[dc] -> do
let arg_tys = DataCon.dataConRepArgTys dc
-- TODO: CoreSubst docs say each Subs can be applied only once. Is this a
-- violation? Or does it only mean not to apply it again to the same
-- subject?
let real_arg_tys = map (CoreSubst.substTy subst) arg_tys
[dc] -> do
let arg_tys = DataCon.dataConRepArgTys dc
-- TODO: CoreSubst docs say each Subs can be applied only once. Is this a
-- violation? Or does it only mean not to apply it again to the same
-- subject?
let real_arg_tys = map (CoreSubst.substTy subst) arg_tys