text: -- {-# OPTIONS -v tc.polarity:15 -v tc.inj:40 #-}
  module Issue168b where
  
  data Nat : Set where
    zero : Nat
    suc  : Nat → Nat
  
  module Membership (A : Set) where
  
    id : Nat → Nat
    id zero     = zero
    id (suc xs) = suc (id xs)
  