I am trying to install git-annex 3.20120624 using cabal.  My currently installed version of git-annex is 3.20120615.  After a "cabal update", the build of git-annex fails:

    bram@falafel% cabal install git-annex
    Resolving dependencies...
    [1 of 4] Compiling Utility.SafeCommand ( /tmp/git-annex-3.20120624-4173/git-annex-3.20120624/Utility/SafeCommand.hs, /tmp/git-annex-3.20120624-4173/git-annex-3.20120624/dist/setup/Utility/SafeCommand.o )
    [2 of 4] Compiling Build.TestConfig ( /tmp/git-annex-3.20120624-4173/git-annex-3.20120624/Build/TestConfig.hs, /tmp/git-annex-3.20120624-4173/git-annex-3.20120624/dist/setup/Build/TestConfig.o )
    [3 of 4] Compiling Build.Configure  ( /tmp/git-annex-3.20120624-4173/git-annex-3.20120624/Build/Configure.hs, /tmp/git-annex-3.20120624-4173/git-annex-3.20120624/dist/setup/Build/Configure.o )
    [4 of 4] Compiling Main             ( /tmp/git-annex-3.20120624-4173/git-annex-3.20120624/Setup.hs, /tmp/git-annex-3.20120624-4173/git-annex-3.20120624/dist/setup/Main.o )
    Linking /tmp/git-annex-3.20120624-4173/git-annex-3.20120624/dist/setup/setup ...
      checking version... 3.20120624
      checking git... yes
      checking git version... 1.7.9.5
      checking cp -a... yes
      checking cp -p... yes
      checking cp --reflink=auto... yes
      checking uuid generator... uuid
      checking xargs -0... yes
      checking rsync... yes
      checking curl... no
      checking wget... yes
      checking bup... no
      checking gpg... yes
      checking lsof... yes
      checking ssh connection caching... yes
      checking sha1... sha1sum
      checking sha512... sha512sum
      checking sha224... sha224sum
      checking sha384... sha384sum
      checking sha256... sha256sum
    Configuring git-annex-3.20120624...
    Building git-annex-3.20120624...
    Preprocessing executable 'git-annex' for git-annex-3.20120624...
    [  1 of 183] Compiling Utility.Percentage ( Utility/Percentage.hs, dist/build/git-annex/git-annex-tmp/Utility/Percentage.o )
    [  2 of 183] Compiling Utility.Dot      ( Utility/Dot.hs, dist/build/git-annex/git-annex-tmp/Utility/Dot.o )
    [  3 of 183] Compiling Utility.ThreadLock ( Utility/ThreadLock.hs, dist/build/git-annex/git-annex-tmp/Utility/ThreadLock.o )
    [  4 of 183] Compiling Utility.Base64   ( Utility/Base64.hs, dist/build/git-annex/git-annex-tmp/Utility/Base64.o )
    [  5 of 183] Compiling Utility.DataUnits ( Utility/DataUnits.hs, dist/build/git-annex/git-annex-tmp/Utility/DataUnits.o )
    [  6 of 183] Compiling Utility.JSONStream ( Utility/JSONStream.hs, dist/build/git-annex/git-annex-tmp/Utility/JSONStream.o )
    [  7 of 183] Compiling Messages.JSON    ( Messages/JSON.hs, dist/build/git-annex/git-annex-tmp/Messages/JSON.o )
    [  8 of 183] Compiling Build.SysConfig  ( Build/SysConfig.hs, dist/build/git-annex/git-annex-tmp/Build/SysConfig.o )
    [  9 of 183] Compiling Types.KeySource  ( Types/KeySource.hs, dist/build/git-annex/git-annex-tmp/Types/KeySource.o )
    [ 10 of 183] Compiling Types.UUID       ( Types/UUID.hs, dist/build/git-annex/git-annex-tmp/Types/UUID.o )
    [ 11 of 183] Compiling Utility.State    ( Utility/State.hs, dist/build/git-annex/git-annex-tmp/Utility/State.o )
