fact: Axiom foldr_parametricity : forall `{Foldable t} `{Functor t} A B (f : A -> B -> B) (u : B) A' B' (g : A' -> B' -> B') (u' : B') (a : A -> A') (b : B -> B'), b u = u' -> (forall x y, b (f x y) = g (a x) (b y)) -> b \o @foldr t _ A B f u = @foldr t _ A' B' g u' \o fmap a.
imports: Hask.Ltac Hask.Data.Functor