message: Fix SetDiscriminant for generators
diff: @@ -340,9 +340,8 @@ fn trans_stmt<'a, 'tcx: 'a>(
  let ptr = place.place_field(fx, mir::Field::new(discr_index));
  let to = layout
  .ty
  - .ty_adt_def()
  - .unwrap()
  .discriminant_for_variant(fx.tcx, *variant_index)
  + .unwrap()
  .val;
  let discr = CValue::const_val(fx, ptr.layout().ty, to as u64 as i64);
  ptr.write_cvalue(fx, discr);
  