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Re: [Haskell-cafe] lawless instances of Functor

Subject: Re: [Haskell-cafe] lawless instances of Functor
From: Jochem Berndsen
Date: Mon, 04 Jan 2010 23:53:16 +0100
Steffen Schuldenzucker wrote:
> data Foo a = Foo a
> 
> instance Functor Foo where
>     fmap f (Foo x) = Foo . f . f $ x

I think this doesn't typecheck.

Cheers, Jochem

-- 
Jochem Berndsen | [email protected] | [email protected]çåçé.com
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