The only way I can think of doing it would be to instrument all the code, then run the service and subject it to a barrage of automated testing then finally have it produce a report ala coveralls detailing code that hadn’t been executed.
The problem is, even coveralls isn’t great, particularly when macros are being used.
Maybe someone could implement a compiler plugin that could instrument the code in this manner.
In the world of Java such a thing is relativelyly trivial, simply use BCEL (byte code enhancement library) and implement an agent which instruments class files with the extra instructions as they are loaded in.
From what I understand, Erlang doesn’t provide such a facility, at least in a way that doesn’t involve learning how the compiler works.
