<a href="http://darcs.haskell.org/packages/cgi-undecidable/">http://darcs.haskell.org/packages/cgi-undecidable/</a><br><br>There only 3 or 4 lines of source code, but it can't be installed.<br><br>The ghc version is 6.6
.<br><br>Undecidable.hs:23:0:<br> Duplicate instance declarations:<br> instance [overlap ok] (MonadTrans t, MonadCGI m, Monad (t m)) =><br> MonadCGI (t m)<br> -- Defined at Undecidable.hs
:23:0<br> instance [overlap ok] (MonadTrans t, MonadCGI m, Monad (t m)) =><br> MonadCGI (t m)<br> -- Defined in Network.CGI.Monad<br><br>