Data.Lazy.List is too strict

[natefaubion]

a :: List Number
a = Cons 1 $ defer \_ -> ((+) 1) <$> a

> take 5 a

RangeError: Maximum call stack size exceeded

Whereas:

map :: forall a b. (a -> b) -> List a -> List b
map f (Cons x thunk) = Cons (f x) $ defer \_ -> map f $ force thunk
map f Nil = Nil

a' :: List Number
a' = Cons 1 $ defer \_ -> map ((+) 1) a'

> take 5 a'

List(1, 2, 3, 4, 5)

[paf31]

Looks like the dodgy implementation of <$> is at fault here.