[GHC] #11824: GHC error in desugarer lookup

[GHC]

#11824: GHC error in desugarer lookup
-------------------------------------+-------------------------------------
        Reporter:  darchon           |                Owner:
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.0.1
       Component:  Compiler          |              Version:  8.0.1-rc3
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  crash                              |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
-------------------------------------+-------------------------------------

Comment (by darchon):

 I've reduced the test case even further and it has no more dependencies
 outside of base.
 The new steps to reproduce are:

 * git clone ​https://github.com/christiaanb/IfaceError.git
 * cd IfaceError
 * ghci CLaSH/Core/Type.hs

 The output of the ddump-if-trace is now much shorter:

 {{{
 ghci CLaSH/Core/Type.hs
 GHCi, version 8.0.0.20160411: http://www.haskell.org/ghc/  :? for help
 [1 of 4] Compiling Unbound.Generics.LocallyNameless (
 Unbound/Generics/LocallyNameless.hs, interpreted )
 [2 of 4] Compiling CLaSH.Core.Type[boot] ( CLaSH/Core/Type.hs-boot,
 interpreted )
 [3 of 4] Compiling CLaSH.Core.TyCon ( CLaSH/Core/TyCon.hs, interpreted )
 loadHiBootInterface CLaSH.Core.TyCon
 Considering whether to load Prelude
 Considering whether to load GHC.Generics
 Considering whether to load Unbound.Generics.LocallyNameless
 Considering whether to load CLaSH.Core.Type {- SOURCE -}
 updating EPS_
 Considering whether to load GHC.Base {- SYSTEM -}
 Considering whether to load GHC.Float {- SYSTEM -}
 newGlobalBinder CLaSH.Core.TyCon AlgTyConRhs
 CLaSH/Core/TyCon.hs:(13,1)-(15,26)
                 AlgTyConRhs
 newGlobalBinder CLaSH.Core.TyCon NewTyCon CLaSH/Core/TyCon.hs:14:5-19
                 NewTyCon
 Considering whether to load GHC.Generics {- SYSTEM -}
 Considering whether to load Unbound.Generics.LocallyNameless {- SYSTEM -}
 Considering whether to load CLaSH.Core.Type {- SYSTEM -}
 newGlobalBinder CLaSH.Core.TyCon $tc'NewTyCon <no location info>
                 $tc'NewTyCon
 newGlobalBinder CLaSH.Core.TyCon $WNewTyCon CLaSH/Core/TyCon.hs:14:5-19
                 $WNewTyCon
 newGlobalBinder CLaSH.Core.TyCon NewTyCon CLaSH/Core/TyCon.hs:14:5-19
                 NewTyCon
 buildDataCon 1 NewTyCon
 buildDataCon 2 NewTyCon
 newGlobalBinder CLaSH.Core.TyCon $tcAlgTyConRhs <no location info>
                 $tcAlgTyConRhs
 newGlobalBinder CLaSH.Core.TyCon $fGenericAlgTyConRhs
 CLaSH/Core/TyCon.hs:15:13-19
                 $fGenericAlgTyConRhs
 newGlobalBinder CLaSH.Core.TyCon $fAlphaAlgTyConRhs
 CLaSH/Core/TyCon.hs:15:21-25
                 $fAlphaAlgTyConRhs
 newGlobalBinder CLaSH.Core.TyCon Rep_AlgTyConRhs
 CLaSH/Core/TyCon.hs:(13,1)-(15,26)
                 Rep_AlgTyConRhs
 newGlobalBinder CLaSH.Core.TyCon $trModule CLaSH/Core/TyCon.hs:1:1
                 $trModule
 Considering whether to load GHC.Types {- SYSTEM -}
 checkWiredInTyCon Double
 CLaSH.Core.TyCon
 Considering whether to load GHC.Types {- SYSTEM -}
 Need decl for $tcType
 Considering whether to load CLaSH.Core.Type {- SYSTEM -}
 GHC error in desugarer lookup in CLaSH.Core.TyCon:
   Can't find interface-file declaration for variable $tcType
     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: panic! (the 'impossible' happened)
   (GHC version 8.0.0.20160411 for x86_64-unknown-linux):
         initDs IOEnv failure

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

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11824#comment:2>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler