base-3 vs base-4 (Was: Breakage with 6.10)

[Niklas Broberg]

>  > Btw, I also have problems with the haskell-src-exts that imports
>  > Data.Generics.Instances (to generate Data and Typeable instances).
>  > Where would these have moved to in the new base? And how would I make
>  > the code work with both 6.8.3 and 6.10?
>
> By having it use base-3 rather than 4.

Right, and that's how I quickly fixed it up for now. But this doesn't
sound like a long-term solution to me, I would prefer to use the new
base-4 when possible. The cabal file already includes a conditional
"if flag(splitBase)" to handle really old versions, I guess what I'm
asking for is something similar for this case. Is there a splitSyb
flag or some such?

Though obviously this would only work if the module
Data.Generics.Instances was preserved under that name somewhere else.
If it was renamed or changed (which I suspect), then the hassle of
keeping up to date with older versions will probably be too much, and
I will want to update to the new agenda as soon as 6.10 is released
for real. So what happened to this module? (Is there a migration
quicksheet somewhere?)

Cheers,

/Niklas