"Show us the code!"(tm)  I mean that in the nicest way possible. But seriously, alternative macro-based code should satisfy the test file for funcpathfile. I think this is impossible. But I don't know the codebase as well as you.

The use case here is prototyping autotrace, which is like strace but for Rust.  This posited --autotrace functionality should allow us to follow exactly all function calls made during a run. This includes calls into trait methods, extensions, and lambdas. This is exactly what funcpathfile!() will provide when injected at the top of all function blocks.  Debug info in Rust is unavailable, and given how this is the common case in other nascent llvm-based languages (D, Julia, Crack-lang, etc) and has been for years and years, I can't expect it to get better quickly. The point of my effort here is to have effective and efficient debugging capabilities, which appear sorely lacking now.

So by all means, I don't care how funcpathfile!() is implemented. But I require its capabilities for visibility into executed code paths.

The current code is deliberately clean not in the sense of Uncle Bob Clean, but cleanly separated and isolated. It can be replace/refactored without effecting any existing functionality.