[nhc-users] Re: No default for MutualRecursion.PP

[Christian Maeder]

Sorry, that I came up again with such an old bug (a pity it isn't fixed yet)

http://www.cs.york.ac.uk/fp/nhc98/nhc-users-archive/0107.html

Christian

I wrote:

> No default for  MutualRecursion.PP at 23:1-24:18.(174,[(148,187)])
> No default for  MutualRecursion.PP at 19:1-20:18.(183,[(148,186)])
> 
> -- --------------------------------------------------------------------
> 
> module MutualRecursion where
> 
> data A a = A a | BasA (B a)
> 
> data B a = B a | AasB (A a)
> 
> class PP a where
>     pp :: a -> String
> 
> instance PP a => PP (A a) where
>     pp (A a) = pp a
>     pp (BasA b) = pp b
> 
> instance PP a => PP (B a) where
>     pp (B a) = pp a
>     pp (AasB b) = pp b
> 
> fA :: PP a => A a -> String
> fA (A a) = pp a
> fA (BasA b) = fB b
> 
> fB :: PP a => B a -> String
> fB (B b) = pp b
> fB (AasB a) = fA a
>