[karmakaze]

I learned the same thing on a project that was using Java 1 non-generics. Not exactly untyped to typed but an analogous experience. Everyone I asked said that it was too big to do. I started anyway by enabling the warnings for nongeneric use. I turned down the reporting limit to 1000 (I think) so as not to be discouraged. After months and months of incremental work alongside my main work, I got under the 1000 warnings. It got a bit trickier after that. In the end, there was exactly 1 bug, where an object.toString was being added to a dropdown box and we'd see it from time to time as Class@hexhash. What I learned then is that it isn't strictly about the bugs, it's the confident way you can navigate the codebase and understand and add in consistent ways. Now I add types to all my Ruby and it's seems normal again.