Fine grained STRICT pragmas

Currently STRICT pragmas can only be applied at a module scale. It'd be more useful to have more fine-grained STRICT pragmas that can be applied to functions in a module. For example, here's function from GHC:

tidyType :: TidyEnv -> Type -> Type
tidyType _   (LitTy n)             = LitTy n
tidyType env (TyVarTy tv)          = TyVarTy (tidyTyCoVarOcc env tv)
tidyType env (TyConApp tycon tys)  = let args = tidyTypes env tys
                                     in args `seqList` TyConApp tycon args
tidyType env (AppTy fun arg)       = (AppTy $! (tidyType env fun)) $! (tidyType env arg)
tidyType env ty@(FunTy _ arg res)  = let { !arg' = tidyType env arg
                                         ; !res' = tidyType env res }
                                     in ty { ft_arg = arg', ft_res = res' }
tidyType env (ty@(ForAllTy{}))     = mkForAllTys' (zip tvs' vis) $! tidyType env' body_ty
  where
    (tvs, vis, body_ty) = splitForAllTys' ty
    (env', tvs') = tidyVarBndrs env tvs
tidyType env (CastTy ty co)       = (CastTy $! tidyType env ty) $! (tidyCo env co)
tidyType env (CoercionTy co)      = CoercionTy $! (tidyCo env co)

Every let binding has a bang, and function applications are done strictly ($!). If we supported {-# STRICT tidyType #-} this would be much simpler: (NOTE: I'm not sure if -XStrict turns normal applications into strict applications, below I'm assuming it does)

{-# STRICT tidyType #-}

tidyType :: TidyEnv -> Type -> Type
tidyType _   (LitTy n)             = LitTy n
tidyType env (TyVarTy tv)          = TyVarTy (tidyTyCoVarOcc env tv)
tidyType env (TyConApp tycon tys)  = TyConApp tycon (seqListId (tidyTypes env tys))
tidyType env (AppTy fun arg)       = AppTy (tidyType env fun) (tidyType env arg)
tidyType env ty@(FunTy _ arg res)  = ty { ft_arg = tidyType env arg, ft_res = tidyType env res }
tidyType env (ty@(ForAllTy{}))     = mkForAllTys' (zip tvs' vis) (tidyType env' body_ty)
  where
    (~tvs, ~vis, ~body_ty) = splitForAllTys' ty
    (~env', ~tvs') = tidyVarBndrs env tvs
tidyType env (CastTy ty co)       = CastTy (tidyType env ty) (tidyCo env co)
tidyType env (CoercionTy co)      = CoercionTy (tidyCo env co)