Levity-polymorphic type synonym doesn't work

[goldfirere]

{-# LANGUAGE DeriveDataTypeable, TypeFamilies, TemplateHaskell, DataKinds,
             PolyKinds, GADTs, RankNTypes, MultiParamTypeClasses,
             FlexibleInstances, UndecidableInstances, CPP,
             FunctionalDependencies, StandaloneDeriving,
             TypeOperators, ScopedTypeVariables, NoMonomorphismRestriction,
             MonadComprehensions, DeriveGeneric, FlexibleContexts,
             GeneralizedNewtypeDeriving, ConstraintKinds,
             LambdaCase, ViewPatterns, -- AllowAmbiguousTypes,
             DefaultSignatures, -- ImpredicativeTypes,
             ImplicitParams, MagicHash, UnboxedTuples, RoleAnnotations,
             ExtendedDefaultRules, PatternSynonyms, EmptyCase,
             BangPatterns, InstanceSigs, NamedWildCards,
             DeriveFunctor, Arrows, PartialTypeSignatures
--             , TypeInType
  #-}

module Scratch where

import GHC.Exts

type Tuple (a :: TYPE v1) (b :: TYPE v2) = (# a, b #)

It seems the args to Tuple get defaulted to *.