diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/type_check.ml | 22 |
1 files changed, 21 insertions, 1 deletions
diff --git a/src/type_check.ml b/src/type_check.ml index f11b955a..82bc92d8 100644 --- a/src/type_check.ml +++ b/src/type_check.ml @@ -439,6 +439,7 @@ module Env : sig val add_constraint : n_constraint -> t -> t val get_typ_var : kid -> t -> kind_aux val get_typ_var_loc : kid -> t -> Ast.l + val get_typ_var_loc_opt : kid -> t -> Ast.l option val get_typ_vars : t -> kind_aux KBindings.t val get_typ_var_locs : t -> Ast.l KBindings.t val shadows : kid -> t -> int @@ -536,6 +537,11 @@ end = struct let allow_unknowns env = env.allow_unknowns let set_allow_unknowns b env = { env with allow_unknowns = b } + let get_typ_var_loc_opt kid env = + match KBindings.find_opt kid env.typ_vars with + | Some (l, _) -> Some l + | None -> None + let get_typ_var kid env = try snd (KBindings.find kid env.typ_vars) with | Not_found -> typ_error env (kid_loc kid) ("No type variable " ^ string_of_kid kid) @@ -1404,12 +1410,26 @@ let bind_numeric l typ env = | None -> typ_error env l ("Expected " ^ string_of_typ typ ^ " to be numeric") let rec check_shadow_leaks l inner_env outer_env typ = + typ_debug (lazy ("Shadow leaks: " ^ string_of_typ typ)); let vars = tyvars_of_typ typ in List.iter (fun var -> if Env.shadows var inner_env > Env.shadows var outer_env then typ_error outer_env l ("Type variable " ^ string_of_kid var ^ " would leak into a scope where it is shadowed") - else ()) + else + match Env.get_typ_var_loc_opt var outer_env with + | Some _ -> () + | None -> + match Env.get_typ_var_loc_opt var inner_env with + | Some leak_l -> + typ_raise outer_env l + (Err_because + (Err_other ("The type variable " ^ string_of_kid var + ^ " would leak into an outer scope.\n\nTry adding a type annotation to this expression."), + leak_l, + Err_other ("Type variable " ^ string_of_kid var ^ " was introduced here"))) + | None -> Reporting.unreachable l __POS__ "Found a type with an unknown type variable" + ) (KidSet.elements vars); typ |