I want to extract all nightly features used by a crate for some research purposes.
Just to be clear, "nightly features" means codes like
#![feature(...)]", but not crate provided optional features.
I tried using regex, and it works, but not accurate enough. cfg defined features may not be detected:
#![cfg_attr(target_os = "macos", feature(...))].
So I turn to rustc compiler, I wish to modify some source code and print out what features crate uses. Now I'm still trying to find out how rustc deals with nightly features.
I hope someone can give me some tips and help about the process of rustc dealing with nightly features. I'm almost lost in codes.
I have post this question on stack overflow: rust - How to extract nightly features used in a crate? - Stack Overflow, just wish I can get some ideas here, too.