Re: [GHC] #8807: Variable constraints not handled properly in TH

26 Feb 2014

      #8807: Variable constraints not handled properly in TH
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        Reporter:  goldfire          |            Owner:  goldfire
            Type:  bug               |           Status:  new
        Priority:  normal            |        Milestone:  7.10.1
       Component:  Template Haskell  |          Version:  7.9
      Resolution:                    |         Keywords:
Operating System:  Unknown/Multiple  |     Architecture:  Unknown/Multiple
 Type of failure:  None/Unknown      |       Difficulty:  Unknown
       Test Case:                    |       Blocked By:
        Blocking:                    |  Related Tickets:
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Comment (by Richard Eisenberg ):

 In [changeset:"98b6756b09194352aa2ccfbb624992150a7a3520/ghc"]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="98b6756b09194352aa2ccfbb624992150a7a3520"
 Fix #8807.

 It turns out that the enhanced repPred function in DsMeta assumed
 that the head of any constraint would be a tycon. This assumption
 is false. Happily, the solution involved *deleting* code. I
 just removed repPred in favor of repTy, and added the HsEqTy case
 to repTy, where it should be anyway.
 }}}

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Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8807#comment:1
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