Djinn Doesn't Build

[Duncan Coutts]

On Sun, 2009-02-08 at 07:41 +0000, Dominic Steinitz wrote:
> > dom at linux-6ofq:~/djinn-2009.2.1> runghc Setup.lhs build
> > Preprocessing executables for djinn-2009.2.1...
> > Building djinn-2009.2.1...
> > [1 of 7] Compiling REPL             ( src/REPL.hs, dist/build/djinn/djinn-tmp/REPL.o )
> > 
> > src/REPL.hs:18:17:
> >     Ambiguous type variable `e' in the constraint:
> >       `Control.Exception.Exception e'
> >         arising from a use of `Control.Exception.catch'
> >                      at src/REPL.hs:(18,17)-(33,12)
> >     Probable fix: add a type signature that fixes these type variable(s)
> 
> > dom at linux-6ofq:~/djinn-2009.2.1> ghc --version
> > The Glorious Glasgow Haskell Compilation System, version 6.10.1

Build it against base-3 then it works. This is what cabal-install does.

$ cabal install djinn

This applies to a load of packages written before base-4 came out (which
changed the exceptions api). Many such packages did not list
build-depends: base <4 in their .cabal files. There is what's basically
a compatibility hack in cabal-install to make this continue to work for
old packages.

Duncan