[GHC] #12407: Template Haskell thinks an unboxed tuple name is illegal to splice in

18 Jul 2016

      #12407: Template Haskell thinks an unboxed tuple name is illegal to splice in
-------------------------------------+-------------------------------------
           Reporter:  RyanGlScott    |             Owner:
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:  8.0.2
          Component:  Template       |           Version:  8.0.1
  Haskell                            |
           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:
-------------------------------------+-------------------------------------
 {{{#!hs
 {-# LANGUAGE TemplateHaskell #-}
 {-# LANGUAGE UnboxedTuples #-}
 module Bug where

 import Language.Haskell.TH.Lib
 import Language.Haskell.TH.Syntax

 $(do let ubxTup = conT (unboxedTupleTypeName 2) `appT` conT ''Int
                                                 `appT` conT ''Int
      x <- newName "x"
      y <- newName "y"

      [d| f :: $(ubxTup) -> $(ubxTup)
          f $(conP (unboxedTupleDataName 2) [varP x, varP y])
              = $(conE (unboxedTupleDataName 2) `appE` varE x
                                                `appE` varE y)
       |])
 }}}

 {{{
 $ /opt/ghc/8.0.1/bin/ghc Bug.hs
 [1 of 1] Compiling Bug              ( Bug.hs, Bug.o )

 Bug.hs:8:3: error:
     Illegal type constructor or class name: ‘(#,#)’
     When splicing a TH declaration:
       f_0 :: GHC.Tuple.(#,#) GHC.Types.Int GHC.Types.Int ->
        GHC.Tuple.(#,#) GHC.Types.Int GHC.Types.Int
 }}}

 Patch coming soon.

--
Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12407
GHC http://www.haskell.org/ghc/
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