diff options
Diffstat (limited to 'src/monomorphise.ml')
| -rw-r--r-- | src/monomorphise.ml | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/src/monomorphise.ml b/src/monomorphise.ml index fc6d5bfe..b7c6142b 100644 --- a/src/monomorphise.ml +++ b/src/monomorphise.ml @@ -392,7 +392,16 @@ let refine_constructor refinements l env id args = match Type_check.destruct_exist (Type_check.Env.expand_synonyms env constr_ty) with | None -> None | Some (kopts,nc,constr_ty) -> - let bindings = Type_check.unify l env (tyvars_of_typ constr_ty) constr_ty arg_ty in + (* Remove existentials in argument types to prevent unification failures *) + let unwrap (Typ_aux (t,_) as typ) = match t with + | Typ_exist (_,_,typ) -> typ + | _ -> typ + in + let arg_ty = match arg_ty with + | Typ_aux (Typ_tup ts,annot) -> Typ_aux (Typ_tup (List.map unwrap ts),annot) + | _ -> arg_ty + in + let bindings = Type_check.unify l env (tyvars_of_typ constr_ty) constr_ty arg_ty in let find_kopt kopt = try Some (KBindings.find (kopt_kid kopt) bindings) with Not_found -> None in let bindings = List.map find_kopt kopts in let matches_refinement (mapping,_,_) = |