ruleRhsFreeVars (Rule { ru_fn = _, ru_bndrs = bndrs, ru_rhs = rhs })
  = fvVarSet $ filterFV isLocalVar $ addBndrs bndrs (expr_fvs rhs)
ruleRhsFreeVars (Rule { ru_fn = _, ru_bndrs = bndrs, ru_rhs = rhs })
  = fvVarSet $ filterFV isLocalVar $ addBndrs bndrs (expr_fvs rhs)
ruleRhsFreeVars (Rule { ru_fn = _, ru_bndrs = bndrs, ru_rhs = rhs })
  = fvVarSet $ filterFV isLocalVar $ addBndrs bndrs (expr_fvs rhs)