Re: [Haskell-cafe] Undecideable instances for one instance?

Hello Christophe, Wednesday, June 7, 2006, 12:27:22 PM, you wrote:

global instance of a typeclass (so there is no overlapping), GHC will still complain about overlapping. Is there any reason this is so or is

GHC compains here about undecidability, not overlapping :)

-- Illegal instance declaration for `Locatable a' -- (There must be at least one non-type-variable in the instance head -- Use -fallow-undecidable-instances to permit this) -- In the instance declaration for `Locatable a'

Christophe(vincenz)

-- Best regards, Bulat mailto:Bulat.Ziganshin@gmail.com