Re: [GHC] #9433: Partially applied type family allowed but unusable

25 Aug 2014

      #9433: Partially applied type family allowed but unusable
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              Reporter:  hesselink   |            Owner:
                  Type:  bug         |           Status:  new
              Priority:  normal      |        Milestone:
             Component:  Compiler    |          Version:  7.9
  (Type checker)                     |         Keywords:
            Resolution:              |     Architecture:  Unknown/Multiple
      Operating System:              |       Difficulty:  Unknown
  Unknown/Multiple                   |       Blocked By:
       Type of failure:  GHC         |  Related Tickets:
  accepts invalid program            |
             Test Case:              |
              Blocking:              |
Differential Revisions:              |
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Comment (by Simon Peyton Jones ):

 In [changeset:"ee4501bbad6480509e8a60b5ff89c0b0b228b66d/ghc"]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="ee4501bbad6480509e8a60b5ff89c0b0b228b66d"
 Check for un-saturated type family applications

 This patch corrects an egregious error introduced by:

   commit 022f8750edf6f413fba31293435dcc62600eab77
   Author: Simon Peyton Jones 
   Date:   Thu May 15 16:07:04 2014 +0100

     Refactoring around TyCon.isSynTyCon

     * Document isSynTyCon better
     * Add isTypeSyonymTyCon for regular H98 type synonyms
     * Use isTypeSynonymTyCon rather than isSynTyCon where
       the former is really intended

 At this particular spot in TcValidity we really do mean
 isSynTyCon and not isTypeSynonymTyCon.

 Fixes Trac #9433
 }}}

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Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9433#comment:2
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