Skip to content

feat(effects): thread parametric Throws[E] type argument (Refs #59) #204

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
hyperpolymath merged 1 commit into from
May 18, 2026
Merged

feat(effects): thread parametric Throws[E] type argument (Refs #59) #204

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
17 changes: 16 additions & 1 deletion lib/typecheck.ml
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -452,7 +452,22 @@ and lower_effect_expr (ctx : context) (ee : effect_expr) : eff =
in
match ee with
| EffVar { name; _ } -> resolve name
| EffCon ({ name; _ }, _args) -> resolve name
| EffCon ({ name; _ }, args) ->
(* Parametric effect, e.g. `Throws[MyErr]` (issue #59). Effect
*tracking* only: carry the type argument by mangling it into the
singleton name, so `Throws[A]`, `Throws[B]` and bare `Throws` are
distinct under the string-equality unification of `eff` — without
growing the `eff` ADT (which would ripple across every effect
operation). The base name is still validated via `resolve`. *)
(match resolve name with
| ESingleton base when args <> [] ->
let arg_str =
args
|> List.map (fun (TyArg te) -> ty_to_string (lower_type_expr ctx te))
|> String.concat ", "
in
ESingleton (base ^ "[" ^ arg_str ^ "]")
| other -> other)
| EffUnion (e1, e2) ->
EUnion [lower_effect_expr ctx e1; lower_effect_expr ctx e2]

Expand Down
Loading