Fails to compile with template-haskell-2.11

[hvr]

See also https://ghc.haskell.org/trac/ghc/wiki/Migration/8.0#template-haskell-2.11.0.0

Building instant-generics-0.5...
/opt/ghc/8.0.1/bin/ghc-pkg init dist/dist-sandbox-1a704d6f/package.conf.inplace
Preprocessing library instant-generics-0.5...
Building library...
creating dist/dist-sandbox-1a704d6f/build
/opt/ghc/8.0.1/bin/ghc --make -fbuilding-cabal-package -O -static -dynamic-too -dynosuf dyn_o -dynhisuf dyn_hi -outputdir dist/dist-sandbox-1a704d6f/build -odir dist/dist-sandbox-1a704d6f/build -hidir dist/dist-sandbox-1a704d6f/build -stubdir dist/dist-sandbox-1a704d6f/build -i -idist/dist-sandbox-1a704d6f/build -isrc -idist/dist-sandbox-1a704d6f/build/autogen -Idist/dist-sandbox-1a704d6f/build/autogen -Idist/dist-sandbox-1a704d6f/build -optP-include -optPdist/dist-sandbox-1a704d6f/build/autogen/cabal_macros.h -this-unit-id instant-generics-0.5-DvvHUg9GuuTJYIaUcXJmdk -hide-all-packages -no-user-package-db -package-db /tmp/extra28344172154/.cabal-sandbox/x86_64-linux-ghc-8.0.0.20160221-packages.conf.d -package-db dist/dist-sandbox-1a704d6f/package.conf.inplace -package-id base-4.9.0.0 -package-id containers-0.5.7.1 -package-id syb-0.6-C65vWCsht6A8uLstpQIXyj -package-id template-haskell-2.11.0.0 -XHaskell98 Generics.Instant Generics.Instant.Base Generics.Instant.TH Generics.Instant.Instances Generics.Instant.Functions Generics.Instant.Functions.Show Generics.Instant.Functions.Empty Generics.Instant.Functions.Enum Generics.Instant.Functions.Eq -Wall

src/Generics/Instant/Functions/Show.hs:4:14: warning:
    -XOverlappingInstances is deprecated: instead use per-instance pragmas OVERLAPPING/OVERLAPPABLE/OVERLAPS

src/Generics/Instant/Functions/Empty.hs:4:14: warning:
    -XOverlappingInstances is deprecated: instead use per-instance pragmas OVERLAPPING/OVERLAPPABLE/OVERLAPS

src/Generics/Instant/Functions/Enum.hs:6:14: warning:
    -XOverlappingInstances is deprecated: instead use per-instance pragmas OVERLAPPING/OVERLAPPABLE/OVERLAPS

src/Generics/Instant/Functions/Eq.hs:3:14: warning:
    -XOverlappingInstances is deprecated: instead use per-instance pragmas OVERLAPPING/OVERLAPPABLE/OVERLAPS
[1 of 9] Compiling Generics.Instant.Base ( src/Generics/Instant/Base.hs, dist/dist-sandbox-1a704d6f/build/Generics/Instant/Base.o )
[2 of 9] Compiling Generics.Instant.Instances ( src/Generics/Instant/Instances.hs, dist/dist-sandbox-1a704d6f/build/Generics/Instant/Instances.o )
[3 of 9] Compiling Generics.Instant.TH ( src/Generics/Instant/TH.hs, dist/dist-sandbox-1a704d6f/build/Generics/Instant/TH.o )

src/Generics/Instant/TH.hs:74:22: error:
    • The constructor ‘DataD’ should have 6 arguments, but has been given 5
    • In the pattern: DataD _ _ vs cs _
      In the pattern: TyConI (DataD _ _ vs cs _)
      In a case alternative: TyConI (DataD _ _ vs cs _) -> (vs, cs)

src/Generics/Instant/TH.hs:238:13: error:
    • The constructor ‘DataD’ should have 6 arguments, but has been given 5
    • In the pattern: DataD _ n _ cs _
      In the pattern: TyConI (DataD _ n _ cs _)
      In a case alternative: TyConI (DataD _ n _ cs _) -> mkInstance n cs

src/Generics/Instant/TH.hs:248:24: error:
    • The constructor ‘DataD’ should have 6 arguments, but has been given 5
    • In the pattern: DataD _ _ tv _ _
      In the pattern: TyConI (DataD _ _ tv _ _)
      In an equation for ‘typeVariables’:
          typeVariables (TyConI (DataD _ _ tv _ _)) = tv

