[Hackage] #925: Unused constraints result in "no available version"

[Hackage]

#925: Unused constraints result in "no available version"
----------------------------+-----------------------------------------------
  Reporter:  snoyberg       |        Owner:          
      Type:  defect         |       Status:  new     
  Priority:  normal         |    Milestone:          
 Component:  Cabal library  |      Version:  1.10.2.0
  Severity:  normal         |     Keywords:          
Difficulty:  unknown        |   Ghcversion:          
  Platform:                 |  
----------------------------+-----------------------------------------------
 When testing out my recently released cabal nirvana[1], Greg Weber pointed
 out than when building a package that does not use all of the constraints
 in the Nirvana file, you get a message such as:

     cabal: There is no available version of authenticate that satisfies
 ==1.0.0.1

 I confirmed that this happens with command-line constraints as well. A
 simple test case is to go into a non-Yesod project and run:

     cabal install --constraint "yesod >= 0.10"

 Unfortunately, this prevents nirvana from being of any use at all, which
 was our best shot at avoiding dependency hell.

 [1] http://hackage.haskell.org/package/cabal-nirvana

-- 
Ticket URL: <http://hackage.haskell.org/trac/hackage/ticket/925>
Hackage <http://haskell.org/cabal/>
Hackage: Cabal and related projects