I had defined a data type similar to the following:

data Record = Record { name :: String, age :: Int }

Later, I realized I needed it be an ADT defined like:
data Record a = Record { name :: String, age :: Int, resource :: a }

The change turned out to be fairly well contained and probably only took me a half hour to propagate up. However, I see the potential for this to be a bigger job. Are there any editors that automate that kind of refactoring?

-Ryan