[Haskell-cafe] Hackage: Tarball and package description of package mtl differ

Björn Peemöller bjp at informatik.uni-kiel.de
Wed Feb 10 14:09:38 UTC 2016

Hi Cafe,

I just wanted to install the mtl package for GHC 8.0.1-rc2, but
installation failed with

  Setup: Encountered missing dependencies:
  transformers ==0.4.*

Taking a look at the package description [1], it specifies

  build-depends: base < 6, transformers >= 0.4 && < 0.6

but the Cabal description in the tarball [2] says

  build-depends: base < 6, transformers == 0.4.*

Strangely, if I execute

  $ cabal unpack mtl-2.2.1

I obtain a version with the same specification as [1].

Does anybody has an explanation for this?


[1]: http://hackage.haskell.org/package/mtl-2.2.1/mtl.cabal
[2]: http://hackage.haskell.org/package/mtl-2.2.1/mtl-2.2.1.tar.gz

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