple, generics) ->
+      assert (generics.const_generics = []);
+      assert (generics.trait_refs = []);
+      Some generics.types
   | _ -> None
 
 let mk_abs (x : typed_pattern) (e : texpression) : texpression =
@@ -383,14 +425,16 @@ let mk_switch (scrut : texpression) (sb : switch_body) : texpression =
     - if there is > one type: wrap them in a tuple
  *)
 let mk_simpl_tuple_ty (tys : ty list) : ty =
-  match tys with [ ty ] -> ty | _ -> Adt (Tuple, tys, [])
+  match tys with
+  | [ ty ] -> ty
+  | _ -> Adt (Tuple, mk_generic_args_from_types tys)
 
 let mk_bool_ty : ty = Literal Bool
-let mk_unit_ty : ty = Adt (Tuple, [], [])
+let mk_unit_ty : ty = Adt (Tuple, empty_generic_args)
 
 let mk_unit_rvalue : texpression =
   let id = AdtCons { adt_id = Tuple; variant_id = None } in
-  let qualif = { id; type_args = []; const_generic_args = [] } in
+  let qualif = { id; generics = empty_generic_args } in
   let e = Qualif qualif in
   let ty = mk_unit_ty in
   { e; ty }
@@ -430,7 +474,7 @@ let mk_simpl_tuple_pattern (vl : typed_pattern list) : typed_pattern =
   | [ v ] -> v
   | _ ->
       let tys = List.map (fun (v : typed_pattern) -> v.ty) vl in
-      let ty = Adt (Tuple, tys, []) in
+      let ty = Adt (Tuple, mk_generic_args_from_types tys) in
       let value = PatAdt { variant_id = None; field_values = vl } in
       { value; ty }
 
@@ -441,11 +485,11 @@ let mk_simpl_tuple_texpression (vl : texpression list) : texpression =
   | _ ->
       (* Compute the types of the fields, and the type of the tuple constructor *)
       let tys = List.map (fun (v : texpression) -> v.ty) vl in
-      let ty = Adt (Tuple, tys, []) in
+      let ty = Adt (Tuple, mk_generic_args_from_types tys) in
       let ty = mk_arrows tys ty in
       (* Construct the tuple constructor qualifier *)
       let id = AdtCons { adt_id = Tuple; variant_id = None } in
-      let qualif = { id; type_args = tys; const_generic_args = [] } in
+      let qualif = { id; generics = mk_generic_args_from_types tys } in
       (* Put everything together *)
       let cons = { e = Qualif qualif; ty } in
       mk_apps cons vl
@@ -463,32 +507,36 @@ let ty_as_integer (t : ty) : T.integer_type =
 let ty_as_literal (t : ty) : T.literal_type =
   match t with Literal ty -> ty | _ -> raise (Failure "Unreachable")
 
-let mk_state_ty : ty = Adt (Assumed State, [], [])
-let mk_result_ty (ty : ty) : ty = Adt (Assumed Result, [ ty ], [])
-let mk_error_ty : ty = Adt (Assumed Error, [], [])
-let mk_fuel_ty : ty = Adt (Assumed Fuel, [], [])
+let mk_state_ty : ty = Adt (Assumed State, empty_generic_args)
+
+let mk_result_ty (ty : ty) : ty =
+  Adt (Assumed Result, mk_generic_args_from_types [ ty ])
+
+let mk_error_ty : ty = Adt (Assumed Error, empty_generic_args)
+let mk_fuel_ty : ty = Adt (Assumed Fuel, empty_generic_args)
 
 let mk_error (error : VariantId.id) : texpression =
   let ty = mk_error_ty in
   let id = AdtCons { adt_id = Assumed Error; variant_id = Some error } in
-  let qualif = { id; type_args = []; const_generic_args = [] } in
+  let qualif = { id; generics = empty_generic_args } in
   let e = Qualif qualif in
   { e; ty }
 
 let unwrap_result_ty (ty : ty) : ty =
   match ty with
-  | Adt (Assumed Result, [ ty ], cgs) ->
-      assert (cgs = []);
+  | Adt
+      (Assumed Result, { types = [ ty ]; const_generics = []; trait_refs = [] })
+    ->
       ty
   | _ -> raise (Failure "not a result type")
 
 let mk_result_fail_texpression (error : texpression) (ty : ty) : texpression =
   let type_args = [ ty ] in
-  let ty = Adt (Assumed Result, type_args, []) in
+  let ty = Adt (Assumed Result, mk_generic_args_from_types type_args) in
   let id =
     AdtCons { adt_id = Assumed Result; variant_id = Some result_fail_id }
   in
-  let qualif = { id; type_args; const_generic_args = [] } in
+  let qualif = { id; generics = mk_generic_args_from_types type_args } in
   let cons_e = Qualif qualif in
   let cons_ty = mk_arrow error.ty ty in
   let cons = { e = cons_e; ty = cons_ty } in
@@ -501,11 +549,11 @@ let mk_result_fail_texpression_with_error_id (error : VariantId.id) (ty : ty) :
 
