18 Jan
2016
18 Jan
'16
3:42 p.m.
On Mon, 18 Jan 2016, David Feuer wrote:
Actually, I currently get a much worse error message:
Prelude> fmap (+1) (1,2,3)
<interactive>:2:1: Non type-variable argument in the constraint: Functor ((,,) t t) (Use FlexibleContexts to permit this) When checking that ‘it’ has the inferred type it :: forall b t t1. (Functor ((,,) t t1), Num b, Num t, Num t1) => (t, t1, b)
That there is a *lousy* error message.
indeed
I understand that there are newcomers who struggle to understand the difference between tuples and lists; I don't think that's a good enough reason to omit a good and valid instance.
I would not qualify myself as a newcomer. For me these instances are a problem, not a help.