[GHC] #14733: Won't use (forall xx. f xx) with -XQuantifiedConstraints

[GHC]

#14733: Won't use (forall xx. f xx) with -XQuantifiedConstraints
-------------------------------------+-------------------------------------
        Reporter:  Iceland_jack      |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.5
      Resolution:                    |             Keywords:
                                     |  QuantifiedConstraints, wipT2893
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
-------------------------------------+-------------------------------------

Comment (by Iceland_jack):

 Replying to [comment:3 simonpj]:
 > Currently this is by-design, but we could change the design.

 I'm +1 on change but that's easy to say, is it a task that takes deep GHC
 knowhow?

 > How bad is the restriction?

 Hard to say. If it's a matter of encoding them class aliases then it is a
 huge improvement over the current situation, otherwise may rule out a lot
 of fun examples.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14733#comment:7>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler