Abstractions are the only way to make sense of cryptography. Pretending otherwise leads to cross layer bugs and vulnerabilities. Of course bad abstractions are bad, but that doesn’t mean no abstraction is good.

Feel free to post your challenge snippet.

  pub fn read<P: AsRef<Path>>(path: P) -> io::Result<Vec<u8>> {
    fn inner(path: &Path) -> io::Result<Vec<u8>> {
      let mut file = File::open(path)?;
      let mut bytes = Vec::new();
      file.read_to_end(&mut bytes)?;
      Ok(bytes)
    }
    inner(path.as_ref())
  }

Reference implementations must NOT have abstractions like this. Rust encourages it. Lots of Rust codebase is filled with them. Your feelings for Rust is irrelevant. C is simple and easy to understand, therefore reference implementations must be in C. Period.

...or Common Lisp, or OCaml... why not?!