newtype A = A [A] deriving Eq -- context stack overflow

[Wolfgang Thaller]

The following causes a Context reduction stack overflow:

module ContextBug where

newtype A = A [A] deriving (Eq)

test :: A -> A -> Bool
test x y = x == y


Changing from newtype to data helps.

I haven't yet cvs-updated the newest revision to the typechecker, but 
that was just about undecidable instances, I think, so it shouldn't have 
affected this.

Thanks to Kristofer Johannisson <krijo at cs.chalmers.se> for first running 
into this problem.

Cheers,

Wolfgang