{-# LANGUAGE UndecidableInstances #-}

class OldConstraint a => NewtypedConstraint a

instance OldConstraint a => NewtypedConstraint a

perhaps?

Nice thing is you don't even need to do wrapping/unwrapping, like you do with data newtypes.

On Tue, Mar 12, 2013 at 2:18 PM, Roman Cheplyaka <roma@ro-che.info> wrote:

Is there a way to newtype a constraint?

Imagine a type class parameterised over constraints. What do I do if I
want multiple instances for (essentially) the same constraint?

Roman

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