hackage中的软件没有经过彻底测试吗？cabal install xmonad-eval甚至导致以下错误：
$cabal install xmonad-extras
...
[10 of 22] Compiling Hint.Reflection ( src/Hint/Reflection.hs, dist/build/Hint/Reflection.o)
src/Hint/Reflection.hs:75:41:
Couldn't match expected type `[Char]' with actual type `a0 -> String'
Expected type: Id
Actual type: a0 -> String
In the return type of a call of `getUnqualName'
In the first argument of `Class', namely `(getUnqualName c)'
Failed to install hint-0.3.3.5
cabal: Error: some packages failed to install:
hint-0.3.3.5 failed during the building phase. The exception was:
ExitFailure 1
xmonad-extras-0.10.1.2 depends on hint-0.3.3.5 which failed to install.
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