Re: [GHC] #10516: PolyKinds results in incorrect reporting of type synonym parameter count

18 Jun 2015

      #10516: PolyKinds results in incorrect reporting of type synonym parameter count
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        Reporter:  benjamin.hodgson  |                   Owner:
            Type:  bug               |                  Status:  new
        Priority:  normal            |               Milestone:
       Component:  Compiler          |                 Version:  7.10.1
      Resolution:                    |                Keywords:
Operating System:  MacOS X           |            Architecture:  x86_64
 Type of failure:  None/Unknown      |  (amd64)
      Blocked By:                    |               Test Case:
 Related Tickets:                    |                Blocking:
                                     |  Differential Revisions:
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Comment (by Simon Peyton Jones ):

 In [changeset:"5879d5aab929e9959d48e03dad456b824160b3bf/ghc"]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="5879d5aab929e9959d48e03dad456b824160b3bf"
 Report arity errors correctly despite kinds

 Trac #10516 pointed out that when reporting arity errors
 (like "T needs 2 arguments but has been given 1"), we should
 not count kind arguments, since they are implicit.  If we
 include kind args in the count, we get very confusing error
 messages indeed.

 I did a little bit of refactoring which make some
 error messages wobble around.  But the payload of
 this fix is in TcValidity.tyConArityErr
 }}}

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Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10516#comment:4
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