Hi,
Take a look at the following program, making use of
derivable type classes.
module Bug where
import Data.Generics
class Foo a where
foo :: a - Int
foo{| Unit |}_ = 1
foo{| a :*: b |} _ = 2
foo{| a :+: b |} _ = 3
instance Foo [a]
GHC 6.2.2 produces the following error
] On Behalf Of Koen Claessen
| Sent: 16 November 2004 17:17
| To: [EMAIL PROTECTED]
| Subject: Derivable type classes bug?
|
| Hi,
|
| Take a look at the following program, making use of
| derivable type classes.
|
|
| module Bug where
|
| import Data.Generics
|
| class Foo a where
| foo :: a - Int
