fmapCoerce / changes in 7.8

David Luposchainsky dluposchainsky at
Thu Sep 26 07:59:59 UTC 2013

I'm also sceptical about this, regardless of whether it sounds like a
good idea now. Adding a function to a typeclass is trivial, removing it
later far from it (see fail, some, many). On the other hand, are there
reasons not to create

> class Functor f => FunctorC f where
>     fmapC :: Coercible a b => f a -> f b



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