[GHC] #12132: Type representations missing for promoted boxed tuples

29 May 2016


      #12132: Type representations missing for promoted boxed tuples
-------------------------------------+-------------------------------------
           Reporter:  bgamari        |             Owner:  bgamari
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:  8.0.2
          Component:  Compiler       |           Version:  8.0.1
           Keywords:                 |  Operating System:  Unknown/Multiple
       Architecture:                 |   Type of failure:  None/Unknown
  Unknown/Multiple                   |
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
-------------------------------------+-------------------------------------
 This is a continuation of #11120. It seems there is something odd
 happening with type representations for boxed tuples,
 {{{
 $ inplace/bin/ghc-stage2 --interactive
 GHCi, version 8.1.20160528: http://www.haskell.org/ghc/  :? for help
 Prelude> :set -XDataKinds
 Prelude> :m + Data.Typeable Data.Proxy
 Prelude Data.Typeable Data.Proxy> typeOf (Proxy :: Proxy (Int,Int))
 Proxy * (Int,Int)
 Prelude Data.Typeable Data.Proxy> typeOf (Proxy :: Proxy '(Int,Int))
 GHC error in desugarer lookup in Ghci2:
   Can't find interface-file declaration for variable $tc'(,)
     Probable cause: bug in .hi-boot file, or inconsistent .hi file
     Use -ddump-if-trace to get an idea of which file caused the error
 ghc-stage2: panic! (the 'impossible' happened)
   (GHC version 8.1.20160528 for x86_64-unknown-linux):
         initDs IOEnv failure

 Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug

 Prelude Data.Typeable Data.Proxy>
 }}}
 This is odd since the `$tc'(,)` binding is present in the interface file
 for `GHC.Tuple`,
 {{{
 $ inplace/bin/ghc-stage2 --show-iface libraries/ghc-prim/dist-
 install/build/GHC/Tuple.dyn_hi |less
 ...
 14e44400752f4580e52ed2a760b9633f
   $tc'(,) :: TyCon
   {- HasNoCafRefs, Strictness: m,
      Unfolding: (TyCon
                    14407099369839560749##
                    10712746223293009168##
                    $trModule
                    $tc'(,)1) -}
 543be63d698612591d2e75b0b60ad643
   $tc'(,)1 :: TrName
   {- HasNoCafRefs, Strictness: m1, Unfolding: (TrNameS "'(,)"#) -}
 469b4ffe716da12a5be1f5ab03864791
   $tc'(,,) :: TyCon
   {- HasNoCafRefs, Strictness: m,
      Unfolding: (TyCon
                    3540448346642256323##
                    9150387332266490903##
                    $trModule
                    $tc'(,,)1) -}
 ...
 }}}

--
Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12132
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