Old code broken by new Typeable class

[Volker Wysk]

Am Dienstag, 5. August 2014, 12:46:23 schrieb Carter Schonwald:
> i assume 7.6 and 7.8, if we're talking GHC rather than GCC :)
> 
> in 7.8 you can't define userland typeable instances, you need only write
> deriving (Typeable) and you're all set.
> add some CPP to select the instances suitable

So you need to be able to change the definition of the data type, in order to 
add deriving (Typeable). It's not possible to add a Typeable instance 
declaration later.

When you can't change the definition, you're out of luck.

Okay,
V.W.