Re: [GHC] #15592: Type families without CUSKs cannot be given visible kind variable binders

4 Oct 2018

      #15592: Type families without CUSKs cannot be given visible kind variable binders
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        Reporter:  RyanGlScott       |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.8.1
       Component:  Compiler          |              Version:  8.4.3
      Resolution:                    |             Keywords:
                                     |  TypeApplications, TypeFamilies,
                                     |  CUSKs
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:  14880             |             Blocking:
 Related Tickets:  #15591            |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by Simon Peyton Jones <simonpj@…>):

 In [changeset:"2f09753f96207c12efd43090f5de55b05aef35d3/ghc"
 2f09753f/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="2f09753f96207c12efd43090f5de55b05aef35d3"
 Distinguish Inferred from Specified tyvars

 In a declared type we need to distinguish between Inferred
 and Specified type variables. This was exposed by Trac #15592.

 See Note [Work out final tyConBinders] in TcTyClsDecls.

 I had to change the definition of HasField in GHC.Records to
    class HasField x r a | x r -> a where
 so as to have an /inferred/ kind argument rather than a
 specfied one.  So
    HasField :: forall {k}. k -> * -> * -> Constraint
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15592#comment:13>
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