[Hackage] #597: non-exhaustive patterns when trying to install base

[Hackage]

#597: non-exhaustive patterns when trying to install base
---------------------------------+------------------------------------------
  Reporter:  guest               |        Owner:         
      Type:  defect              |       Status:  new    
  Priority:  normal              |    Milestone:         
 Component:  cabal-install tool  |      Version:  1.6.0.2
  Severity:  minor               |   Resolution:         
  Keywords:                      |   Difficulty:  normal 
Ghcversion:  6.10.1              |     Platform:         
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Changes (by duncan):

  * difficulty:  unknown => normal
  * summary:  non-exhaustive patterns in lambda => non-exhaustive patterns
              when trying to install base
  * severity:  normal => minor
  * platform:  Mac OS =>

Comment:

 The key bit is:
 {{{
 $ cabal install base
 Resolving dependencies...
 cabal: Distribution/Client/Dependency/TopDown.hs:170:37-73: Non-exhaustive
 patterns in lambda
 }}}

 Yep, trying to install base will not work. We should produce a better
 error message though.

 As for the other bits, your getting confused about the error messages. The
 message you get when the profiled version is missing is different. The
 regex-dfa-0.91 package really is from the ghc-6.6 era and is missing the
 dependency on the containers package.

 The problem when you build containers is that the package does not specify
 the version of base that it needs. It needs version 4 but does not say so,
 and by default cabal will pick base 3, because that's the choice that
 makes all the older stuff work. But as I say, you've got the profiled
 version of containers already, so don't re-install it.

-- 
Ticket URL: <http://hackage.haskell.org/trac/hackage/ticket/597#comment:1>
Hackage <http://haskell.org/cabal/>
Hackage: Cabal and related projects