TypeScript Issue with `yield*` and Generator Returning `never`

declare function returnNever(): never;
declare function yieldNever(): Generator<never>;

const wrappedInEffect = Effect.gen(function* () {
  const a = null as number | null;
  // doesn't narrow
  if (a == null) {
    yield* yieldNever();
  }
  // does narrow
  if (a == null) {
    returnNever();
  }
  return a + 1;
});

declare function returnNever(): never;
declare function yieldNever(): Generator<never>;

const wrappedInEffect = Effect.gen(function* () {
  const a = null as number | null;
  // doesn't narrow
  if (a == null) {
    yield* yieldNever();
  }
  // does narrow
  if (a == null) {
    returnNever();
  }
  return a + 1;
});