[Haskell-cafe] Why distinct tyvars in instance declarations?

Josh Hoyt joshhoyt at gmail.com
Mon Jun 27 14:00:09 EDT 2005

On 6/27/05, robert dockins <robdockins at fastmail.fm> wrote:
> I think that you are mistaken.  The OP listed:
>  > class Foo a
>  > instance Foo (Either b b)
> Without further information, Haskell compilers will assume that the
> type(s) in a class declaration has/have kind * (Report section 4.6).
> Either b b does have kind *, so that's not the problem.


> class Foo a
> instance Foo (Either b c)

*is* accepted, so this is not a kind error.

Josh Hoyt

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