[Haskell-cafe] Re: Small displeasure with associated type synonyms

[Tom Schrijvers]

> Am I correct in thinking this would have worked if it were an
> associated type instead of an associated type synonym?
>
> ie,
>
> class C a where
>    data T a
>    val :: T a

Yes, you are. Associate data type constructors (as well as ordinary 
algebraic data constructors) are injective. So we have:

 	forall a b . T a = T b <=> a = b

Cheers,

Tom

--
Tom Schrijvers

Department of Computer Science
K.U. Leuven
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tel: +32 16 327544
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