Have you ever seen a Regex::new(..).unwrap() fail? It sounds like maybe not. It also sounds like you haven't seen an 'unwrap()' fail either.

> Without it, you just know that some regex somewhere is invalid.

That's bologna. As I discuss in the blog post, 'unwrap()' tells you the line number at which it panicked. There's even an example showing exactly this. There's even another example showing what happens when you call 'Regex::new(..).unwrap()' and it fails[1]:

    fn main() {
        regex::Regex::new(r"foo\p{glyph}bar").unwrap();
    }

And running it:

    $ cargo run
        Finished dev [unoptimized + debuginfo] target(s) in 0.00s
         Running `target/debug/rust-panic`
    thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: Syntax(
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    regex parse error:
        foo\p{glyph}bar
           ^^^^^^^^^
    error: Unicode property not found
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    )', main.rs:4:36
    note: run with `RUST_BACKTRACE=1` environment variable to display a backtrac

So you get the line number (as is standard with any 'unwrap()') and you get the actual error message from the regex. No need to even enable the backtrace. You just don't need 'expect()' here.

[1]: https://blog.burntsushi.net/unwrap/#why-not-use-expect-inste...