 let mk_result_return_texpression (v : texpression) : texpression =
   let type_args = [ v.ty ] in
-  let ty = Adt (Assumed Result, type_args, []) in
+  let ty = Adt (Assumed Result, mk_generic_args_from_types type_args) in
   let id =
     AdtCons { adt_id = Assumed Result; variant_id = Some result_return_id }
   in
-  let qualif = { id; type_args; const_generic_args = [] } in
+  let qualif = { id; generics = mk_generic_args_from_types type_args } in
   let cons_e = Qualif qualif in
   let cons_ty = mk_arrow v.ty ty in
   let cons = { e = cons_e; ty = cons_ty } in
@@ -514,7 +562,7 @@ let mk_result_return_texpression (v : texpression) : texpression =
 (** Create a [Fail err] pattern which captures the error *)
 let mk_result_fail_pattern (error_pat : pattern) (ty : ty) : typed_pattern =
   let error_pat : typed_pattern = { value = error_pat; ty = mk_error_ty } in
-  let ty = Adt (Assumed Result, [ ty ], []) in
+  let ty = Adt (Assumed Result, mk_generic_args_from_types [ ty ]) in
   let value =
     PatAdt { variant_id = Some result_fail_id; field_values = [ error_pat ] }
   in
@@ -526,7 +574,7 @@ let mk_result_fail_pattern_ignore_error (ty : ty) : typed_pattern =
   mk_result_fail_pattern error_pat ty
 
 let mk_result_return_pattern (v : typed_pattern) : typed_pattern =
-  let ty = Adt (Assumed Result, [ v.ty ], []) in
+  let ty = Adt (Assumed Result, mk_generic_args_from_types [ v.ty ]) in
   let value =
     PatAdt { variant_id = Some result_return_id; field_values = [ v ] }
   in
@@ -561,11 +609,11 @@ let rec typed_pattern_to_texpression (pat : typed_pattern) : texpression option
           let fields_values = List.map (fun e -> Option.get e) fields in
 
           (* Retrieve the type id and the type args from the pat type (simpler this way *)
-          let adt_id, type_args, const_generic_args = ty_as_adt pat.ty in
+          let adt_id, generics = ty_as_adt pat.ty in
 
           (* Create the constructor *)
           let qualif_id = AdtCons { adt_id; variant_id = av.variant_id } in
-          let qualif = { id = qualif_id; type_args; const_generic_args } in
+          let qualif = { id = qualif_id; generics } in
           let cons_e = Qualif qualif in
           let field_tys =
             List.map (fun (v : texpression) -> v.ty) fields_values
@@ -577,3 +625,55 @@ let rec typed_pattern_to_texpression (pat : typed_pattern) : texpression option
           Some (mk_apps cons fields_values).e
   in
   match e_opt with None -> None | Some e -> Some { e; ty = pat.ty }
+
+type trait_decl_method_decl_id = { is_provided : bool; id : fun_decl_id }
+
+let trait_decl_get_method (trait_decl : trait_decl) (method_name : string) :
+    trait_decl_method_decl_id =
+  (* First look in the required methods *)
+  let method_id =
+    List.find_opt (fun (s, _) -> s = method_name) trait_decl.required_methods
+  in
+  match method_id with
+  | Some (_, id) -> { is_provided = false; id }
+  | None ->
+      (* Must be a provided method *)
+      let _, id =
+        List.find (fun (s, _) -> s = method_name) trait_decl.provided_methods
+      in
+      { is_provided = true; id = Option.get id }
+
+let trait_decl_is_empty (trait_decl : trait_decl) : bool =
+  let {
+    def_id = _;
+    name = _;
+    generics = _;
+    preds = _;
+    parent_clauses;
+    consts;
+    types;
+    required_methods;
+    provided_methods;
+  } =
+    trait_decl
+  in
+  parent_clauses = [] && consts = [] && types = [] && required_methods = []
+  && provided_methods = []
+
+let trait_impl_is_empty (trait_impl : trait_impl) : bool =
+  let {
+    def_id = _;
+    name = _;
+    impl_trait = _;
+    generics = _;
+    preds = _;
+    parent_trait_refs;
+    consts;
+    types;
+    required_methods;
+    provided_methods;
+  } =
+    trait_impl
+  in
+  parent_trait_refs = [] && consts = [] && types = [] && required_methods = []
+  && provided_methods = []