Working with OO code featuring interfaces and inheritance, finding where the actual code you're executing can be tricky. Are there any interfaces that are optimized for that kind of search?
The IDEs that I'm familiar with (IntelliJ, Eclipse) give some useful features (you can view type hierarchies, see where a method is called, see if a method is overridden in the current project, etc), but I can imagine other things they don't do.
One in particular that I've thought about is reifying the process of navigating code, so I could see that I've navigated from X to the interface it called, and from there to a class implementing the interface, and so on…
Another idea might be integrating static analysis, so that you could see a method might only be called by types X,Y,Z.