src/Generics/Instant/TH.hs:272:3: error:
    • Couldn't match expected type ‘Q Dec’
                  with actual type ‘CxtQ -> DecQ’
    • Probable cause: ‘dataD’ is applied to too few arguments
      In the expression: dataD (cxt []) (genName [dt, n]) [] [] []
      In an equation for ‘mkConstrData’:
          mkConstrData dt (NormalC n _)
            = dataD (cxt []) (genName [dt, n]) [] [] []

src/Generics/Instant/TH.hs:272:39: error:
    • Couldn't match expected type ‘Maybe Kind’ with actual type ‘[t1]’
    • In the fourth argument of ‘dataD’, namely ‘[]’
      In the expression: dataD (cxt []) (genName [dt, n]) [] [] []
      In an equation for ‘mkConstrData’:
          mkConstrData dt (NormalC n _)
            = dataD (cxt []) (genName [dt, n]) [] [] []

src/Generics/Instant/TH.hs:299:18: error:
    • The constructor ‘DataConI’ should have 3 arguments, but has been given 4
    • In the pattern: DataConI _ _ _ f
      In a case alternative: DataConI _ _ _ f -> convertFixity f
      In the expression:
        case i of {
          DataConI _ _ _ f -> convertFixity f
          _ -> Prefix }

src/Generics/Instant/TH.hs:320:10: error:
    • The constructor ‘DataD’ should have 6 arguments, but has been given 5
    • In the pattern: DataD _ dt vs cs _
      In a case alternative:
          (DataD _ dt vs cs _)
            -> (foldBal'
                  sum
                  (error "Empty datatypes are not supported.")
                  (map
                     (repConGADT
                        (dt, tyVarBndrsToNames vs) repVs (extractIndices vs cs))
                     cs))
      In a stmt of a 'do' block:
        case i of {
          (DataD _ dt vs cs _)
            -> (foldBal'
                  sum
                  (error "Empty datatypes are not supported.")
                  (map
                     (repConGADT
                        (dt, tyVarBndrsToNames vs) repVs (extractIndices vs cs))
                     cs))
          (NewtypeD _ dt vs c _)
            -> repConGADT
                 (dt, tyVarBndrsToNames vs) repVs (extractIndices vs [c]) c
          (TySynD t _ _) -> error "type synonym?"
          _ -> error "unknown construct" }

src/Generics/Instant/TH.hs:412:18: error:
    • The constructor ‘DataD’ should have 6 arguments, but has been given 5
    • In the pattern: DataD _ n _ cs _
      In an equation for ‘genExTyFamInsts’:
          genExTyFamInsts (DataD _ n _ cs _)
            = fmap concat $ mapM (genExTyFamInsts' n) cs

src/Generics/Instant/TH.hs:514:25: error:
    • The constructor ‘DataD’ should have 6 arguments, but has been given 5
    • In the pattern: DataD _ dt vs cs _
      In the pattern: TyConI (DataD _ dt vs cs _)
      In a case alternative:
          TyConI (DataD _ dt vs cs _)
            -> zipWith
                 (fromCon wrapE ns (dt, map tyVarBndrToName vs) (length cs))
                 [1 .. ]
                 cs

src/Generics/Instant/TH.hs:531:25: error:
    • The constructor ‘DataD’ should have 6 arguments, but has been given 5
    • In the pattern: DataD _ dt vs cs _
      In the pattern: TyConI (DataD _ dt vs cs _)
      In a case alternative:
          TyConI (DataD _ dt vs cs _)
            -> zipWith
                 (toCon wrapP ns (dt, map tyVarBndrToName vs) (length cs))
                 [1 .. ]
                 cs

[dreixel]

Thanks for the report. I'm afraid I don't have time to make fixes to instant-generics at the moment, but pull requests are very welcome!

[k0001]

@hvr @dreixel I took a stab at this. Please take a look at k0001@141ea67

It compiles alright, most of the required changes were quite mechanical, but now when running the test suite for instant-aeson (as of k0001/instant-aeson@2112314), for example, I get an error saying:

