John Tromp wrote:
> >>instance (Bar a) => Foo a
> I have tried to write code myself like in the last line,
> stating that any instance of one class should also be
> an instance of another class. But Hugs would complain about
> it.
You're right. Hugs needs to be told that the code is in an extend
[EMAIL PROTECTED] wrote:
There appears to be a problem with GHC's handling of multi-parameter
constraints with functional dependencies in the context of rank-2
types. The problem is not present in Hugs.
Let us first consider a simple example:
module Test where
class Foo a
class Bar a
data Obj =
That is indeed bizarre. I'll look into it.
Simon
| -Original Message-
| From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
On Behalf Of
| [EMAIL PROTECTED]
| Sent: 13 January 2004 05:51
| To: [EMAIL PROTECTED]
| Subject: GHC, functional dependency, rank-2 type
|
|
| There appears
There appears to be a problem with GHC's handling of multi-parameter
constraints with functional dependencies in the context of rank-2
types. The problem is not present in Hugs.
Let us first consider a simple example:
> module Test where
> class Foo a
>
> class Bar a
>
> data Obj = Obj
>
> insta
