where
-- We can't call dsHsType on res_ty, and then do tcSplitTyConApp_maybe
-- because that causes a black hole, and for good reason. Building
-- the type means expanding type synonyms, and we can't do that
-- inside the "knot". So we have to work by steam.
where
-- We can't call dsHsType on res_ty, and then do tcSplitTyConApp_maybe
-- because that causes a black hole, and for good reason. Building
-- the type means expanding type synonyms, and we can't do that
-- inside the "knot". So we have to work by steam.