Hi, I have
dom1@fourier:~/asn1_0> ghc-pkg list --user /home/dom1/.ghc/i386-linux-6.12.1/package.conf.d mtl-1.1.0.2 mtl-2.0.1.0
But I get the following error:
[4 of 6] Compiling LatticeMod ( LatticeMod.hs, interpreted ) [5 of 6] Compiling ConstraintGeneration ( ConstraintGeneration.lhs, interpreted )
ConstraintGeneration.lhs:781:6: Overlapping instances for Monad (Either String) arising from a use of `return' at ConstraintGeneration.lhs:(781,6)-(782,69) Matching instances: instance (Error e) => Monad (Either e) -- Defined in Control.Monad.Trans.Error instance (mtl-1.1.0.2:Control.Monad.Error.Class.Error e) => Monad (Either e) -- Defined in mtl-1.1.0.2:Control.Monad.Error In the expression: return (ExtensibleConstraint (ResStringConstraint v top) (ResStringConstraint top top) b) In the definition of `pvPermittedAlphabetElements': pvPermittedAlphabetElements (S (SV v)) b = return (ExtensibleConstraint (ResStringConstraint v top) (ResStringConstraint top top) b) Failed, modules loaded: ASNTYPE, LatticeMod, Language.ASN1.PER.Integer, Language.ASN1.PER.IntegerAux. If I do
dom1@fourier:~/asn1_0> ghc-pkg hide mtl-2.0.1.0
Then the error goes away. But if I do
ghc-pkg hide mtl-1.1.0.2
Then I still get the error. Is there a wiki page that tells me what to do to upgrade from mtl-1 to mtl-2? Or perhaps someone can tell me what to do? Many thanks, Dominic.