Add another flow-typing case for E_internal_plet

Copied from a corresponding case for E_block, so that this flow typing
still gets picked up after E_block has been rewritten away.

1 files changed, 7 insertions, 0 deletions

diff --git a/src/type_check.ml b/src/type_check.ml
index ddd16eef..11d5e6a0 100644
--- a/src/type_check.ml
+++ b/src/type_check.ml
@@ -2466,6 +2466,13 @@ let rec check_exp env (E_aux (exp_aux, (l, ())) as exp : unit exp) (Typ_aux (typ
                Env.add_constraint nc env
             | None -> env
           end
+       | E_aux (E_if (cond, e_t, e_e), _) ->
+          begin
+            match unaux_exp (fst (uncast_exp e_t)) with
+            | E_throw _ | E_block [E_aux (E_throw _, _)] ->
+               add_opt_constraint (option_map nc_not (assert_constraint env false cond)) env
+            | _ -> env
+          end
        | _ -> env in
      let checked_body = crule check_exp env body typ in
      annot_exp (E_internal_plet (tpat, bind_exp, checked_body)) typ