I&#39;m using GHC 7.2.1 and cabal-install 0.8 (Cabal 1.8.0.2), and when<br>&quot;cabal install rsa&quot;<br><br>I got the error<br>$ cabal install rsa<br>Resolving dependencies...<br>Configuring RSA-1.0.6.2...<br>Preprocessing library RSA-1.0.6.2...<br>

Preprocessing executables for RSA-1.0.6.2...<br>Building RSA-1.0.6.2...<br>[1 of 1] Compiling Codec.Crypto.RSA ( Codec/Crypto/RSA.hs, dist/build/Codec/Crypto/RSA.o )<br><br>Codec/Crypto/RSA.hs:580:10:<br>    Duplicate instance declarations:<br>

      instance Random Word8 -- Defined at Codec/Crypto/RSA.hs:580:10-21<br>      instance Random Word8 -- Defined in System.Random<br>cabal: Error: some packages failed to install:<br>RSA-1.0.6.2 failed during the building phase. The exception was:<br>

ExitFailure 1<br><br>Apparently it&#39;s an instance being declared twice.<br>However RSA hackage page states that it compiles under GHC 7.2: <a href="http://hackage.haskell.org/package/RSA">http://hackage.haskell.org/package/RSA</a><br>