    [ 12 of 183] Compiling Types.Messages   ( Types/Messages.hs, dist/build/git-annex/git-annex-tmp/Types/Messages.o )
    [ 13 of 183] Compiling Types.TrustLevel ( Types/TrustLevel.hs, dist/build/git-annex/git-annex-tmp/Types/TrustLevel.o )
    [ 14 of 183] Compiling Types.BranchState ( Types/BranchState.hs, dist/build/git-annex/git-annex-tmp/Types/BranchState.o )
    [ 15 of 183] Compiling Git.Index        ( Git/Index.hs, dist/build/git-annex/git-annex-tmp/Git/Index.o )
    [ 16 of 183] Compiling Utility.PartialPrelude ( Utility/PartialPrelude.hs, dist/build/git-annex/git-annex-tmp/Utility/PartialPrelude.o )
    [ 17 of 183] Compiling Utility.Format   ( Utility/Format.hs, dist/build/git-annex/git-annex-tmp/Utility/Format.o )
    [ 18 of 183] Compiling Utility.FileSystemEncoding ( Utility/FileSystemEncoding.hs, dist/build/git-annex/git-annex-tmp/Utility/FileSystemEncoding.o )
    [ 19 of 183] Compiling Utility.Touch    ( dist/build/git-annex/git-annex-tmp/Utility/Touch.hs, dist/build/git-annex/git-annex-tmp/Utility/Touch.o )
    [ 20 of 183] Compiling Utility.Monad    ( Utility/Monad.hs, dist/build/git-annex/git-annex-tmp/Utility/Monad.o )
    [ 21 of 183] Compiling Utility.Path     ( Utility/Path.hs, dist/build/git-annex/git-annex-tmp/Utility/Path.o )
    [ 22 of 183] Compiling Utility.SafeCommand ( Utility/SafeCommand.hs, dist/build/git-annex/git-annex-tmp/Utility/SafeCommand.o )
    [ 23 of 183] Compiling Utility.RsyncFile ( Utility/RsyncFile.hs, dist/build/git-annex/git-annex-tmp/Utility/RsyncFile.o )
    [ 24 of 183] Compiling Utility.Exception ( Utility/Exception.hs, dist/build/git-annex/git-annex-tmp/Utility/Exception.o )
    [ 25 of 183] Compiling Utility.TempFile ( Utility/TempFile.hs, dist/build/git-annex/git-annex-tmp/Utility/TempFile.o )
    [ 26 of 183] Compiling Utility.Directory ( Utility/Directory.hs, dist/build/git-annex/git-annex-tmp/Utility/Directory.o )
    [ 27 of 183] Compiling Utility.Misc     ( Utility/Misc.hs, dist/build/git-annex/git-annex-tmp/Utility/Misc.o )
    [ 28 of 183] Compiling Git.Types        ( Git/Types.hs, dist/build/git-annex/git-annex-tmp/Git/Types.o )
    [ 29 of 183] Compiling Common           ( Common.hs, dist/build/git-annex/git-annex-tmp/Common.o )
    [ 30 of 183] Compiling Utility.FileMode ( Utility/FileMode.hs, dist/build/git-annex/git-annex-tmp/Utility/FileMode.o )
    [ 31 of 183] Compiling Git              ( Git.hs, dist/build/git-annex/git-annex-tmp/Git.o )
    [ 32 of 183] Compiling Git.Command      ( Git/Command.hs, dist/build/git-annex/git-annex-tmp/Git/Command.o )
    [ 33 of 183] Compiling Git.Ref          ( Git/Ref.hs, dist/build/git-annex/git-annex-tmp/Git/Ref.o )
    [ 34 of 183] Compiling Git.FilePath     ( Git/FilePath.hs, dist/build/git-annex/git-annex-tmp/Git/FilePath.o )
    [ 35 of 183] Compiling Utility.Matcher  ( Utility/Matcher.hs, dist/build/git-annex/git-annex-tmp/Utility/Matcher.o )
    [ 36 of 183] Compiling Utility.Gpg      ( Utility/Gpg.hs, dist/build/git-annex/git-annex-tmp/Utility/Gpg.o )
    [ 37 of 183] Compiling Types.Crypto     ( Types/Crypto.hs, dist/build/git-annex/git-annex-tmp/Types/Crypto.o )
