$ sudo port install haddock
--->  Fetching haddock
--->  Attempting to fetch haddock-2.4.1.tar.gz from http://distfiles.macports.org/haddock
--->  Verifying checksum(s) for haddock
--->  Extracting haddock
--->  Configuring haddock
--->  Building haddock
Error: Target org.macports.build returned: shell command "cd /opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_ports_devel_haddock/work/haddock-2.4.1 && ./Setup build -v" returned error 1
Command output: Building executable: haddock...
Creating dist/build/haddock (and its parents)
Creating dist/build/haddock/haddock-tmp (and its parents)
/opt/local/bin/ghc -o dist/build/haddock/haddock --make -hide-all-packages -no-user-package-conf -i -idist/build/haddock/haddock-tmp -isrc -idist/build/autogen -Idist/build/autogen -Idist/build/haddock/haddock-tmp -optP-include -optPdist/build/autogen/cabal_macros.h -odir dist/build/haddock/haddock-tmp -hidir dist/build/haddock/haddock-tmp -stubdir dist/build/haddock/haddock-tmp -package Cabal-1.6.0.3 -package array-0.2.0.0 -package base-4.1.0.0 -package containers-0.2.0.1 -package directory-1.0.0.3 -package filepath-1.1.0.2 -package ghc-6.10.3 -package ghc-paths-0.1.0.5 -package haskell98-1.0.1.0 -package pretty-1.0.1.0 -O -funbox-strict-fields -O2 -XCPP -XPatternGuards -XDeriveDataTypeable -XScopedTypeVariables -XMagicHash src/Main.hs

src/Main.hs:1:39:
    Warning: -XPatternSignatures is deprecated: use -XScopedTypeVariables or pragma {-# LANGUAGE ScopedTypeVariables#-} instead

src/Haddock/Utils.hs:1:13:
    Warning: -XPatternSignatures is deprecated: use -XScopedTypeVariables or pragma {-# LANGUAGE ScopedTypeVariables#-} instead
[ 1 of 24] Compiling Haddock.Backends.HH ( src/Haddock/Backends/HH.hs, dist/build/haddock/haddock-tmp/Haddock/Backends/HH.o )
[ 2 of 24] Compiling Haddock.Backends.HH2 ( src/Haddock/Backends/HH2.hs, dist/build/haddock/haddock-tmp/Haddock/Backends/HH2.o )
[ 3 of 24] Compiling Haddock.Utils.BlockTable ( src/Haddock/Utils/BlockTable.hs, dist/build/haddock/haddock-tmp/Haddock/Utils/BlockTable.o )
[ 4 of 24] Compiling Haddock.Utils.Html ( src/Haddock/Utils/Html.hs, dist/build/haddock/haddock-tmp/Haddock/Utils/Html.o )
[ 5 of 24] Compiling Paths_haddock    ( dist/build/autogen/Paths_haddock.hs, dist/build/haddock/haddock-tmp/Paths_haddock.o )
[ 6 of 24] Compiling Haddock.Version  ( src/Haddock/Version.hs, dist/build/haddock/haddock-tmp/Haddock/Version.o )
[ 7 of 24] Compiling Haddock.GHC.Utils ( src/Haddock/GHC/Utils.hs, dist/build/haddock/haddock-tmp/Haddock/GHC/Utils.o )
[ 8 of 24] Compiling Haddock.Exception ( src/Haddock/Exception.hs, dist/build/haddock/haddock-tmp/Haddock/Exception.o )
[ 9 of 24] Compiling Haddock.DocName  ( src/Haddock/DocName.hs, dist/build/haddock/haddock-tmp/Haddock/DocName.o )
[10 of 24] Compiling Haddock.Types    ( src/Haddock/Types.hs, dist/build/haddock/haddock-tmp/Haddock/Types.o )
[11 of 24] Compiling Haddock.Utils    ( src/Haddock/Utils.hs, dist/build/haddock/haddock-tmp/Haddock/Utils.o )
[12 of 24] Compiling Haddock.Options  ( src/Haddock/Options.hs, dist/build/haddock/haddock-tmp/Haddock/Options.o )
[13 of 24] Compiling Haddock.GHC.Typecheck ( src/Haddock/GHC/Typecheck.hs, dist/build/haddock/haddock-tmp/Haddock/GHC/Typecheck.o )
[14 of 24] Compiling Haddock.GHC      ( src/Haddock/GHC.hs, dist/build/haddock/haddock-tmp/Haddock/GHC.o )
[15 of 24] Compiling Haddock.Interface.AttachInstances ( src/Haddock/Interface/AttachInstances.hs, dist/build/haddock/haddock-tmp/Haddock/Interface/AttachInstances.o )

src/Haddock/Interface/AttachInstances.hs:94:17:
    Ambiguous occurrence `funTyConName'
    It could refer to either `Haddock.Interface.AttachInstances.funTyConName', defined at src/Haddock/Interface/AttachInstances.hs:108:0
                          or `TypeRep.funTyConName', imported from TypeRep at src/Haddock/Interface/AttachInstances.hs:26:0-13

Error: Status 1 encountered during processing.