[Haskell-cafe] Error when installing RSA (for yesod) with GHC 7.2.1

Yves Parès limestrael at gmail.com
Mon Oct 24 23:13:32 CEST 2011

I'm using GHC 7.2.1 and cabal-install 0.8 (Cabal, and when
"cabal install rsa"

I got the error
$ cabal install rsa
Resolving dependencies...
Configuring RSA-
Preprocessing library RSA-
Preprocessing executables for RSA-
Building RSA-
[1 of 1] Compiling Codec.Crypto.RSA ( Codec/Crypto/RSA.hs,
dist/build/Codec/Crypto/RSA.o )

    Duplicate instance declarations:
      instance Random Word8 -- Defined at Codec/Crypto/RSA.hs:580:10-21
      instance Random Word8 -- Defined in System.Random
cabal: Error: some packages failed to install:
RSA- failed during the building phase. The exception was:
ExitFailure 1

Apparently it's an instance being declared twice.
However RSA hackage page states that it compiles under GHC 7.2:
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