    [ 38 of 183] Compiling Types.Key        ( Types/Key.hs, dist/build/git-annex/git-annex-tmp/Types/Key.o )
    [ 39 of 183] Compiling Types.Backend    ( Types/Backend.hs, dist/build/git-annex/git-annex-tmp/Types/Backend.o )
    [ 40 of 183] Compiling Types.Remote     ( Types/Remote.hs, dist/build/git-annex/git-annex-tmp/Types/Remote.o )
    [ 41 of 183] Compiling Git.Sha          ( Git/Sha.hs, dist/build/git-annex/git-annex-tmp/Git/Sha.o )
    [ 42 of 183] Compiling Git.Branch       ( Git/Branch.hs, dist/build/git-annex/git-annex-tmp/Git/Branch.o )
    [ 43 of 183] Compiling Git.UpdateIndex  ( Git/UpdateIndex.hs, dist/build/git-annex/git-annex-tmp/Git/UpdateIndex.o )
    [ 44 of 183] Compiling Git.Queue        ( Git/Queue.hs, dist/build/git-annex/git-annex-tmp/Git/Queue.o )
    [ 45 of 183] Compiling Git.Url          ( Git/Url.hs, dist/build/git-annex/git-annex-tmp/Git/Url.o )
    [ 46 of 183] Compiling Git.Construct    ( Git/Construct.hs, dist/build/git-annex/git-annex-tmp/Git/Construct.o )
    [ 47 of 183] Compiling Git.Config       ( Git/Config.hs, dist/build/git-annex/git-annex-tmp/Git/Config.o )
    [ 48 of 183] Compiling Git.SharedRepository ( Git/SharedRepository.hs, dist/build/git-annex/git-annex-tmp/Git/SharedRepository.o )
    [ 49 of 183] Compiling Git.Version      ( Git/Version.hs, dist/build/git-annex/git-annex-tmp/Git/Version.o )
    [ 50 of 183] Compiling Utility.CoProcess ( Utility/CoProcess.hs, dist/build/git-annex/git-annex-tmp/Utility/CoProcess.o )
    [ 51 of 183] Compiling Git.HashObject   ( Git/HashObject.hs, dist/build/git-annex/git-annex-tmp/Git/HashObject.o )
    [ 52 of 183] Compiling Git.CatFile      ( Git/CatFile.hs, dist/build/git-annex/git-annex-tmp/Git/CatFile.o )
    [ 53 of 183] Compiling Git.UnionMerge   ( Git/UnionMerge.hs, dist/build/git-annex/git-annex-tmp/Git/UnionMerge.o )
    [ 54 of 183] Compiling Git.CheckAttr    ( Git/CheckAttr.hs, dist/build/git-annex/git-annex-tmp/Git/CheckAttr.o )
    [ 55 of 183] Compiling Annex            ( Annex.hs, dist/build/git-annex/git-annex-tmp/Annex.o )
    [ 56 of 183] Compiling Types.Option     ( Types/Option.hs, dist/build/git-annex/git-annex-tmp/Types/Option.o )
    [ 57 of 183] Compiling Types            ( Types.hs, dist/build/git-annex/git-annex-tmp/Types.o )
    [ 58 of 183] Compiling Messages         ( Messages.hs, dist/build/git-annex/git-annex-tmp/Messages.o )
    [ 59 of 183] Compiling Types.Command    ( Types/Command.hs, dist/build/git-annex/git-annex-tmp/Types/Command.o )
    [ 60 of 183] Compiling Locations        ( Locations.hs, dist/build/git-annex/git-annex-tmp/Locations.o )
    [ 61 of 183] Compiling Common.Annex     ( Common/Annex.hs, dist/build/git-annex/git-annex-tmp/Common/Annex.o )
    [ 62 of 183] Compiling Annex.Exception  ( Annex/Exception.hs, dist/build/git-annex/git-annex-tmp/Annex/Exception.o )
    [ 63 of 183] Compiling Annex.BranchState ( Annex/BranchState.hs, dist/build/git-annex/git-annex-tmp/Annex/BranchState.o )
    [ 64 of 183] Compiling Annex.CatFile    ( Annex/CatFile.hs, dist/build/git-annex/git-annex-tmp/Annex/CatFile.o )
    [ 65 of 183] Compiling Annex.Perms      ( Annex/Perms.hs, dist/build/git-annex/git-annex-tmp/Annex/Perms.o )
