notElemTvSubst :: CoVar -> TvSubst -> Bool
notElemTvSubst v (TvSubst _ tenv) = not (v `elemVarEnv` tenv)
notElemTvSubst :: CoVar -> TvSubst -> Bool
notElemTvSubst v (TvSubst _ tenv) = not (v `elemVarEnv` tenv)
notElemTvSubst v (TvSubst _ tenv) = not (v `elemVarEnv` tenv)