[EMAIL PROTECTED] writes:
>
> ghc-4 does not allow what ghc-3.02 did:
>
...
>
> instance Ring a => LeftModule a a where cMul = mul
>
>
> ghc-4 says
> Illegal instance declaration for `LeftModule a a'
> (There must be at least one non-type-variable in the instance head)
>
> If Haskell-2 is going to be this way, then this is somehow against the
> needs of algebra.
>
I think this is a case of options vertigo - try compiling
your source with '-fallow-overlapping-instances
-optC-fallow-undecidable-instances' added to the command line.
--Sigbjorn
