Duncan Coutts wrote:
On Sun, 2009-02-08 at 07:41 +0000, Dominic Steinitz wrote:
dom@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@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
Duncan, Thanks. I thought it was probably something like that but I thought I had better report it. Dominic.