[Haskell-cafe] type/class question: toString

Graham Fawcett graham.fawcett at gmail.com
Tue Nov 6 14:02:11 EST 2007

On Nov 6, 2007 12:15 PM, David Benbennick <dbenbenn at gmail.com> wrote:
> In ghc 6.8.1, the error messages are more helpful:
> foo.hs:5:0:
>     Illegal instance declaration for `MyShow String'
>         (All instance types must be of the form (T t1 ... tn)
>          where T is not a synonym.
>          Use -XTypeSynonymInstances if you want to disable this.)
>     In the instance declaration for `MyShow String'

Thanks for the tip. I might give 6.8.1 a try; I still cannot get it to
work in 6.6.1. The problem may exist between the keyboard and the


More information about the Haskell-Cafe mailing list