[Haskell-cafe] Why distinct tyvars in instance declarations?
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.
More information about the Haskell-Cafe