cabal-helper-wrapper bails out

[gilligan]

When I try to invoke ghc-mod (on my NixOS machine) I get the following output:

$ ghc-mod check src/Main.hs
cabal-helper-wrapper: Installing a private copy of Cabal because we couldn't
find the right version in your global/user package-db, this might take a
while but will only happen once per Cabal version you're using.

If anything goes horribly wrong just delete this directory and try again:
    /home/gilligan/.ghc-mod/cabal-helper

If you want to avoid this automatic installation altogether install
version 2.0.0.2 of Cabal manually (into your user or global package-db):
    $ cabal install Cabal --constraint "Cabal == 2.0.0.2"

[...]

CabalHelper/Licenses.hs:56:8: error:
    • Expecting one more argument to ‘CPackageIndex ModuleName’
      Expected a type, but ‘CPackageIndex ModuleName’ has kind ‘* -> *’
    • In the type signature:
        findTransitiveDependencies :: CPackageIndex ModuleName
                                      -> Set CInstalledPackageId -> Set CInstalledPackageId
ghc-mod: readCreateProcess: /nix/store/g5xd0f280n08zz1m8piirnnm2pf2kwbv-cabal-helper-0.7.3.0/libexec/x86_64-linux-ghc-8.0.2/cabal-helper-0.7.3.0/cabal-helper-wrapper "--with-ghc=ghc" "--with-ghc-pkg=ghc-pkg" "--with-cabal=cabal" "/home/gilligan/Development/jenkins-nixify" "/home/gilligan/Development/jenkins-nixify/dist" "package-db-stack" "entrypoints" "source-dirs" "ghc-options" "ghc-src-options" "ghc-pkg-options" "ghc-merged-pkg-options" "ghc-lang-options" "licenses" "flags" "config-flags" "non-default-config-flags" "compiler-version" (exit 1): failed

setup info

$ cabal --version
cabal-install version 2.0.0.0
compiled using version 2.0.0.2 of the Cabal library 

$ ghc --version
The Glorious Glasgow Haskell Compilation System, version 8.0.2

$ ghc-pkg list
/nix/store/d3rrijs9grhcc3v4xcqy999l25hsl0x0-ghc-8.0.2-with-packages/lib/ghc-8.0.2/package.conf.d
    Cabal-1.24.2.0
    MonadRandom-0.5.1
    StateVar-1.1.0.4
    aeson-1.1.2.0
    array-0.5.1.1
    attoparsec-0.13.1.0
    base-4.9.1.0
    base-compat-0.9.3
    base-orphans-0.6
    base64-bytestring-1.0.0.1
    bifunctors-5.4.2
    binary-0.8.3.0
    bytestring-0.10.8.1
    comonad-5.0.2
    containers-0.5.7.1
    contravariant-1.4
    deepseq-1.4.2.0
    directory-1.3.0.0
    distributive-0.5.3
    dlist-0.8.0.3
    either-4.4.1.1
    exceptions-0.8.3
    fail-4.9.0.0
    filepath-1.4.1.1
    free-4.12.4
    (ghc-8.0.2)
    ghc-boot-8.0.2
    (ghc-boot-th-8.0.2)
    ghc-prim-0.5.0.0
    ghci-8.0.2
    hashable-1.2.6.1
    haskeline-0.7.3.0
    hoopl-3.10.2.1
    hpc-0.6.0.3
    integer-gmp-1.0.0.1
    integer-logarithms-1.0.2
    mmorph-1.0.9
    monad-control-1.0.2.2
    mtl-2.2.1
    old-locale-1.0.0.7
    prelude-extras-0.4.0.3
    pretty-1.1.3.3
    primitive-0.6.2.0
    process-1.4.3.0
    profunctors-5.2.1
    random-1.1
    rts-1.0
    scientific-0.3.5.2
    semigroupoids-5.2.1
    semigroups-0.18.3
    stm-2.4.4.1
    tagged-0.8.5
    template-haskell-2.11.1.0
    terminfo-0.4.0.2
    text-1.2.2.2
    time-1.6.0.1
    time-locale-compat-0.1.1.3
    transformers-0.5.2.0
    transformers-base-0.4.4
    transformers-compat-0.5.1.4
    unix-2.7.2.1
    unordered-containers-0.2.8.0
    uuid-types-1.0.3
    vector-0.12.0.1
    void-0.7.2
    xhtml-3000.2.1

---

I am sorry in case this issue is a duplicate of an existing one but I honestly don't quite understand the details so I created a new one. I'll gladly close it if it is indeed a duplicate.

[DanielG]

See #905. Cabal-2.0 is simply not supported yet.