[commit: packages/base] master: Add fmapCoerce to Functor class. (3da4fd9)

[Ross Paterson]

On Wed, Sep 25, 2013 at 10:18:51PM +0200, Joachim Breitner wrote:
> given the recently intensified urge to make GHC a more community driven
> project, may I suggest to reduce the amount of off-list discussions? I
> find it very confusing if some discussions happen on list, some
> discussion on list with certain people explictily CC’ed, and some
> discusisons off-list, and some alternating between these. I believe we
> are all able to ignore discussions on the list that are not relevant for
> us, but on-list discussions are easily referenced and re-read later.

I agree with all that, and also share Johan's alarm at the sudden
appearance of coerce in this class.

On the substance, I don't think Functor is the right place for this,
as it's about lifting isomorphisms rather than functions, and type
constructors don't have to be functors to support that.