[GHC] #14200: Deprecate WrappedMonad

[GHC]

#14200: Deprecate WrappedMonad
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        Reporter:  siddhanathan      |                Owner:  (none)
            Type:  task              |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  libraries/base    |              Version:  8.2.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #13876            |  Differential Rev(s):
       Wiki Page:                    |
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Changes (by RyanGlScott):

 * cc: hvr, ekmett, core-libraries-committee@… (added)
 * related:   => #13876


Comment:

 I'm inclined to agree here. At one point in time, where `return` was a
 canonical class method of `Monad`, it was commonplace to define
 `Applicative` and `Functor` methods entirely in terms of `Monad` methods.
 But now `return = pure`, and there are
 [https://ghc.haskell.org/trac/ghc/wiki/Proposal/MonadOfNoReturn plans] to
 eventually remove `return` as a class method of `Monad` entirely. When
 this happens, `WrappedMonad` won't be nearly as useful as it once was,
 since one won't be able to define `Applicative(pure)` from an arbitrary
 `Monad` instance anymore (see also #13876). This makes the utility of a
 `WrappedMonad` newtype dubious.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14200#comment:1>
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