[GHC] #14266: AllowAmbiguousTypes doesn't play well with default class methods

[GHC]

#14266: AllowAmbiguousTypes doesn't play well with default class methods
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        Reporter:  chris-martin      |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.0.2
      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):

 Replying to [comment:7 chris-martin]:
 > I suppose that's something I'm not clear on. What is the language
 designers' attitude toward the `TypeApplications` extension? Is it there
 to be an imperfect workaround for the occasional odd situation, or is
 Haskell now intended to be a language where programming with ambiguous
 types and explicit type applications is normal and fully supported? It
 still //feels// a bit like I'm abusing the type system.

 I can only speak as a single GHC developer, but I would certainly hope
 that `TypeApplications` is just as "fully supported" as anything else you
 can do in GHC (and I suspect I'm not alone in this regard). The somewhat
 unfortunate reality is that this extension is fairly new in the Haskell
 ecosystem, and as a result, there's been less time to discover odd
 interactions between it and other language extensions (of which this bug
 is an example). With the help of intrepid programmers like yourself, I
 think we'll find a way to stamp out these oddities, and hopefully make
 `TypeApplications` feel less like "abusing" the type system.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14266#comment:8>
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