It's a small tool that lets you automatically generate graphviz/dot code that visualize the relations between data types, types and type classes.
This sounds very familiar to my SourceGraph package that's already on Hackage...
I hope that some friendly competition can spur both of us to deliver even better tooling :)
You, however, also add the type signatures to your graph; I have the sneaking suspicion that this could get too noisy if you also try to visualise functions in a large module.
Visualizing every aspect is probably never a good idea. At the moment I'm sketching on alternative visualizations where only relations between modules show up or where the data constructors for data types aren't visualized. On a related note: has anyone yet tried to visualize the flow of the IO monad in an application? -- Oscar