patch applied (packages/base): move Monad and MonadFix instances for Either from mtl (proposal #4159)

[Ross Paterson]

Thu Jul 29 05:24:49 PDT 2010  Ross Paterson <ross at soi.city.ac.uk>
  * move Monad and MonadFix instances for Either from mtl (proposal #4159)
  
  The Monad and MonadFix instances for Either (formerly in the mtl
  package) are moved to Control.Monad.Instances and Control.Monad.Fix
  respectively.  The Monad instance is still an orphan, to retain Haskell
  98 compatibility, but the MonadFix instance is together with its class.
  The Error constraint is removed from both instances, and the default
  definition of fail is used.

    M ./Control/Monad/Fix.hs +7
    M ./Control/Monad/Instances.hs +5

View patch online:
http://darcs.haskell.org/cgi-bin/darcsweb.cgi?r=packages/base;a=darcs_commitdiff;h=20100729122449-b47d3-c824e5c87b2b7a6cf74541038152fdff6b8cb91c.gz