[GHC] #13046: TH Names can't be used in patterns

30 Dec 2016

      #13046: TH Names can't be used in patterns
-------------------------------------+-------------------------------------
           Reporter:  Artyom.Kazak   |             Owner:
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:
          Component:  Compiler       |           Version:  8.0.1
           Keywords:                 |  Operating System:  Unknown/Multiple
       Architecture:                 |   Type of failure:  GHC rejects
  Unknown/Multiple                   |  valid program
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
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 Here's an example where I try to use a `Name` (with double ticks) as a
 pattern:

 {{{#!hs
 {-# LANGUAGE TemplateHaskell #-}

 foo :: Name -> ()
 foo ''Int = ()
 }}}

 It fails with this error:

 {{{#!text
 test.hs:4:5-9: Parse error in pattern: ''Int
 }}}

 Seems like a bug to me (if we can compare `Name`s, why can't we pattern-
 match on them?).

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Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13046
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