This conversation is super frustrating. This is occurring in the context of compilation speed. So if you're measuring compilation speed by LoC (which is itself just a heuristic), then you should, at minimum, count as many lines of code that are actually being compiled. That's what `cargo vendor` does: it fetches the source code of all dependencies that are needed to build the project.

You are losing sight of the forest through the trees here. This isn't an abstract argument about what is or isn't part of a program. This is a concrete measurement heuristic that has precisely defined inputs.