module Issue279 where data ⊥ : Set where data ⊤ : Set where tt : ⊤ module M (A : Set) where data P : ⊤ → Set where tt : A → P tt open M ⊥ using (tt) good : ⊥ → M.P ⊥ tt good = tt bad : M.P ⊤ tt bad = tt tt