[Yhc] coreFunc has extra argument

[Tom Shackell]

Neil Mitchell wrote:
> You don't even need unsafePerformIO! All you need is a proxy a which
> has the right type, this can be done by doing:
> 
> showsType io = showString "(IO " . showsType a . showChar ')'
>      where
>      a = undefined
>      b = asTypeOf (return a) io
> 

That works too, though it still relies on showsType not evaluating it's 
argument - since otherwise it'll eval undefined :S

Tom