我尝试通过运行以下命令安装haddock cabal安装haddock,但我遇到以下问题.

leonzo@lion:~/opt$cabal install haddock

Resolving dependencies...

Configuring haddock-2.11.0...

Building haddock-2.11.0...

Preprocessing library haddock-2.11.0...

unused terminals: 1

[ 1 of 31] Compiling Haddock.Backends.HaddockDB ( src/Haddock/Backends/HaddockDB.hs, dist/build/Haddock/Backends/HaddockDB.o )

[ 2 of 31] Compiling Haddock.Backends.Xhtml.Types ( src/Haddock/Backends/Xhtml/Types.hs, dist/build/Haddock/Backends/Xhtml/Types.o )

[ 3 of 31] Compiling Haddock.Convert ( src/Haddock/Convert.hs, dist/build/Haddock/Convert.o )

[ 4 of 31] Compiling Paths_haddock ( dist/build/autogen/Paths_haddock.hs, dist/build/Paths_haddock.o )

[ 5 of 31] Compiling Haddock.GhcUtils ( src/Haddock/GhcUtils.hs, dist/build/Haddock/GhcUtils.o )

[ 6 of 31] Compiling Haddock.Version ( src/Haddock/Version.hs, dist/build/Haddock/Version.o )

[ 7 of 31] Compiling Haddock.Lex ( dist/build/Haddock/Lex.hs, dist/build/Haddock/Lex.o )

[ 8 of 31] Compiling Haddock.Types ( src/Haddock/Types.hs, dist/build/Haddock/Types.o )

[ 9 of 31] Compiling Haddock.Utils ( src/Haddock/Utils.hs, dist/build/Haddock/Utils.o )

[10 of 31] Compiling Haddock.Options ( src/Haddock/Options.hs, dist/build/Haddock/Options.o )

[11 of 31] Compiling Haddock.Backends.Xhtml.Themes ( src/Haddock/Backends/Xhtml/Themes.hs, dist/build/Haddock/Backends/Xhtml/Themes.o )

讯享网

[12 of 31] Compiling Haddock.Backends.Xhtml.Utils ( src/Haddock/Backends/Xhtml/Utils.hs, dist/build/Haddock/Backends/Xhtml/Utils.o )

[13 of 31] Compiling Haddock.Backends.LaTeX ( src/Haddock/Backends/LaTeX.hs, dist/build/Haddock/Backends/LaTeX.o )

[14 of 31] Compiling Haddock.Backends.Hoogle ( src/Haddock/Backends/Hoogle.hs, dist/build/Haddock/Backends/Hoogle.o )

[15 of 31] Compiling Haddock.Interface.AttachInstances ( src/Haddock/Interface/AttachInstances.hs, dist/build/Haddock/Interface/AttachInstances.o )

[16 of 31] Compiling Haddock.Interface.Rename ( src/Haddock/Interface/Rename.hs, dist/build/Haddock/Interface/Rename.o )

[17 of 31] Compiling Haddock.Doc ( src/Haddock/Doc.hs, dist/build/Haddock/Doc.o )

[18 of 31] Compiling Haddock.Parse ( dist/build/Haddock/Parse.hs, dist/build/Haddock/Parse.o )

[19 of 31] Compiling Haddock.Interface.ParseModuleHeader ( src/Haddock/Interface/ParseModuleHeader.hs, dist/build/Haddock/Interface/ParseModuleHeader.o )

[20 of 31] Compiling Haddock.Interface.LexParseRn ( src/Haddock/Interface/LexParseRn.hs, dist/build/Haddock/Interface/LexParseRn.o )

src/Haddock/Interface/LexParseRn.hs:67:52:

Not in scope: type constructor or class `SafeHaskellMode'

cabal: Error: some packages failed to install:

haddock-2.11.0 failed during the building phase. The exception was:

ExitFailure 1

leonzo@lion:~/opt$

有没有人知道如何处理这个烂摊子？

编辑

我的ghc版本是7.4.1