    [ 66 of 183] Compiling Annex.Journal    ( Annex/Journal.hs, dist/build/git-annex/git-annex-tmp/Annex/Journal.o )
    [ 67 of 183] Compiling Annex.Branch     ( Annex/Branch.hs, dist/build/git-annex/git-annex-tmp/Annex/Branch.o )
    [ 68 of 183] Compiling Crypto           ( Crypto.hs, dist/build/git-annex/git-annex-tmp/Crypto.o )
    [ 69 of 183] Compiling Usage            ( Usage.hs, dist/build/git-annex/git-annex-tmp/Usage.o )
    [ 70 of 183] Compiling Annex.CheckAttr  ( Annex/CheckAttr.hs, dist/build/git-annex/git-annex-tmp/Annex/CheckAttr.o )
    [ 71 of 183] Compiling Remote.Helper.Special ( Remote/Helper/Special.hs, dist/build/git-annex/git-annex-tmp/Remote/Helper/Special.o )
    [ 72 of 183] Compiling Logs.Presence    ( Logs/Presence.hs, dist/build/git-annex/git-annex-tmp/Logs/Presence.o )
    [ 73 of 183] Compiling Logs.Location    ( Logs/Location.hs, dist/build/git-annex/git-annex-tmp/Logs/Location.o )
    [ 74 of 183] Compiling Logs.Web         ( Logs/Web.hs, dist/build/git-annex/git-annex-tmp/Logs/Web.o )
    [ 75 of 183] Compiling Annex.LockPool   ( Annex/LockPool.hs, dist/build/git-annex/git-annex-tmp/Annex/LockPool.o )
    [ 76 of 183] Compiling Backend.SHA      ( Backend/SHA.hs, dist/build/git-annex/git-annex-tmp/Backend/SHA.o )
    [ 77 of 183] Compiling Backend.WORM     ( Backend/WORM.hs, dist/build/git-annex/git-annex-tmp/Backend/WORM.o )
    [ 78 of 183] Compiling Backend.URL      ( Backend/URL.hs, dist/build/git-annex/git-annex-tmp/Backend/URL.o )
    [ 79 of 183] Compiling Assistant.ThreadedMonad ( Assistant/ThreadedMonad.hs, dist/build/git-annex/git-annex-tmp/Assistant/ThreadedMonad.o )
    [ 80 of 183] Compiling Logs.UUIDBased   ( Logs/UUIDBased.hs, dist/build/git-annex/git-annex-tmp/Logs/UUIDBased.o )
    [ 81 of 183] Compiling Logs.Remote      ( Logs/Remote.hs, dist/build/git-annex/git-annex-tmp/Logs/Remote.o )
    [ 82 of 183] Compiling Utility.DiskFree ( Utility/DiskFree.hs, dist/build/git-annex/git-annex-tmp/Utility/DiskFree.o )
    [ 83 of 183] Compiling Utility.Url      ( Utility/Url.hs, dist/build/git-annex/git-annex-tmp/Utility/Url.o )
    [ 84 of 183] Compiling Utility.CopyFile ( Utility/CopyFile.hs, dist/build/git-annex/git-annex-tmp/Utility/CopyFile.o )
    [ 85 of 183] Compiling Git.LsFiles      ( Git/LsFiles.hs, dist/build/git-annex/git-annex-tmp/Git/LsFiles.o )
    [ 86 of 183] Compiling Git.AutoCorrect  ( Git/AutoCorrect.hs, dist/build/git-annex/git-annex-tmp/Git/AutoCorrect.o )
    [ 87 of 183] Compiling Git.CurrentRepo  ( Git/CurrentRepo.hs, dist/build/git-annex/git-annex-tmp/Git/CurrentRepo.o )
    [ 88 of 183] Compiling Utility.Daemon   ( Utility/Daemon.hs, dist/build/git-annex/git-annex-tmp/Utility/Daemon.o )
    [ 89 of 183] Compiling Utility.LogFile  ( Utility/LogFile.hs, dist/build/git-annex/git-annex-tmp/Utility/LogFile.o )
    [ 90 of 183] Compiling Utility.ThreadScheduler ( Utility/ThreadScheduler.hs, dist/build/git-annex/git-annex-tmp/Utility/ThreadScheduler.o )
    [ 91 of 183] Compiling Assistant.DaemonStatus ( Assistant/DaemonStatus.hs, dist/build/git-annex/git-annex-tmp/Assistant/DaemonStatus.o )
