1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
|
{-# LANGUAGE
ScopedTypeVariables
, DataKinds
, GADTs
, RankNTypes
, TypeOperators
, PolyKinds -- Comment out PolyKinds and the bug goes away.
#-}
{-# OPTIONS_GHC -O #-}
-- The bug is in SimplUtils.abstractFloats, so we need -O to trigger it
module KeyValue where
data AccValidation err a = AccFailure err | AccSuccess a
data KeyValueError = MissingValue
type WithKeyValueError = AccValidation [KeyValueError]
missing :: forall f rs. RecApplicative rs => Rec (WithKeyValueError :. f) rs
missing = rpure missingField
where
missingField :: forall x. (WithKeyValueError :. f) x
missingField = Compose $ AccFailure [MissingValue]
data Rec :: (u -> *) -> [u] -> * where
RNil :: Rec f '[]
(:&) :: !(f r) -> !(Rec f rs) -> Rec f (r ': rs)
newtype Compose (f :: l -> *) (g :: k -> l) (x :: k)
= Compose { getCompose :: f (g x) }
type (:.) f g = Compose f g
class RecApplicative rs where
rpure
:: (forall x. f x)
-> Rec f rs
|