Preprocessing test suite 'tests' for instant-aeson-0.2.0.1...
[1 of 1] Compiling Main             ( tests/Main.hs, dist/build/tests/tests-tmp/Main.dyn_o )
tests/Main.hs:40:1-21: Splicing declarations
    GI.deriveAll ''Either
  ======>
    data Either_Left_
    data Either_Right_
    instance GI.Constructor Either_Left_ where
      GI.conName _ = "Left"
    instance GI.Constructor Either_Right_ where
      GI.conName _ = "Right"
    type RepEither_ (a_a9k7 :: ghc-prim-0.5.0.0:GHC.Types.Type)
                    (b_a9k8 :: ghc-prim-0.5.0.0:GHC.Types.Type) =
(GI.:+:) (GI.CEq Either_Left_ () () (GI.Rec a_a9k7)) (GI.CEq Either_Right_ () () (GI.Rec b_a9k8))
    instance GI.Representable (Either a_a9k7 b_a9k8) where
      type GI.Rep (Either a_a9k7 b_a9k8) = RepEither_ a_a9k7 b_a9k8
      GI.from (Left f0) = GI.L (GI.C (GI.Rec f0))
      GI.from (Right f0) = GI.R (GI.C (GI.Rec f0))
      GI.to (GI.L (GI.C (GI.Rec f0))) = Left f0
      GI.to (GI.R (GI.C (GI.Rec f0))) = Right f0
tests/Main.hs:53:1-17: Splicing declarations
    GI.deriveAll ''ZZ
  ======>
    data ZZ_ZZ1_
    data ZZ_ZZ2_
    data ZZ_ZZ3_
    instance GI.Constructor ZZ_ZZ1_ where
      GI.conName _ = "ZZ1"
    instance GI.Constructor ZZ_ZZ2_ where
      GI.conName _ = "ZZ2"
    instance GI.Constructor ZZ_ZZ3_ where
      GI.conName _ = "ZZ3"
    type RepZZ_ =
        (GI.:+:) (GI.CEq ZZ_ZZ1_ () () (GI.Rec Int)) ((GI.:+:) (GI.CEq ZZ_ZZ2_ () () (GI.Rec Char)) (GI.CEq ZZ_ZZ3_ () () (GI.Rec ZZ)))
    instance GI.Representable ZZ where
      type GI.Rep ZZ = RepZZ_
      GI.from (ZZ1 f0) = GI.L (GI.C (GI.Rec f0))
      GI.from (ZZ2 f0) = GI.R (GI.L (GI.C (GI.Rec f0)))
      GI.from (ZZ3 f0) = GI.R (GI.R (GI.C (GI.Rec f0)))
      GI.to (GI.L (GI.C (GI.Rec f0))) = ZZ1 f0
      GI.to (GI.R (GI.L (GI.C (GI.Rec f0)))) = ZZ2 f0
      GI.to (GI.R (GI.R (GI.C (GI.Rec f0)))) = ZZ3 f0
tests/Main.hs:68:1-19: Splicing declarations
    GI.deriveAll ''Foo1
  ======>
    data Foo1_Foo1_1_
    data Foo1_Foo1_2_
    instance GI.Constructor Foo1_Foo1_1_ where
      GI.conName _ = "Foo1_1"
    instance GI.Constructor Foo1_Foo1_2_ where
      GI.conName _ = "Foo1_2"
    type RepFoo1_ (a_adPH :: ghc-prim-0.5.0.0:GHC.Types.Type) =
        (GI.:+:) (GI.CEq Foo1_Foo1_1_ () () (GI.Rec Bool)) (GI.CEq Foo1_Foo1_2_ () () (GI.Rec a_adPI))
    instance GI.Representable (Foo1 a_adPH) where
      type GI.Rep (Foo1 a_adPH) = RepFoo1_ a_adPH
      GI.from (Foo1_1 f0) = GI.L (GI.C (GI.Rec f0))
      GI.from (Foo1_2 f0) = GI.R (GI.C (GI.Rec f0))
      GI.to (GI.L (GI.C (GI.Rec f0))) = Foo1_1 f0
      GI.to (GI.R (GI.C (GI.Rec f0))) = Foo1_2 f0

tests/Main.hs:68:1: error:
    The exact Name ‘a_adPI’ is not in scope
      Probable cause: you used a unique Template Haskell name (NameU),
      perhaps via newName, but did not bind it
      If that's it, then -ddump-splices might be useful

I'm afraid I won't be able to dedicate more time to this anytime soon, but if somebody wants to take over, please do :)

[jwaldmann]

Bumping this issue (it blocks harmtrace on ghc-8)

[serras]

I have made a pull request (#5) which adds support for both GHC 8.0 and 8.2.
I have implemented it from scratch, and the implementation does not suffer the bug pointed out by @k0001. I think it is because in my code I have a slightly different definition for repCon:

repCon (dt, vs) (ForallC tyvs cxt c) (t1,t2) =
  map (ForallT tyvs cxt) <$> repCon (dt, vs) c (t1,t2)

which prevents the variables to get out of scope. Alas, one still gets an error message in the test-suit of instant-aeson:

    • Illegal polymorphic type:
        forall a. GI.CEq Foo1_Foo1_2_ () () (GI.Rec a)
      GHC doesn't yet support impredicative polymorphism
    • In the type synonym declaration for ‘RepFoo1_’

but at least the compiler does not crash.