    [ 92 of 183] Compiling Utility.Types.DirWatcher ( Utility/Types/DirWatcher.hs, dist/build/git-annex/git-annex-tmp/Utility/Types/DirWatcher.o )
    [ 93 of 183] Compiling Utility.INotify  ( Utility/INotify.hs, dist/build/git-annex/git-annex-tmp/Utility/INotify.o )
    [ 94 of 183] Compiling Utility.DirWatcher ( Utility/DirWatcher.hs, dist/build/git-annex/git-annex-tmp/Utility/DirWatcher.o )
    [ 95 of 183] Compiling Utility.Lsof     ( Utility/Lsof.hs, dist/build/git-annex/git-annex-tmp/Utility/Lsof.o )
    [ 96 of 183] Compiling Git.Merge        ( Git/Merge.hs, dist/build/git-annex/git-annex-tmp/Git/Merge.o )
    [ 97 of 183] Compiling Git.Filename     ( Git/Filename.hs, dist/build/git-annex/git-annex-tmp/Git/Filename.o )
    [ 98 of 183] Compiling Git.LsTree       ( Git/LsTree.hs, dist/build/git-annex/git-annex-tmp/Git/LsTree.o )
    [ 99 of 183] Compiling Config           ( Config.hs, dist/build/git-annex/git-annex-tmp/Config.o )
    [100 of 183] Compiling Annex.UUID       ( Annex/UUID.hs, dist/build/git-annex/git-annex-tmp/Annex/UUID.o )
    [101 of 183] Compiling Logs.UUID        ( Logs/UUID.hs, dist/build/git-annex/git-annex-tmp/Logs/UUID.o )
    [102 of 183] Compiling Backend          ( Backend.hs, dist/build/git-annex/git-annex-tmp/Backend.o )
    [103 of 183] Compiling Remote.Helper.Hooks ( Remote/Helper/Hooks.hs, dist/build/git-annex/git-annex-tmp/Remote/Helper/Hooks.o )
    [104 of 183] Compiling Remote.Helper.Encryptable ( Remote/Helper/Encryptable.hs, dist/build/git-annex/git-annex-tmp/Remote/Helper/Encryptable.o )
    [105 of 183] Compiling Annex.Queue      ( Annex/Queue.hs, dist/build/git-annex/git-annex-tmp/Annex/Queue.o )
    [106 of 183] Compiling Annex.Content    ( Annex/Content.hs, dist/build/git-annex/git-annex-tmp/Annex/Content.o )
    [107 of 183] Compiling Remote.S3        ( Remote/S3.hs, dist/build/git-annex/git-annex-tmp/Remote/S3.o )
    [108 of 183] Compiling Remote.Directory ( Remote/Directory.hs, dist/build/git-annex/git-annex-tmp/Remote/Directory.o )
    [109 of 183] Compiling Remote.Rsync     ( Remote/Rsync.hs, dist/build/git-annex/git-annex-tmp/Remote/Rsync.o )
    [110 of 183] Compiling Remote.Web       ( Remote/Web.hs, dist/build/git-annex/git-annex-tmp/Remote/Web.o )
    [111 of 183] Compiling Remote.Hook      ( Remote/Hook.hs, dist/build/git-annex/git-annex-tmp/Remote/Hook.o )
    [112 of 183] Compiling Upgrade.V2       ( Upgrade/V2.hs, dist/build/git-annex/git-annex-tmp/Upgrade/V2.o )
    [113 of 183] Compiling Assistant.Changes ( Assistant/Changes.hs, dist/build/git-annex/git-annex-tmp/Assistant/Changes.o )
    
    Assistant/Changes.hs:73:30:
        Not in scope: `tryReadTChan'
        Perhaps you meant `readTChan' (imported from Control.Concurrent.STM)
    cabal: Error: some packages failed to install:
    git-annex-3.20120624 failed during the building phase. The exception was:
    ExitFailure 1

This is using haskell-platform 2012.1.0.0~debian1 on Ubuntu 12.04.

> Turns out it needs version 2.3 of the STM library. (libghc-stm-dev
> package). I've made cabal detect an older version and skip building
> the new `git annex watch` command, so you'll be able to build the next
> release. [[done]] --[[Joey]]
