[GHC] #8346: Rank 1 type signature still requires RankNTypes

[GHC]

#8346: Rank 1 type signature still requires RankNTypes
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        Reporter:  tinctorius                 |            Owner:
            Type:  bug                        |           Status:  new
        Priority:  normal                     |        Milestone:
       Component:  Compiler                   |          Version:  7.6.3
      Resolution:                             |         Keywords:
Operating System:  Unknown/Multiple           |     Architecture:
 Type of failure:  GHC rejects valid program  |  Unknown/Multiple
       Test Case:                             |       Difficulty:  Unknown
        Blocking:                             |       Blocked By:
                                              |  Related Tickets:  #2605
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Comment (by simonpj):

 I know it's technically not right but I'm disinclined to do much about it
 (myself anyway).  In fact I rather regret having `Rank2Types` as well as
 `RankNTypes`.  (I think that was originally because Hugs had the former
 but not the latter.  I'd rather have just a flag to say "all the foralls
 at the top, like Haskell 98" and "foralls anywhere".  Having lots of flags
 to enforce fine distinctions doesn't seem all that useful to me.

 If anyone wants to make a patch to more faithfully implement the current
 flags, by all means do so. I remember that it was tiresomely fiddly, which
 is why I compromised on the current behaviour.

 Simon

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8346#comment:2>
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