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GHC error in desugarer lookup

    • Closed Issue created by darchon @trac-darchon

    In GHC8-rc3, I'm getting:

        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

    To reproduce (requires stack):

    The -ddump-if-trace of CLaSH.Core.TyCon can be found here: https://gist.github.com/christiaanb/1cd84e9941f6614321719e298cc12af0

    I'm terribly sorry that the current instructions for reproducing the bug are to build my project and all its dependencies. I'm having a lot of trouble reducing the bug to a sensible/small test case, so any hints as to what might be the cause of this bug would be helpful.

    Trac metadata
    Trac field Value
    Version 8.0.1-rc3
    Type Bug
    TypeOfFailure OtherFailure
    Priority normal
    Resolution Unresolved
    Component Compiler
    Test case
    Differential revisions
    BlockedBy
    Related
    Blocking
    CC
    Operating system
    Architecture
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    Activity

    • darchon changed milestone to %8.0.1

      changed milestone to %8.0.1

    • darchon changed weight to 5

      changed weight to 5

    • darchon added Tbug Trac import labels

      added Tbug Trac import labels

    • darchon
      darchon @trac-darchon ·
      Author

      I've managed to reduce the test case a bit, relying only on the unbound-generics package (and its transitive dependencies):

      I will try to reduce it further to get rid of the unbound-generics dependency.

    • darchon
      darchon @trac-darchon ·
      Author

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

      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
    • darchon
      darchon @trac-darchon ·
      Author

      I've managed to reduce it even furter.

      I now have:

      Unbound/Generics/LocallyNameless.hs:

      module Unbound.Generics.LocallyNameless where

import Data.Typeable (Typeable)

data Name a = Name

class Alpha a where
  isTerm :: a -> Bool

instance Typeable a => Alpha (Name a) where
  isTerm _ = False

      CLaSH/Core/Type.hs:

      module CLaSH.Core.Type where

import Unbound.Generics.LocallyNameless (Alpha (..),Name)
import CLaSH.Core.TyCon

data Type = VarTy

type TyName = Name Type

instance Alpha Type where
  isTerm VarTy = False

      CLaSH/Core/Type.hs-boot

      module CLaSH.Core.Type where

import Unbound.Generics.LocallyNameless (Name)

data Type

type TyName = Name Type

      CLaSH/Core/TyCon.hs

      {-# OPTIONS_GHC -ddump-if-trace #-}
module CLaSH.Core.TyCon where

import Unbound.Generics.LocallyNameless (Alpha (..))
import {-# SOURCE #-} CLaSH.Core.Type   (TyName)

data AlgTyConRhs
  = NewTyCon TyName

instance Alpha AlgTyConRhs where
  isTerm (NewTyCon nm) = isTerm nm

      And the output of -ddump-if-trace is:

      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 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:(7,1)-(8,19)
                AlgTyConRhs
newGlobalBinder CLaSH.Core.TyCon NewTyCon CLaSH/Core/TyCon.hs:8:5-19
                NewTyCon
Considering whether to load Unbound.Generics.LocallyNameless {- SYSTEM -}
Considering whether to load CLaSH.Core.Type {- SYSTEM -}
Considering whether to load Unbound.Generics.LocallyNameless {- SYSTEM -}
Considering whether to load Unbound.Generics.LocallyNameless {- SYSTEM -}
newGlobalBinder CLaSH.Core.TyCon $tc'NewTyCon <no location info>
                $tc'NewTyCon
newGlobalBinder CLaSH.Core.TyCon $WNewTyCon CLaSH/Core/TyCon.hs:8:5-19
                $WNewTyCon
newGlobalBinder CLaSH.Core.TyCon NewTyCon CLaSH/Core/TyCon.hs:8:5-19
                NewTyCon
buildDataCon 1 NewTyCon
buildDataCon 2 NewTyCon
newGlobalBinder CLaSH.Core.TyCon $tcAlgTyConRhs <no location info>
                $tcAlgTyConRhs
newGlobalBinder CLaSH.Core.TyCon $fAlphaAlgTyConRhs CLaSH/Core/TyCon.hs:10:10-26
                $fAlphaAlgTyConRhs
newGlobalBinder CLaSH.Core.TyCon $trModule CLaSH/Core/TyCon.hs:1:1
                $trModule
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

      It seems to be a combination of the Typeable constraint, and the .hs-boot file. Because when I remove the Typeable constraint from:

      instance Typeable a => Alpha (Name a) where
  isTerm _ = False

      in Unbound/Generics/LocallyNameless.hs everything compiles successfully.

    • darchon
      darchon @trac-darchon ·
      Author

      I wanted to report a separate (but perhaps related) error. When I change

      Unbound/Generics/LocallyNameless.hs to

      module Unbound.Generics.LocallyNameless where

import Data.Typeable (Typeable)

data Name a = Name

class Alpha a where
  isTerm :: a -> Bool

instance Alpha (Name a) where
  isTerm _ = False

      and CLaSH/Core/Type.hs to

      module CLaSH.Core.Type where

import Unbound.Generics.LocallyNameless (Alpha (..),Name)
import CLaSH.Core.TyCon

data Type = VarTy

type TyName = Name Type

instance Alpha Type where
  isTerm Foo = False

      I get:

      ~/devel/IfaceError(master *) $ ghci CLaSH/Core/Type.hs
GHCi, version 8.1.20160412: 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 )
[4 of 4] Compiling CLaSH.Core.Type  ( CLaSH/Core/Type.hs, interpreted )

CLaSH/Core/Type.hs:11:10: error:
    Not in scope: data constructor ‘Foo’
*** Exception: expectJust showModule
CallStack (from HasCallStack):
  error, called at compiler/utils/Maybes.hs:47:27 in ghc:Maybes
    • Ben Gamari
      Ben Gamari @bgamari ·
      Maintainer

      Hmm, I suspect the issue here is that we are not emitting the Typeable TyCon bindings into hi-boot files. This means things blow up when when the typechecker goes to construct Typeable evidence when only a SOURCE import of the module defining the type in question is in scope.

    • Ben Gamari
      Ben Gamari @bgamari ·
      Maintainer
      Trac metadata
      Trac field Value
      Differential revisions - → D2107, D2108
    • darchon
      darchon @trac-darchon ·
      Author

      Thanks for the patch!

    • Ben Gamari mentioned in commit 116088de

      mentioned in commit 116088de

    • Ben Gamari changed weight to 7

      changed weight to 7

    • Ben Gamari
      Ben Gamari @bgamari ·
      Maintainer
      Trac metadata
      Trac field Value
      Priority normal → high
    • Ben Gamari closed

      closed

    • Ben Gamari
      Ben Gamari @bgamari ·
      Maintainer

      A version of the patch referenced in ticket:11824#comment:119207 was merged to ghc-8.0 as 09665a7e.

      I'm going to try doing some refactoring in this area soon to make all of this a bit less opaque.

      Trac metadata
      Trac field Value
      Resolution Unresolved → ResolvedFixed
    • trac-import added compiler crash label

      added compiler crash label

    • Ben Gamari added broken test label

      added broken test label

    • Ben Gamari added Phigh label

      added Phigh label

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