[Haskell-cafe] Problem on overlapping instances

[Steffen Schuldenzucker]

Am 05.01.2011 09:24, schrieb Magicloud Magiclouds:
> Hi,
>    I am using Data.Binary which defined "instance Binary a =>  Binary
> [a]". Now I need to define "instance Binary [String]" to make
> something special for string list.
>    How to make it work? I looked into the chapter of
> overlappinginstances, nothing works.

Just a guess: Have you enabled TypeSynonymInstances? (As String is a 
type synonym, at least this extension would be required)
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