cabal install fails with empty conflict set

[Björn Peemöller]

Hi,

I am trying to install a cabal package in a fresh, clean sandbox, but
cabal fails with:

    cabal: Could not resolve dependencies:
    Dependency tree exhaustively searched.

I'm using

    $ cabal -V
    cabal-install version 1.20.0.1
    using version 1.20.0.0 of the Cabal library
    $ ghc -V
    The Glorious Glasgow Haskell Compilation System, version 7.8.2

Even when I try -v3 I do not get much more information:

$cabal install --only-dependencies -v3
Using a sandbox located at
/home/bjp/projects/curry-frontend/.cabal-sandbox
Searching for ghc in path.
Found ghc at /home/bjp/.ghc-config/ghc/bin/ghc
("/home/bjp/.ghc-config/ghc/bin/ghc",["--numeric-version"])
/home/bjp/.ghc-config/ghc/bin/ghc is version 7.8.2
looking for tool ghc-pkg near compiler in
/home/bjp/.ghc-config/ghc/bin
found ghc-pkg in /home/bjp/.ghc-config/ghc/bin/ghc-pkg
("/home/bjp/.ghc-config/ghc/bin/ghc-pkg",["--version"])
/home/bjp/.ghc-config/ghc/bin/ghc-pkg is version 7.8.2
("/home/bjp/.ghc-config/ghc/bin/ghc",["--supported-languages"])
("/home/bjp/.ghc-config/ghc/bin/ghc",["--info"])
The package database already exists:
/home/bjp/projects/curry-frontend/.cabal-sandbox/x86_64-linux-ghc-7.8.2-packages.conf.d
Reading available packages...
Reading available packages...
Reading installed packages...
("/home/bjp/.ghc-config/ghc/bin/ghc-pkg",["dump","--package-db=/home/bjp/projects/curry-frontend/.cabal-sandbox/x86_64-linux-ghc-7.8.2-packages.conf.d","-v0"])
("/home/bjp/.ghc-config/ghc/bin/ghc",["--print-libdir"])
Found no modified add-source deps.
Reading installed packages...
("/home/bjp/.ghc-config/ghc/bin/ghc-pkg",["dump","--global","-v0"])
("/home/bjp/.ghc-config/ghc/bin/ghc-pkg",["dump","--package-db=/home/bjp/projects/curry-frontend/.cabal-sandbox/x86_64-linux-ghc-7.8.2-packages.conf.d","-v0"])
("/home/bjp/.ghc-config/ghc/bin/ghc",["--print-libdir"])
Reading available packages...
Choosing modular solver.
Resolving dependencies...
[__0] trying: curry-frontend-0.3.10 (user goal)
[__1] trying: base-4.7.0.0/installed-018... (dependency of
curry-frontend-0.3.10)
[__2] trying: rts-1.0/installedbuil... (dependency of
base-4.7.0.0/installed-018...)
[__3] trying: integer-gmp-0.5.1.0/installed-dc4... (dependency of
base-4.7.0.0/installed-018...)
[__4] trying: ghc-prim-0.3.1.0/installed-948... (dependency of
base-4.7.0.0/installed-018...)
[__5] trying: curry-frontend-0.3.10:+split-syb
[__6] trying: syb-0.4.1 (dependency of curry-frontend-0.3.10)
[__7] trying: syb-0.4.1:!test
[__8] trying: transformers-0.3.0.0/installed-7df... (dependency of
curry-frontend-0.3.10)
[__9] trying: process-1.2.0.0/installed-eaf... (dependency of
curry-frontend-0.3.10)
[_10] trying: unix-2.7.0.1/installed-23f... (dependency of
process-1.2.0.0/installed-eaf...)
[_11] trying: time-1.4.2/installed-b47... (dependency of
unix-2.7.0.1/installed-23f...)
[_12] trying: old-locale-1.0.0.6/installed-be1... (dependency of
time-1.4.2/installed-b47...)
[_13] trying: bytestring-0.10.4.0/installed-7de... (dependency of
unix-2.7.0.1/installed-23f...)
[_14] trying: deepseq-1.3.0.2/installed-716... (dependency of
process-1.2.0.0/installed-eaf...)
[_15] trying: array-0.5.0.0/installed-9f2... (dependency of
deepseq-1.3.0.2/installed-716...)
[_16] trying: mtl-2.1.2/installed-d71... (dependency of
curry-frontend-0.3.10)
[_17] trying: either-4.1.2 (dependency of curry-frontend-0.3.10)
[_18] trying: transformers-base-0.4.2 (dependency of either-4.1.2)
[_19] trying: transformers-base-0.4.2:+orphaninstances
[_20] trying: semigroupoids-4.0.2 (dependency of either-4.1.2)
[_21] trying: distributive-0.4.4 (dependency of semigroupoids-4.0.2)
[_22] trying: distributive-0.4.4:-lib-werror
[_23] trying: distributive-0.4.4:!test
[_24] trying: transformers-compat-0.3.2 (dependency of distributive-0.4.4)
[_25] trying: transformers-compat-0.3.2:-transformers3
[__0] fail (backjumping, conflict set: )
cabal: Could not resolve dependencies:
Dependency tree exhaustively searched.

Note: when using a sandbox, all packages are required to have consistent
dependencies. Try reinstalling/unregistering the offending packages or
recreating the sandbox.


Does anybody have an idea what the problem is?

Best Regards,
Björn