[Haskell-cafe] Phantoms

[Malcolm Wallace]

Andrew Coppin <andrewcoppin at btinternet.com> wrote:

> > instnace Show (Foo Int) ...
> > instnace Show (Foo Double) ...
> >   
> 
> ...WHY did I not think of this myself? o_O

Because it is not Haskell'98?  
It requires {-# LANGUAGE OverlappingInstances #-}

Regards,
    Malcolm