[GHC] #11650: Documentation does not mention that default definitions for Alternative(some, many) can easily blow up

[GHC]

#11650: Documentation does not mention that default definitions for
Alternative(some, many) can easily blow up
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        Reporter:  bgamari           |                Owner:
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Documentation     |              Version:  7.10.3
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by RyanGlScott):

 We could also fix this issue by making the `Applicative` instance less
 strict:

 {{{#!hs
 instance Applicative U1 where
   U1 <*> _ = U1
 }}}

 I'm not sure which is the best approach. `Proxy` (which is isomorphic to
 `U1`) doesn't pattern-match on its arguments in ''any'' of its instances,
 which allows it to short-circuit in a lot of possibly diverging
 computations. Then again, `Proxy` doesn't have an
 `Alternative`/`MonadPlus` instance for some reason...

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11650#comment:5>
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