Decomposition of AppTy broken
This program (taken from lens
) wrongly fails in GHC's HEAD
{-# LANGUAGE UndecidableInstances #-}
import Control.Applicative
import Control.Category
import Prelude hiding ((.),id)
newtype FocusingPlus w k s a = FocusingPlus { unfocusingPlus :: k (s, w) a }
instance Functor (k (s, w)) => Functor (FocusingPlus w k s) where
fmap f (FocusingPlus as) = FocusingPlus (fmap f as)
instance Applicative (k (s, w)) => Applicative (FocusingPlus w k s) where
pure = FocusingPlus . pure
FocusingPlus kf <*> FocusingPlus ka = FocusingPlus (kf <*> ka)
Trac metadata
Trac field | Value |
---|---|
Version | 7.8.3 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | Compiler |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | |
Operating system | |
Architecture |